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Working With Wallet Smart Contracts

👋 Introduction

Learning how wallets and transactions work on TON before beginning smart contracts development is essential. This knowledge will help developers understand the interaction between wallets, transactions, and smart contracts to implement specific development tasks.

In this section we’ll learn to create operations without using pre-configured functions to understand development workflows. All references necessary for the analysis of this tutorial are located in the references chapter.

💡 Prerequisites

This tutorial requires basic knowledge of Javascript, Typescript, and Golang. It is also necessary to hold at least 3 TON (which can be stored in an exchange account, a non-custodial wallet, or by using the telegram bot wallet). It is necessary to have a basic understanding of cell, addresses in TON, blockchain of blockchains to understand this tutorial.

MAINNET DEVELOPMENT IS ESSENTIAL

Working with the TON Testnet often leads to deployment errors, difficulty tracking transactions, and unstable network functionality. Therefore, it could be beneficial to complete most development on the TON Mainnet to potentially avoid these issues, which might be necessary to reduce the number of transactions and thereby possibly minimize fees.

Source Code

All code examples used in this tutorial can be found in the following GitHub repository.

✍️ What You Need To Get Started

  • Ensure NodeJS is installed.
  • Specific Ton libraries are required and include: @ton/ton 13.5.1+, @ton/core 0.49.2+ and @ton/crypto 3.2.0+.

OPTIONAL: If you prefer to use GO instead JS, it is necessary to install the tonutils-go library and the GoLand IDE to conduct development on TON. This library will be used in this tutorial for the GO version.

npm i --save @ton/ton @ton/core @ton/crypto

⚙ Set Your Environment

In order to create a TypeScript project its necessary to conduct the following steps in order:

  1. Create an empty folder (which we’ll name WalletsTutorial).
  2. Open the project folder using the CLI.
  3. Use the followings commands to set up your project:
npm init -y
npm install typescript @types/node ts-node nodemon --save-dev
npx tsc --init --rootDir src --outDir build \ --esModuleInterop --target es2020 --resolveJsonModule --lib es6 \ --module commonjs --allowJs true --noImplicitAny false --allowSyntheticDefaultImports true --strict false
info

To help us carry out the next process a ts-node is used to execute TypeScript code directly without precompiling. nodemon is used to restart the node application automatically when file changes in the directory are detected.

  1. Next, remove these lines from tsconfig.json:
  "files": [
"\\",
"\\"
]
  1. Then, create a nodemon.json config in your project root with the following content:
{
"watch": ["src"],
"ext": ".ts,.js",
"ignore": [],
"exec": "npx ts-node ./src/index.ts"
}
  1. Add this script to package.json instead of "test", which is added when the project is created:
"start:dev": "npx nodemon"
  1. Create src folder in the project root and index.ts file in this folder.
  2. Next, the following code should be added:
async function main() {
console.log("Hello, TON!");
}

main().finally(() => console.log("Exiting..."));
  1. Run the code using terminal:
npm run start:dev
  1. Finally, the console output will appear.

Blueprint

The TON Community created an excellent tool for automating all development processes (deployment, contract writing, testing) called Blueprint. However, we will not be needing such a powerful tool, so it is suggested that the instructions above are followed.

OPTIONAL: When using Golang, follow these instructions::

  1. Install the GoLand IDE.
  2. Create a project folder and go.mod file using the following content (the version of Go may need to be changed to conduct this process if the current version being used it outdated):
module main

go 1.20
  1. Type the following command into the terminal:
go get github.com/xssnick/tonutils-go
  1. Create the main.go file in the root of your project with following content:
package main

import (
"log"
)

func main() {
log.Println("Hello, TON!")
}
  1. Change the name of the module in the go.mod to main.
  2. Run the code above until the output in the terminal is displayed.
info

It is also possible to use another IDE since GoLand isn’t free, but it is preferred.

IMPORTANT

All coding components should be added to the main function that was created in the ⚙ Set Your Environment section.

Additionally, only the imports required for a specific code section will be specified in each new section and new imports will need to be added and combined with old ones.

🚀 Let's Get Started!

In this tutorial we’ll learn which wallets (version’s 3 and 4) are most often used on TON Blockchain and get acquainted with how their smart contracts work. This will allow developers to better understand the different transaction types on the TON platform to make it simpler to create transactions, send them to the blockchain, deploy wallets, and eventually, be able to work with high-load wallets.

Our main task is to build transactions using various objects and functions for @ton/ton, @ton/core, @ton/crypto (ExternalMessage, InternalMessage, Signing etc.) to understand what transactions look like on a bigger scale. To carry out this process we'll make use of two main wallet versions (v3 and v4) because of the fact that exchanges, non-custodial wallets, and most users only used these specific versions.

note

There may be occasions in this tutorial when there is no explanation for particular details. In these cases, more details will be provided in later stages of this tutorial.

IMPORTANT: Throughout this tutorial wallet v3 code is used to better understand the wallet development process. It should be noted that version v3 has two sub-versions: r1 and r2. Currently, only the second version is being used, this means that when we refer to v3 in this document it means v3r2.

💎 TON Blockchain Wallets

All wallets that operate and run on TON Blockchain are actually smart contracts, in the same way, everything operating on TON is a smart contract. Like most blockchains, it is possible to deploy smart contracts on the network and customize them for different uses. Thanks to this feature, full wallet customization is possible. On TON wallet smart contracts help the platform communicate with other smart contract types. However, it is important to consider how wallet communication takes place.

Wallet Communication

Generally, there are two transaction types on TON Blockchain: internal and external. External transactions allow for the ability to send messages to the blockchain from the outside world, thus allowing for the communication with smart contracts that accept such transactions. The function responsible for carrying out this process is as follows:

() recv_external(slice in_msg) impure {
;; some code
}

Before we dive into more details concerning wallets, let’s look at how wallets accept external transactions. On TON, all wallets hold the owner’s public key, seqno, and subwallet_id. When receiving an external transaction, the wallet uses the get_data() method to retrieve data from the storage portion of the wallet. It then conducts several verification procedures and decides whether to accept the transaction or not. This process is conducted as follows:

() recv_external(slice in_msg) impure {
var signature = in_msg~load_bits(512); ;; get signature from the message body
var cs = in_msg;
var (subwallet_id, valid_until, msg_seqno) = (cs~load_uint(32), cs~load_uint(32), cs~load_uint(32)); ;; get rest values from the message body
throw_if(35, valid_until <= now()); ;; check the relevance of the transaction
var ds = get_data().begin_parse(); ;; get data from storage and convert it into a slice to be able to read values
var (stored_seqno, stored_subwallet, public_key) = (ds~load_uint(32), ds~load_uint(32), ds~load_uint(256)); ;; read values from storage
ds.end_parse(); ;; make sure we do not have anything in ds variable
throw_unless(33, msg_seqno == stored_seqno);
throw_unless(34, subwallet_id == stored_subwallet);
throw_unless(35, check_signature(slice_hash(in_msg), signature, public_key));
accept_message();

💡 Useful links:

"load_bits()" in docs

"get_data()" in docs

"begin_parse()" in docs

"end_parse()" in docs

"load_int()" in docs

"load_uint()" in docs

"check_signature()" in docs

"slice_hash()" in docs

"accept_message()" in docs

Now let’s take a closer look.

Replay Protection - Seqno

Transaction replay protection in the wallet smart contract is directly related to the transaction seqno (Sequence Number) which keeps track of which transactions are sent in which order. It is very important that a single transaction is not repeated from a wallet because it throws off the integrity of the system entirely. If we further examine smart contract code within a wallet, the seqno is typically handled as follows:

throw_unless(33, msg_seqno == stored_seqno);

This line of code above checks the seqno, which comes in the transaction and checks it with seqno, which is stored in a smart contract. The contract returns an error with 33 exit code if they do not match. So if the sender passed invalid seqno, it means that he made some mistake in the transaction sequence, and the contract protects against such cases.

note

It's also essential to consider that external messages can be sent by anyone. This means that if you send 1 TON to someone, someone else can repeat this message. However, when the seqno increases, the previous external message becomes invalid, and no one will be able to repeat it, thus preventing the possibility of stealing your funds.

Signature

As mentioned earlier, wallet smart contracts accept external transactions. However, these transactions come from the outside world and that data cannot be 100% trusted. Therefore, each wallet stores the owner's public key. The smart contract uses a public key to verify the legitimacy of the transaction signature when receiving an external transaction that the owner signed with the private key. This verifies that the transaction is actually from the contract owner.

To carry out this process, the wallet must first obtain the signature from the incoming message which loads the public key from storage and validates the signature using the following process:

var signature = in_msg~load_bits(512);
var ds = get_data().begin_parse();
var (stored_seqno, stored_subwallet, public_key) = (ds~load_uint(32), ds~load_uint(32), ds~load_uint(256));
throw_unless(35, check_signature(slice_hash(in_msg), signature, public_key));

And if all verification processes are completed correctly, the smart contract accepts the message and processes it:

accept_message();
accept_message()

Because the transaction comes from the outside world, it does not contain the Toncoin required to pay the transaction fee. When sending TON using the accept_message() function, a gas_credit (at the time of writing its value is 10,000 gas units) is applied which allows the necessary calculations to be carried out for free if the gas does not exceed the gas_credit value. After the accept_message() function is used, all the gas spent (in TON) is taken from the balance of the smart contract. More can be read about this process here.

Transaction Expiration

Another step used to check the validity of external transactions is the valid_until field. As you can see from the variable name, this is the time in UNIX before the transaction is valid. If this verification process fails, the contract completes the processing of the transaction and returns the 32 exit code follows:

var (subwallet_id, valid_until, msg_seqno) = (cs~load_uint(32), cs~load_uint(32), cs~load_uint(32));
throw_if(35, valid_until <= now());

This algorithm works to protect against the susceptibility of various errors when the transaction is no longer valid but was still sent to the blockchain for an unknown reason.

Wallet v3 and Wallet v4 Differences

The only difference between Wallet v3 and Wallet v4 is that Wallet v4 makes use of plugins that can be installed and deleted. These plugins are special smart contracts which are able to request a specific number of TON at a specific time from a wallet smart contract.

Wallet smart contracts, in turn, will send the required amount of TON in response without the need for the owner to participate. This is similar to the subscription model for which plugins are created. We will not learn these details, because this is out of the scope of this tutorial.

How Wallets facilitate communication with Smart Contracts

As we discussed earlier, a wallet smart contract accepts external transactions, validates them and accepts them if all checks are passed. The contract then starts the loop of retrieving messages from the body of external messages then creates internal messages and sends them to the blockchain as follows:

cs~touch();
while (cs.slice_refs()) {
var mode = cs~load_uint(8); ;; load transaction mode
send_raw_message(cs~load_ref(), mode); ;; get each new internal message as a cell with the help of load_ref() and send it
}
touch()

On TON, all smart contracts run on the stack-based TON Virtual Machine (TVM). ~ touch() places the variable cs on top of the stack to optimize the running of code for less gas.

Since a maximum of 4 references can be stored in one cell, we can send a maximum of 4 internal messages per external message.

💡 Useful links:

"slice_refs()" in docs

"send_raw_message() and transaction modes" in docs

"load_ref()" in docs

📬 External and Internal Transactions

In this section, we’ll learn more about internal and external transactions and we’ll create transactions and send them to the network to minimize the use of pre-cooked functions.

To carry out this process it is necessary to make use of a ready-made wallet to make the task easier. To accomplish this:

  1. Install the wallet app (e.g., Tonkeeper is used by the author)
  2. Switch wallet app to v3r2 address version
  3. Deposit 1 TON into the wallet
  4. Send the transaction to another address (you can send to yourself, to the same wallet).

This way, the Tonkeeper wallet app will deploy the wallet contract and we can use it for the following steps.

note

At the time of writing, most wallet apps on TON by default use the wallet v4 version. Plugins are not required in this tutorial and we’ll make use of the functionality provided by wallet v3. During use, Tonkeeper allows the user to choose the version of the wallet they want. Therefore, it is recommended to deploy wallet version 3 (wallet v3).

TL-B

As noted, everything in TON Blockchain is a smart contract consisting of cells. To properly serialize and deserialize the data we need standards. To accomplish the serialization and deserialization process, TL-B was created as a universal tool to describe different data types in different ways with different sequences inside cells.

In this section, we’ll examine block.tlb. This file will be very useful during future development, as it describes how different cells should be assembled. In our case specifically, it details the intricacies of internal and external transactions.

info

Basic information will be provided within this guide. For further details, please refer to our TL-B documentation to learn more about TL-B.

CommonMsgInfo

Initially, each message must first store CommonMsgInfo (TL-B) or CommonMsgInfoRelaxed (TL-B). This allows us to define technical details that relate to the transaction type, transaction time, recipient address, technical flags, and fees.

By reading block.tlb file, we can notice three types of CommonMsgInfo: int_msg_info$0, ext_in_msg_info$10, ext_out_msg_info$11. We will not go into specific details detailing the specificities of the ext_out_msg_info TL-B structure. That said, it is an external transaction type that a smart contract can send for using as external logs. For examples of this format, consider having a closer look at the Elector contract.

Looking at TL-B, you’ll notice that only the CommonMsgInfo is available when used with the ext_in_msg_info type. This is because transaction type fields such as src, created_lt, created_at, and others are rewritten by validators during transaction handling. In this case, the src transaction type is most important because when transactions are sent, the sender is unknown, and is written by validators during verification. This ensures that the address in the src field is correct and cannot be manipulated.

However, the CommonMsgInfo structure only supports the MsgAddress specification, but the sender’s address is typically unknown and it is required to write the addr_none (two zero bits 00). In this case, the CommonMsgInfoRelaxed structure is used, which supports the addr_none address. For the ext_in_msg_info (used for incoming external messages), the CommonMsgInfo structure is used because these message types don’t make use of a sender and always use the MsgAddressExt structure (the addr_none$00 meaning two zero bits), which means there is no need to overwrite the data.

note

The numbers after $ symbol are the bits that are required to store at the beginning of a certain structure, for further identification of these structures during reading (deserialization).

Internal Transaction Creation

Internal transactions are used to send messages between contracts. When analyzing various contract types (such as NFTs and Jetons) that send messages where the writing of contracts is considered, the following lines of code are often used:

var msg = begin_cell()
.store_uint(0x18, 6) ;; or 0x10 for non-bounce
.store_slice(to_address)
.store_coins(amount)
.store_uint(0, 1 + 4 + 4 + 64 + 32 + 1 + 1) ;; default message headers (see sending messages page)
;; store something as a body

Let’s first consider 0x18 and 0x10 (x - hexadecimal), which are hexadecimal numbers laid out in the following manner (given that we allocate 6 bits): 011000 and 010000. This means that the code above can be overwritten as follows:

var msg = begin_cell()
.store_uint(0, 1) ;; this bit indicates that we send an internal message according to int_msg_info$0
.store_uint(1, 1) ;; IHR Disabled
.store_uint(1, 1) ;; or .store_uint(0, 1) for 0x10 | bounce
.store_uint(0, 1) ;; bounced
.store_uint(0, 2) ;; src -> two zero bits for addr_none
.store_slice(to_address)
.store_coins(amount)
.store_uint(0, 1 + 4 + 4 + 64 + 32 + 1 + 1) ;; default message headers (see sending messages page)
;; store something as a body

Now let’s go through each option in detail:

OptionExplanation
IHR DisabledCurrently, this option is disabled (which means we store 1) because Instant Hypercube Routing is not fully implemented. In addition, this will be needed when a large number of Shardchains are live on the network. More can be read about the IHR Disabled option in the tblkch.pdf (chapter 2).
BounceWhile sending transactions, a variety of errors can occur during smart contract processing. To avoid losing TON, it is necessary to set the Bounce option to 1 (true). In this case, if any contract errors occur during transaction processing, the transaction will be returned to the sender, and the same amount of TON will be received minus fees. More can be read about non-bounceable messages here.
BouncedBounced transactions are transactions that are returned to the sender because an error occurred while processing the transaction with a smart contract. This option tells you whether the transaction received is bounced or not.
SrcThe Src is the sender address. In this case, two zero bits are written to indicate the addr_none address.

The next two lines of code:

...
.store_slice(to_address)
.store_coins(amount)
...
  • we specify the recipient and the number of TON to be sent.

Finally, let’s look at the remaining lines of code:

...
.store_uint(0, 1) ;; Extra currency
.store_uint(0, 4) ;; IHR fee
.store_uint(0, 4) ;; Forwarding fee
.store_uint(0, 64) ;; Logical time of creation
.store_uint(0, 32) ;; UNIX time of creation
.store_uint(0, 1) ;; State Init
.store_uint(0, 1) ;; Message body
;; store something as a body
OptionExplanation
Extra currencyThis is a native implementation of existing jettons and is not currently in use.
IHR feeAs mentioned, the IHR is not currently in use, so this fee is always zero. More can be read about this in the tblkch.pdf (3.1.8).
Forwarding feeA forwarding message fee. More can be read about this in the fees documentation.
Logical time of creationThe time used to create the correct transaction queue.
UNIX tome of creationThe time the transaction was created in UNIX.
State InitCode and source data for deploying a smart contract. If the bit is set to 0, it means that we do not have a State Init. But if it is set to 1, then another bit needs to be written which indicates whether the State Init is stored in the same cell (0) or written as a reference (1).
Message bodyThis part defines how the message body is stored. At times the message body is too large to fit into the message itself. In this case, it should be stored as a reference whereby the bit is set to 1 to show that the body is used as a reference. If the bit is 0, the body is in the same cell as the message.

The values outlined above (including src) excluding the State Init and the Message Body bits, are rewritten by validators.

note

If the number value fits within fewer bits than is specified, then the missing zeros are added to the left side of the value. For example, 0x18 fits within 5 bits -> 11000. However, since 6 bits were specified, the end result becomes 011000.

Next, we’ll begin preparing a transaction, which will be sent Toncoins to another wallet v3. First, let’s say a user wants to send 0.5 TON to themselves with the text "Hello, TON!", refer to this section of our documentation to learn (How to send message with a comment).

import { beginCell } from '@ton/core';

let internalMessageBody = beginCell().
storeUint(0, 32). // write 32 zero bits to indicate that a text comment will follow
storeStringTail("Hello, TON!"). // write our text comment
endCell();

Above we created an InternalMessageBody in which the body of our message is stored. Note that when storing text that does not fit into a single Cell (1023 bits), it is necessary to split the data into several cells according to the following documentation. However, in this case the high-level libraries creates cells according to requirements, so at this stage there is no need to worry about it.

Next, the InternalMessage is created according to the information we have studied earlier as follows:

import { toNano, Address } from '@ton/ton';

const walletAddress = Address.parse('put your wallet address');

let internalMessage = beginCell().
storeUint(0, 1). // indicate that it is an internal message -> int_msg_info$0
storeBit(1). // IHR Disabled
storeBit(1). // bounce
storeBit(0). // bounced
storeUint(0, 2). // src -> addr_none
storeAddress(walletAddress).
storeCoins(toNano("0.2")). // amount
storeBit(0). // Extra currency
storeCoins(0). // IHR Fee
storeCoins(0). // Forwarding Fee
storeUint(0, 64). // Logical time of creation
storeUint(0, 32). // UNIX time of creation
storeBit(0). // No State Init
storeBit(1). // We store Message Body as a reference
storeRef(internalMessageBody). // Store Message Body as a reference
endCell();

Creating a Message

It is necessary to retrieve the seqno (sequence number) of our wallet smart contract. To accomplish this, a Client is created which will be used to send a request to run the Get method "seqno" of our wallet. It is also necessary to add a seed phrase (which you saved during creating a wallet here) to sign our transaction via the following steps:

import { TonClient } from '@ton/ton';
import { mnemonicToWalletKey } from '@ton/crypto';

const client = new TonClient({
endpoint: "https://toncenter.com/api/v2/jsonRPC",
apiKey: "put your api key" // you can get an api key from @tonapibot bot in Telegram
});

const mnemonic = 'put your mnemonic'; // word1 word2 word3
let getMethodResult = await client.runMethod(walletAddress, "seqno"); // run "seqno" GET method from your wallet contract
let seqno = getMethodResult.stack.readNumber(); // get seqno from response

const mnemonicArray = mnemonic.split(' '); // get array from string
const keyPair = await mnemonicToWalletKey(mnemonicArray); // get Secret and Public keys from mnemonic

Therefore, the seqno, keys, and internal message need to be sent. Now we need to create a message for our wallet and store the data in this message in the sequence used at the beginning of the tutorial. This is accomplished as follows:

import { sign } from '@ton/crypto';

let toSign = beginCell().
storeUint(698983191, 32). // subwallet_id | We consider this further
storeUint(Math.floor(Date.now() / 1e3) + 60, 32). // Transaction expiration time, +60 = 1 minute
storeUint(seqno, 32). // store seqno
storeUint(3, 8). // store mode of our internal transaction
storeRef(internalMessage); // store our internalMessage as a reference

let signature = sign(toSign.endCell().hash(), keyPair.secretKey); // get the hash of our message to wallet smart contract and sign it to get signature

let body = beginCell().
storeBuffer(signature). // store signature
storeBuilder(toSign). // store our message
endCell();

Note that here no .endCell() was used in the definition of the toSign. The fact is that in this case it is necessary to transfer toSign content directly to the message body. If writing a cell was required, it would have to be stored as a reference.

Wallet V4

In addition to basic verification process we learned bellow for the Wallet V3, Wallet V4 smart contracts extracts the opcode to determine whether a simple translation or a transaction associated with the plugin is required. To match this version, it is necessary to add the storeUint(0, 8). (JS/TS), MustStoreUInt(0, 8). (Golang) functions after writing the seqno (sequence number) and before specifying the transaction mode.

External Transaction Creation

To deliver any internal message to a blockchain from the outside world, it is necessary to send it within an external transaction. As we have previously considered, it is necessary to only make use of the ext_in_msg_info$10 structure, as the goal is to send an external message to our contract. Now, let's create an external message that will be sent to our wallet:

let externalMessage = beginCell().
storeUint(0b10, 2). // 0b10 -> 10 in binary
storeUint(0, 2). // src -> addr_none
storeAddress(walletAddress). // Destination address
storeCoins(0). // Import Fee
storeBit(0). // No State Init
storeBit(1). // We store Message Body as a reference
storeRef(body). // Store Message Body as a reference
endCell();
OptionExplanation
SrcThe sender address. Since an incoming external message cannot have a sender, there will always be 2 zero bits (an addr_none TL-B).
Import FeeThe fee used to pay for importing incoming external messages.
State InitUnlike the Internal Message, the State Init within the external message is needed to deploy a contract from the outside world. The State Init used in conjunction with the Internal Message allows one contract to deploy another.
Message BodyThe message that must be sent to the contract for processing.
0b10

0b10 (b - binary) denotes a binary record. In this process, two bits are stored: 1 and 0. Thus we specify that it's ext_in_msg_info$10.

Now we have a completed message that is ready to be sent to our contract. To accomplish this, it should first be serialized to a BOC (Bag of Cells), then be sent using the following code:

console.log(externalMessage.toBoc().toString("base64"))

client.sendFile(externalMessage.toBoc());

💡 Useful link:

More about Bag of Cells

As a result, we got the output of our BOC in the console and the transaction sent to our wallet. By copying the base64 encoded string, it is possible to manually send our transaction and retrieve the hash using toncenter.

👛 Deploying a Wallet

We have learned the basics of creating messages, which will now be helpful for deploying the wallet. In the past, we have deployed wallet via wallet app, but in this case we’ll need to deploy our wallet manually.

In this section we’ll go over how to create a wallet (wallet v3) from scratch. You’ll learn how to compile the code for a wallet smart contract, generate a mnemonic phrase, receive a wallet address, and deploy a wallet using external transactions and State Init (state initialization).

Generating a Mnemonic

The first thing needed to correctly create a wallet is to retrieve a private and public key. To accomplish this task it is necessary to generate a mnemonic seed phrase and then extract private and public keys using cryptographic libraries.

This is accomplished as follows:

import { mnemonicToWalletKey, mnemonicNew } from '@ton/crypto';

// const mnemonicArray = 'put your mnemonic'.split(' ') // get our mnemonic as array
const mnemonicArray = await mnemonicNew(24); // 24 is the number of words in a seed phrase
const keyPair = await mnemonicToWalletKey(mnemonicArray); // extract private and public keys from mnemonic
console.log(mnemonicArray) // if we want, we can print our mnemonic

The private key is needed to sign transactions and the public key is stored in the wallet’s smart contract.

IMPORTANT

It is necessary to output the generated mnemonic seed phrase to the console then save and use it (as detailed in the previous section) in order to use the same key pair each time the wallet’s code is run.

Subwallet IDs

One of the most notable benefits of wallets being smart contracts is the ability to create a vast number of wallets using just one private key. This is because the addresses of smart contracts on TON Blockchain are computed using several factors including the stateInit. The stateInit contains the code and initial data, which is stored in the blockchain’s smart contract storage.

By changing just one bit within the stateInit, a different address can be generated. That is why the subwallet_id was initially created. The subwallet_id is stored in the contract storage and it can be used to create many different wallets (with different subwallet IDs) with one private key. This functionality can be very useful when integrating various wallet types with centralized service such as exchanges.

The default subwallet_id value is 698983191 according to the line of code below taken from the TON Blockchain’s source code:

res.wallet_id = td::as<td::uint32>(res.config.zero_state_id.root_hash.as_slice().data());

It is possible to retrieve genesis block information (zero_state) from the configuration file. Understanding the complexities and details of this is not necessary but it's important to remember that the default value of the subwallet_id is 698983191.

Each wallet contract checks the subwallet_id field for external transactions to avoid instances when requests were sent to wallet with another ID:

var (subwallet_id, valid_until, msg_seqno) = (cs~load_uint(32), cs~load_uint(32), cs~load_uint(32));
var (stored_seqno, stored_subwallet, public_key) = (ds~load_uint(32), ds~load_uint(32), ds~load_uint(256));
throw_unless(34, subwallet_id == stored_subwallet);

We will need to add the above value to the initial data of the contract, so the variable needs to be saved as follows:

const subWallet = 698983191;

Compiling Wallet Code

Now that we have the private and public keys and the subwallet_id clearly defined we need to compile the wallet code. To accomplish this, we’ll use the wallet v3 code from the official repository.

To compile wallet code it is necessary to use the @ton-community/func-js library. Using this library it allows us to compile FunC code and retrieve a cell containing the code. To get started, it is necessary to install the library and save (--save) it to the package.json as follows:

npm i --save @ton-community/func-js

We’ll only use JavaScript to compile code, as the libraries for compiling code are JavaScript based. However, after compiling is finalized, as long as we have the base64 output of our cell, it is possible to use this compiled code in languages such as Go and others.

First, we need to create two files: wallet_v3.fc and stdlib.fc. The compiler works with the stdlib.fc library. All necessary and basic functions, which correspond with the asm instructions were created in the library. The stdlib.fc file can be downloaded here. In the wallet_v3.fc file it is necessary to copy the code above.

Now we have the following structure for the project we are creating:

.
├── src/
│ ├── main.ts
│ ├── wallet_v3.fc
│ └── stdlib.fc
├── nodemon.json
├── package-lock.json
├── package.json
└── tsconfig.json
info

It’s fine if your IDE plugin conflicts with the () set_seed(int) impure asm "SETRAND"; in the stdlib.fc file.

Remember to add the following line to the beginning of the wallet_v3.fc file to indicate that the functions from the stdlib will be used below:

#include "stdlib.fc";

Now let’s write code to compile our smart contract and run it using the npm run start:dev:

import { compileFunc } from '@ton-community/func-js';
import fs from 'fs'; // we use fs for reading content of files
import { Cell } from '@ton/core';

const result = await compileFunc({
targets: ['wallet_v3.fc'], // targets of your project
sources: {
"stdlib.fc": fs.readFileSync('./src/stdlib.fc', { encoding: 'utf-8' }),
"wallet_v3.fc": fs.readFileSync('./src/wallet_v3.fc', { encoding: 'utf-8' }),
}
});

if (result.status === 'error') {
console.error(result.message)
return;
}

const codeCell = Cell.fromBoc(Buffer.from(result.codeBoc, "base64"))[0]; // get buffer from base64 encoded BOC and get cell from this buffer

// now we have base64 encoded BOC with compiled code in result.codeBoc
console.log('Code BOC: ' + result.codeBoc);
console.log('\nHash: ' + codeCell.hash().toString('base64')); // get the hash of cell and convert in to base64 encoded string. We will need it further

The result will be the following output in the terminal:

Code BOC: te6ccgEBCAEAhgABFP8A9KQT9LzyyAsBAgEgAgMCAUgEBQCW8oMI1xgg0x/TH9MfAvgju/Jj7UTQ0x/TH9P/0VEyuvKhUUS68qIE+QFUEFX5EPKj+ACTINdKltMH1AL7AOgwAaTIyx/LH8v/ye1UAATQMAIBSAYHABe7Oc7UTQ0z8x1wv/gAEbjJftRNDXCx+A==

Hash: idlku00WfSC36ujyK2JVT92sMBEpCNRUXOGO4sJVBPA=

Once this is completed it is possible to retrieve the same cell (using the base64 encoded output) with our wallet code using other libraries and languages:

import (
"encoding/base64"
"github.com/xssnick/tonutils-go/tvm/cell"
)

base64BOC := "te6ccgEBCAEAhgABFP8A9KQT9LzyyAsBAgEgAgMCAUgEBQCW8oMI1xgg0x/TH9MfAvgju/Jj7UTQ0x/TH9P/0VEyuvKhUUS68qIE+QFUEFX5EPKj+ACTINdKltMH1AL7AOgwAaTIyx/LH8v/ye1UAATQMAIBSAYHABe7Oc7UTQ0z8x1wv/gAEbjJftRNDXCx+A==" // save our base64 encoded output from compiler to variable
codeCellBytes, _ := base64.StdEncoding.DecodeString(base64BOC) // decode base64 in order to get byte array
codeCell, err := cell.FromBOC(codeCellBytes) // get cell with code from byte array
if err != nil { // check if there are any error
panic(err)
}

log.Println("Hash:", base64.StdEncoding.EncodeToString(codeCell.Hash())) // get the hash of our cell, encode it to base64 because it has []byte type and output to the terminal

The result will be the following output in the terminal:

idlku00WfSC36ujyK2JVT92sMBEpCNRUXOGO4sJVBPA=

After the above processes are complete it is confirmed that the correct code is being used within our cell because the hashes match.

Creating the State Init for Deployment

Before building a transaction it is important to understand what a State Init is. First let’s go through the TL-B scheme:

OptionExplanation
split_depthThis option is intended for highly loaded smart contracts that can be split and located on several shardchains. More information detailing how this works can be found in the tblkch.pdf (4.1.6). Only a 0 bit is stored since it is being used only within a wallet smart contract.
specialUsed for TicTok. These smart contracts are automatically called for each block and are not needed for regular smart contracts. Information about this can be found in this section or in tblkch.pdf (4.1.6). Only a 0 bit is stored within this specification because we do not need such a function.
code1 bit means the presence of the smart contract code as a reference.
data1 bit means the presence of the smart contract data as a reference.
libraryA library that operates on the masterchain and can be used by different smart contracts. This will not be used for wallet, so its bit is set to 0. Information about this can be found in tblkch.pdf (1.8.4).

Next we’ll prepare the initial data, which will be present in our contract’s storage immediately after deployment:

import { beginCell } from '@ton/core';

const dataCell = beginCell().
storeUint(0, 32). // Seqno
storeUint(698983191, 32). // Subwallet ID
storeBuffer(keyPair.publicKey). // Public Key
endCell();

At this stage, both the contract code and its initial data is present. With this data, we can produce our wallet address. The address of the wallet depends on the State Init, which includes the code and initial data.

import { Address } from '@ton/core';

const stateInit = beginCell().
storeBit(0). // No split_depth
storeBit(0). // No special
storeBit(1). // We have code
storeRef(codeCell).
storeBit(1). // We have data
storeRef(dataCell).
storeBit(0). // No library
endCell();

const contractAddress = new Address(0, stateInit.hash()); // get the hash of stateInit to get the address of our smart contract in workchain with ID 0
console.log(`Contract address: ${contractAddress.toString()}`); // Output contract address to console

Using the State Init, we can now build the transaction and send it to the blockchain. To carry out this process a minimum wallet balance of 0.1 TON (the balance can be less, but this amount is guaranteed to be sufficient) is required. To accomplish this, we’ll need to run the code mentioned earlier in the tutorial, get the correct wallet address and send 0.1 TON to this address.

Let’s start with building the transaction similar to the one we built in the previous section:

import { sign } from '@ton/crypto';
import { toNano } from '@ton/core';

const internalMessageBody = beginCell().
storeUint(0, 32).
storeStringTail("Hello, TON!").
endCell();

const internalMessage = beginCell().
storeUint(0x10, 6). // no bounce
storeAddress(Address.parse("put your first wallet address from were you sent 0.1 TON")).
storeCoins(toNano("0.03")).
storeUint(1, 1 + 4 + 4 + 64 + 32 + 1 + 1). // We store 1 that means we have body as a reference
storeRef(internalMessageBody).
endCell();

// transaction for our wallet
const toSign = beginCell().
storeUint(subWallet, 32).
storeUint(Math.floor(Date.now() / 1e3) + 60, 32).
storeUint(0, 32). // We put seqno = 0, because after deploying wallet will store 0 as seqno
storeUint(3, 8).
storeRef(internalMessage);

const signature = sign(toSign.endCell().hash(), keyPair.secretKey);
const body = beginCell().
storeBuffer(signature).
storeBuilder(toSign).
endCell();

After this is completed the result is the correct State Init and Message Body.

Sending An External Transaction

The main difference will be in the presence of the external message, because the State Init is stored to help carry out correct contract deployment. Since the contract does not have its own code yet, it cannot process any internal messages. Therefore, next we send its code and the initial data after it is successfully deployed so it can process our message with "Hello, TON!" comment:

const externalMessage = beginCell().
storeUint(0b10, 2). // indicate that it is an incoming external transaction
storeUint(0, 2). // src -> addr_none
storeAddress(contractAddress).
storeCoins(0). // Import fee
storeBit(1). // We have State Init
storeBit(1). // We store State Init as a reference
storeRef(stateInit). // Store State Init as a reference
storeBit(1). // We store Message Body as a reference
storeRef(body). // Store Message Body as a reference
endCell();

Finally, we can send our transaction to the blockchain to deploy our wallet and use it.

import { TonClient } from '@ton/ton';

const client = new TonClient({
endpoint: "https://toncenter.com/api/v2/jsonRPC",
apiKey: "put your api key" // you can get an api key from @tonapibot bot in Telegram
});

client.sendFile(externalMessage.toBoc());

Note that we have sent an internal message using mode 3. If it is necessary to repeat the deployment of the same wallet, the smart contract can be destroyed. To accomplish this, set the mode correctly by adding 128 (take the entire balance of the smart contract) + 32 (destroy the smart contract) which will = 160 to retrieve the remaining TON balance and deploy the wallet again.

It's important to note that for each new transaction the seqno will need to be increased by one.

info

The contract code we used is verified, so you can see an example here.

💸 Working With Wallet Smart Contracts

After completing the first half of this tutorial we’re now much more familiar with wallet smart contracts and how they are developed and used. We learned how to deploy and destroy them and send messages without depending on pre-configured library functions. To apply more of what we learned above, in the next section, we’ll focus on building and sending more complex messages.

Sending Multiple Messages Simultaneously

As you may already know, one cell can store up to 1023 bits of data and up to 4 references to other cells. In the first section of this tutorial we detailed how internal messages are delivered in a ‘whole’ loop as a link and sent. This means it is possible to store up to 4 internal messages inside the external message. This allows four transactions to be sent at the same time.

To accomplish this, it is necessary to create 4 different internal messages. We can do this manually or through a loop. We need to define 3 arrays: array of TON amount, array of comments, array of messages. For messages, we need to prepare another one array - internalMessages.

import { Cell } from '@ton/core';

const internalMessagesAmount = ["0.01", "0.02", "0.03", "0.04"];
const internalMessagesComment = [
"Hello, TON! #1",
"Hello, TON! #2",
"", // Let's leave the third transaction without comment
"Hello, TON! #4"
]
const destinationAddresses = [
"Put any address that belongs to you",
"Put any address that belongs to you",
"Put any address that belongs to you",
"Put any address that belongs to you"
] // All 4 addresses can be the same

let internalMessages:Cell[] = []; // array for our internal messages

Sending mode for all messages is set to mode 3. However, if different modes are required an array can be created to fulfill different purposes.

import { Address, beginCell, toNano } from '@ton/core';

for (let index = 0; index < internalMessagesAmount.length; index++) {
const amount = internalMessagesAmount[index];

let internalMessage = beginCell().
storeUint(0x18, 6). // bounce
storeAddress(Address.parse(destinationAddresses[index])).
storeCoins(toNano(amount)).
storeUint(0, 1 + 4 + 4 + 64 + 32 + 1);

/*
At this stage, it is not clear if we will have a message body.
So put a bit only for stateInit, and if we have a comment, in means
we have a body message. In that case, set the bit to 1 and store the
body as a reference.
*/

if(internalMessagesComment[index] != "") {
internalMessage.storeBit(1) // we store Message Body as a reference

let internalMessageBody = beginCell().
storeUint(0, 32).
storeStringTail(internalMessagesComment[index]).
endCell();

internalMessage.storeRef(internalMessageBody);
}
else
/*
Since we do not have a message body, we indicate that
the message body is in this message, but do not write it,
which means it is absent. In that case, just set the bit to 0.
*/
internalMessage.storeBit(0);

internalMessages.push(internalMessage.endCell());
}

Now let's use our knowledge from chapter two to build a transaction for our wallet that can send 4 transactions simultaneously:

import { TonClient } from '@ton/ton';
import { mnemonicToWalletKey } from '@ton/crypto';

const walletAddress = Address.parse('put your wallet address');
const client = new TonClient({
endpoint: "https://toncenter.com/api/v2/jsonRPC",
apiKey: "put your api key" // you can get an api key from @tonapibot bot in Telegram
});

const mnemonic = 'put your mnemonic'; // word1 word2 word3
let getMethodResult = await client.runMethod(walletAddress, "seqno"); // run "seqno" GET method from your wallet contract
let seqno = getMethodResult.stack.readNumber(); // get seqno from response

const mnemonicArray = mnemonic.split(' '); // get array from string
const keyPair = await mnemonicToWalletKey(mnemonicArray); // get Secret and Public keys from mnemonic

let toSign = beginCell().
storeUint(698983191, 32). // subwallet_id
storeUint(Math.floor(Date.now() / 1e3) + 60, 32). // Transaction expiration time, +60 = 1 minute
storeUint(seqno, 32); // store seqno
// Do not forget that if we use Wallet V4, we need to add storeUint(0, 8).

Next, we’ll add our messages that we built earlier in the loop:

for (let index = 0; index < internalMessages.length; index++) {
const internalMessage = internalMessages[index];
toSign.storeUint(3, 8) // store mode of our internal transaction
toSign.storeRef(internalMessage) // store our internalMessage as a reference
}

Now that the above processes are complete, let’s sign our message, build an external message (as outlined in previous sections of this tutorial) and send it to the blockchain:

import { sign } from '@ton/crypto';

let signature = sign(toSign.endCell().hash(), keyPair.secretKey); // get the hash of our message to wallet smart contract and sign it to get signature

let body = beginCell().
storeBuffer(signature). // store signature
storeBuilder(toSign). // store our message
endCell();

let externalMessage = beginCell().
storeUint(0b10, 2). // ext_in_msg_info$10
storeUint(0, 2). // src -> addr_none
storeAddress(walletAddress). // Destination address
storeCoins(0). // Import Fee
storeBit(0). // No State Init
storeBit(1). // We store Message Body as a reference
storeRef(body). // Store Message Body as a reference
endCell();

client.sendFile(externalMessage.toBoc());
Connection error

If an error related to the lite-server connection (Golang) occurs, the code must be run until the transaction can be sent. This is because the tonutils-go library uses several different lite-servers through the global configuration that have been specified in the code. However, not all lite-servers can accept our connection.

After this process is completed it is possible to use a TON blockchain explorer to verify that the wallet sent four transactions to the addresses previously specified.

NFT Transfers

In addition to regular transactions, users often send NFTs to each other. Unfortunately, not all libraries contain methods that are tailored for use with this type of smart contract. Therefore, it is necessary to create code that will allow us to build a transaction for sending NFTs. First, let's become more familiar with the TON NFT standard.

Especially, we need to understand TL-B for NFT Transfers in details.

  • query_id: Query ID has no value in terms of transaction processing. The NFT contract doesn't validate it; it only reads it. This value can be useful when a service wants to assign a specific query ID to each of its transactions for identification purposes. Therefore, we will set it to 0.

  • response_destination: After processing the ownership change transaction there will be extra TON. They will be sent to this address, if specified, otherwise remain on the NFT balance.

  • custom_payload: The custom_payload is needed to carry out specific tasks and is not used with ordinary NFTs.

  • forward_amount: If the forward_amount isn’t zero, the specified TON amount will be sent to the new owner. That way the new owner will be notified that they received something.

  • forward_payload: The forward_payload is additional data that can be sent to the new owner together with the forward_amount. For example, using forward_payload allows users to add a comment during the transfer of the NFT, as shown in the tutorial earlier. However, although the forward_payload is written within TON’s NFT standard, blockchain explorers do not fully support displaying various details. The same problem also exists when displaying Jettons.

Now let's build the transaction itself:

import { Address, beginCell, toNano } from '@ton/core';

const destinationAddress = Address.parse("put your wallet where you want to send NFT");
const walletAddress = Address.parse("put your wallet which is the owner of NFT")
const nftAddress = Address.parse("put your nft address");

// We can add a comment, but it will not be displayed in the explorers,
// as it is not supported by them at the time of writing the tutorial.
const forwardPayload = beginCell().
storeUint(0, 32).
storeStringTail("Hello, TON!").
endCell();

const transferNftBody = beginCell().
storeUint(0x5fcc3d14, 32). // Opcode for NFT transfer
storeUint(0, 64). // query_id
storeAddress(destinationAddress). // new_owner
storeAddress(walletAddress). // response_destination for excesses
storeBit(0). // we do not have custom_payload
storeCoins(toNano("0.01")). // forward_amount
storeBit(1). // we store forward_payload as a reference
storeRef(forwardPayload). // store forward_payload as a reference
endCell();

const internalMessage = beginCell().
storeUint(0x18, 6). // bounce
storeAddress(nftAddress).
storeCoins(toNano("0.05")).
storeUint(1, 1 + 4 + 4 + 64 + 32 + 1 + 1). // We store 1 that means we have body as a reference
storeRef(transferNftBody).
endCell();

The NFT transfer opcode comes from the same standard. Now let's complete the transaction, as is laid out in the previous sections of this tutorial. The correct code needed to complete the transaction is found in the GitHub repository.

The same procedure can be completed with Jettons. To conduct this process, read the TL-B standart for jettons transfer. To this point specifically, a small difference between NFT and Jettons transfers exists.

Wallet v3 and Wallet v4 Get Methods

Smart contracts often make use of GET methods, however, they don’t run inside the blockchain but instead on the client side. GET methods have many uses and provide accessibility to different data types for smart contracts. For example, the get_nft_data() method in NFT smart contracts allows users to retrieve specific content, owner, and NFT collection information.

Below we’ll learn more about the basics of GET methods used with V3 and V4. Let’s start with the methods that are the same for both wallet versions:

MethodExplanation
int seqno()This method is needed to receive the current seqno and send transactions with the correct value. In previous sections of this tutorial, this method was called often.
int get_public_key()This method is used to retrive a public key. The get_public_key() is not broadly used, and can be used by different services. For example, some API services allow for the retrieval of numerous wallets with the same public key

Now let’s move to the methods that only the V4 wallet makes use of:

MethodExplanation
int get_subwallet_id()Earlier in the tutorial we considered this. This method allows you to retrive subwallet_id.
int is_plugin_installed(int wc, int addr_hash)Let’s us know if the plugin has been installed. To call this method it’s necessary to pass the workchain and the plugin address hash.
tuple get_plugin_list()This method returns the address of the plugins that are installed.

Let’s consider the get_public_key and the is_plugin_installed methods. These two methods were chosen because at first we would have to get a public key from 256 bits of data, and after that we would have to learn how to pass a slice and different types of data to GET methods. This is very useful to help us learn how to properly make use of these methods.

First we need a client that is capable of sending requests. Therefore, we’ll use a specific wallet address (EQDKbjIcfM6ezt8KjKJJLshZJJSqX7XOA4ff-W72r5gqPrHF) as an example:

import { TonClient } from '@ton/ton';
import { Address } from '@ton/core';

const client = new TonClient({
endpoint: "https://toncenter.com/api/v2/jsonRPC",
apiKey: "put your api key" // you can get an api key from @tonapibot bot in Telegram
});

const walletAddress = Address.parse("EQDKbjIcfM6ezt8KjKJJLshZJJSqX7XOA4ff-W72r5gqPrHF"); // my wallet address as an example

Now we need to call the GET method wallet.

// I always call runMethodWithError instead of runMethod to be able to check the exit_code of the called method. 
let getResult = await client.runMethodWithError(walletAddress, "get_public_key"); // run get_public_key GET Method
const publicKeyUInt = getResult.stack.readBigNumber(); // read answer that contains uint256
const publicKey = publicKeyUInt.toString(16); // get hex string from bigint (uint256)
console.log(publicKey)

After the call is successfully completed the end result is an extremely large 256 bit number which must be translated into a hex string. The resulting hex string for the wallet address we provided above is as follows: 430db39b13cf3cb76bfa818b6b13417b82be2c6c389170fbe06795c71996b1f8. Next, we leverage the TonAPI (/v1/wallet/findByPubkey method), by inputting the obtained hex string into the system and it is immediately clear that the first element in the array within the answer will identify my wallet.

Then we switch to the is_plugin_installed method. As an example, we’ll again use the wallet we used earlier (EQAM7M--HGyfxlErAIUODrxBA3yj5roBeYiTuy6BHgJ3Sx8k) and the plugin (EQBTKTis-SWYdupy99ozeOvnEBu8LRrQP_N9qwOTSAy3sQSZ):

const oldWalletAddress = Address.parse("EQAM7M--HGyfxlErAIUODrxBA3yj5roBeYiTuy6BHgJ3Sx8k"); // my old wallet address
const subscriptionAddress = Address.parseFriendly("EQBTKTis-SWYdupy99ozeOvnEBu8LRrQP_N9qwOTSAy3sQSZ"); // subscription plugin address which is already installed on the wallet

Now we need to retrieve the plugin’s hash address so the address can be translated into a number and sent to the GET Method.

const hash = BigInt(`0x${subscriptionAddress.address.hash.toString("hex")}`) ;

getResult = await client.runMethodWithError(oldWalletAddress, "is_plugin_installed",
[
{type: "int", value: BigInt("0")}, // pass workchain as int
{type: "int", value: hash} // pass plugin address hash as int
]);
console.log(getResult.stack.readNumber()); // -1

The response must be -1, meaning the result is true. It is also possible to send a slice and a cell if required. It would be enough to create a Slice or Cell and transfer it instead of using the BigInt, specifying the appropriate type.

Contract Deployment via Wallet

In chapter three, we deployed a wallet. To accomplish this, we initially sent some TON and then a transaction from the wallet to deploy a smart contract. However, this process is not broadly used with external transactions and is often primarily used for wallets only. While developing contracts, the deployment process is initialized by sending internal messages.

To accomplish this, will use the V3R2 wallet smart contract that was used in the third chapter. In this case, we’ll set the subwallet_id to 3 or any other number needed to retrieve another address when using the same private key (it's changeable):

import { beginCell, Cell } from '@ton/core';
import { mnemonicToWalletKey } from '@ton/crypto';

const mnemonicArray = 'put your mnemonic'.split(" ");
const keyPair = await mnemonicToWalletKey(mnemonicArray); // extract private and public keys from mnemonic

const codeCell = Cell.fromBase64('te6ccgEBCAEAhgABFP8A9KQT9LzyyAsBAgEgAgMCAUgEBQCW8oMI1xgg0x/TH9MfAvgju/Jj7UTQ0x/TH9P/0VEyuvKhUUS68qIE+QFUEFX5EPKj+ACTINdKltMH1AL7AOgwAaTIyx/LH8v/ye1UAATQMAIBSAYHABe7Oc7UTQ0z8x1wv/gAEbjJftRNDXCx+A==');
const dataCell = beginCell().
storeUint(0, 32). // Seqno
storeUint(3, 32). // Subwallet ID
storeBuffer(keyPair.publicKey). // Public Key
endCell();

const stateInit = beginCell().
storeBit(0). // No split_depth
storeBit(0). // No special
storeBit(1). // We have code
storeRef(codeCell).
storeBit(1). // We have data
storeRef(dataCell).
storeBit(0). // No library
endCell();

Next we’ll retrieve the address from our contract and build the InternalMessage. Also we add the "Deploying..." comment to our transaction.

import { Address, toNano } from '@ton/core';

const contractAddress = new Address(0, stateInit.hash()); // get the hash of stateInit to get the address of our smart contract in workchain with ID 0
console.log(`Contract address: ${contractAddress.toString()}`); // Output contract address to console

const internalMessageBody = beginCell().
storeUint(0, 32).
storeStringTail('Deploying...').
endCell();

const internalMessage = beginCell().
storeUint(0x10, 6). // no bounce
storeAddress(contractAddress).
storeCoins(toNano('0.01')).
storeUint(0, 1 + 4 + 4 + 64 + 32).
storeBit(1). // We have State Init
storeBit(1). // We store State Init as a reference
storeRef(stateInit). // Store State Init as a reference
storeBit(1). // We store Message Body as a reference
storeRef(internalMessageBody). // Store Message Body Init as a reference
endCell();
info

Note that above, the bits have been specified and that the stateInit and internalMessageBody have been saved as references. Since the links are stored separately, we could write 4 (0b100) + 2 (0b10) + 1 (0b1) -> (4 + 2 + 1, 1 + 4 + 4 + 64 + 32 + 1 + 1 + 1) which means (0b111, 1 + 4 + 4 + 64 + 32 + 1 + 1 + 1) and then save two references.

Next, we’ll prepare a message for our wallet and send it:

import { TonClient } from '@ton/ton';
import { sign } from '@ton/crypto';

const client = new TonClient({
endpoint: 'https://toncenter.com/api/v2/jsonRPC',
apiKey: 'put your api key' // you can get an api key from @tonapibot bot in Telegram
});

const walletMnemonicArray = 'put your mnemonic'.split(' ');
const walletKeyPair = await mnemonicToWalletKey(walletMnemonicArray); // extract private and public keys from mnemonic
const walletAddress = Address.parse('put your wallet address with which you will deploy');
const getMethodResult = await client.runMethod(walletAddress, 'seqno'); // run "seqno" GET method from your wallet contract
const seqno = getMethodResult.stack.readNumber(); // get seqno from response

// transaction for our wallet
const toSign = beginCell().
storeUint(698983191, 32). // subwallet_id
storeUint(Math.floor(Date.now() / 1e3) + 60, 32). // Transaction expiration time, +60 = 1 minute
storeUint(seqno, 32). // store seqno
// Do not forget that if we use Wallet V4, we need to add storeUint(0, 8).
storeUint(3, 8).
storeRef(internalMessage);

const signature = sign(toSign.endCell().hash(), walletKeyPair.secretKey); // get the hash of our message to wallet smart contract and sign it to get signature
const body = beginCell().
storeBuffer(signature). // store signature
storeBuilder(toSign). // store our message
endCell();

const external = beginCell().
storeUint(0b10, 2). // indicate that it is an incoming external transaction
storeUint(0, 2). // src -> addr_none
storeAddress(walletAddress).
storeCoins(0). // Import fee
storeBit(0). // We do not have State Init
storeBit(1). // We store Message Body as a reference
storeRef(body). // Store Message Body as a reference
endCell();

console.log(external.toBoc().toString('base64'));
client.sendFile(external.toBoc());

This concludes our work with ordinary wallets. At this stage, you should have a strong understanding of how to interact with wallet smart contracts, send transactions, and be able to use various library types.

🔥 High-Load Wallets

In some situations, sending a large number of transactions per message may be necessary. As previously mentioned, ordinary wallets support sending up to 4 transactions at a time by storing a maximum of 4 references in a single cell. High-load wallets only allow 255 transactions to be sent at once. This restriction exists because the maximum number of outgoing messages (actions) in the blockchain’s config settings is set to 255.

Exchanges are probably the best example of where high-load wallets are used on a large scale. Established exchanges like Binance and others have extremely large user bases, this means that a large number of transaction withdrawals are processed in short time periods. High-load wallets help address these withdrawal requests.

High-load wallet FunC code

First, let’s examine the code structure of high-load wallet smart contract:

() recv_external(slice in_msg) impure {
var signature = in_msg~load_bits(512); ;; get signature from the message body
var cs = in_msg;
var (subwallet_id, query_id) = (cs~load_uint(32), cs~load_uint(64)); ;; get rest values from the message body
var bound = (now() << 32); ;; bitwise left shift operation
throw_if(35, query_id < bound); ;; throw an error if transaction has expired
var ds = get_data().begin_parse();
var (stored_subwallet, last_cleaned, public_key, old_queries) = (ds~load_uint(32), ds~load_uint(64), ds~load_uint(256), ds~load_dict()); ;; read values from storage
ds.end_parse(); ;; make sure we do not have anything in ds
(_, var found?) = old_queries.udict_get?(64, query_id); ;; check if we have already had such a request
throw_if(32, found?); ;; if yes throw an error
throw_unless(34, subwallet_id == stored_subwallet);
throw_unless(35, check_signature(slice_hash(in_msg), signature, public_key));
var dict = cs~load_dict(); ;; get dictionary with messages
cs.end_parse(); ;; make sure we do not have anything in cs
accept_message();

💡 Useful links:

"Bitwise operations" in docs

"load_dict()" in docs

"udict_get?()" in docs

You notice some differences from ordinary wallets. Now let’s take a closer look at more details of how high-load wallets work on TON (except subwallets as we have gone over this previously).

Using a Query ID In Place Of a Seqno

As we previously discussed, ordinary wallet seqno increase by 1 after each transaction. While using a wallet sequence we had to wait until this value was updated, then retrieve it using the GET method and send a new transaction. This process takes a significant amount of time which high-load wallets are not designed for (as discussed above, they are meant to send a large number of transactions very quickly). Therefore, high-load wallets on TON make use of the query_id.

If the same transaction request already exists, the contract won’t accept it, as it has already been processed:

var (stored_subwallet, last_cleaned, public_key, old_queries) = (ds~load_uint(32), ds~load_uint(64), ds~load_uint(256), ds~load_dict()); ;; read values from storage
ds.end_parse(); ;; make sure we do not have anything in ds
(_, var found?) = old_queries.udict_get?(64, query_id); ;; check if we have already had such a request
throw_if(32, found?); ;; if yes throw an error

This way, we are being protected from repeat transactions, which was the role of seqno in ordinary wallets.

Sending Transactions

After the contract has accepted the external message, a loop starts, in which the slices stored in the dictionary are taken. These slices store transaction modes and the transactions themselves. Sending new transactions takes place until the dictionary is empty.

int i = -1; ;; we write -1 because it will be the smallest value among all dictionary keys
do {
(i, var cs, var f) = dict.idict_get_next?(16, i); ;; get the key and its corresponding value with the smallest key, which is greater than i
if (f) { ;; check if any value was found
var mode = cs~load_uint(8); ;; load transaction mode
send_raw_message(cs~load_ref(), mode); ;; load transaction itself and send it
}
} until (~ f); ;; if any value was found continue

💡 Useful link:

"idict_get_next()" in docs

Note that if a value is found, f is always equal to -1 (true). The ~ -1 operation (bitwise not) will always return a value of 0, meaning that the loop should be continued. At the same time, when a dictionary is filled with transactions, it is necessary to start calculating those with a value greater than -1 (e.g., 0) and continue increasing the value by 1 with each transaction. This structure allows transactions to be sent in the correct sequential order.

Removing Expired Queries

Typically, smart contracts on TON pay for their own storage. This means that the amount of data smart contracts can store is limited to prevent high network transaction fees. To allow the system to be more efficient, transactions that are more than 64 seconds old are removed from the storage. This is conducted as follows:

bound -= (64 << 32);   ;; clean up records that have expired more than 64 seconds ago
old_queries~udict_set_builder(64, query_id, begin_cell()); ;; add current query to dictionary
var queries = old_queries; ;; copy dictionary to another variable
do {
var (old_queries', i, _, f) = old_queries.udict_delete_get_min(64);
f~touch();
if (f) { ;; check if any value was found
f = (i < bound); ;; check if more than 64 seconds have elapsed after expiration
}
if (f) {
old_queries = old_queries'; ;; if yes save changes in our dictionary
last_cleaned = i; ;; save last removed query
}
} until (~ f);

💡 Useful link:

"udict_delete_get_min()" in docs

Note that it is necessary to interact with the f variable several times. Since the TVM is a stack machine, during each interaction with the f variable it is necessary to pop all values to get the desired variable. The f~touch() operation places the f variable at the top of the stack to optimize code execution.

Bitwise Operations

This section may seem a bit complicated for those who have not previously worked with bitwise operations. The following line of code can be seen in the smart contract code:

var bound = (now() << 32); ;; bitwise left shift operation

As a result 32 bits are added to the number on the right side. This means that existing values are moved 32 bits to the left. For example, let’s consider the number 3 and translate it into a binary form with a result of 11. Applying the 3 << 2 operation, 11 is moved 2 bit places. This means that two bits are added to the right of the string. In the end, we have 1100, which is 12.

The first thing to understand about this process is to remember that the now() function returns a result of uint32, meaning that the resulting value will be 32 bits. By shifting 32 bits to the left, space is opened up for another uint32, resulting in the correct query_id. This way, the timestamp and query_id can be combined within one variable for optimization.

Next, let’s consider the following line of code:

bound -= (64 << 32); ;; clean up the records that have expired more than 64 seconds ago

Above we performed an operation to shift the number 64 by 32 bits to subtract 64 seconds from our timestamp. This way we'll be able to compare past query_ids and see if they are less than the received value. If so, they expired more than 64 seconds ago:

if (f) { ;; check if any value has been found
f = (i < bound); ;; check if more than 64 seconds have elapsed after expiration
}

To understand this better, let’s use the number 1625918400 as an example of a timestamp. Its binary representation (with the left-handed addition of zeros for 32 bits) is 01100000111010011000101111000000. By performing a 32 bit bitwise left shift, the result is 32 zeros at the end of the binary representation of our number.

After this is completed, it is possible to add any query_id (uint32). Then by subtracting 64 << 32 the result is a timestamp that 64 seconds ago had the same query_id. This fact can be verified by performing the following calculations ((1625918400 << 32) - (64 << 32)) >> 32. This way we can compare the necessary portions of our number (the timestamp) and at the same time the query_id does not interfere.

Storage Updates

After all operations are complete, the only task remaining is to save the new values in the storage:

  set_data(begin_cell()
.store_uint(stored_subwallet, 32)
.store_uint(last_cleaned, 64)
.store_uint(public_key, 256)
.store_dict(old_queries)
.end_cell());
}

GET Methods

The last thing we have to consider before we dive into wallet deployment and transaction creation is high-load wallet GET methods:

MethodExplanation
int processed?(int query_id)Notifies the user if a particular request has been processed. This means it returns -1 if the request has been processed and 0 if it has not. Also, this method may return 1 if the answer is unknown since the request is old and no longer stored in the contract.
int get_public_key()Rerive a public key. We have considered this method before.

Let’s look at the int processed?(int query_id) method closely to help us to understand why we need to make use of the last_cleaned:

int processed?(int query_id) method_id {
var ds = get_data().begin_parse();
var (_, last_cleaned, _, old_queries) = (ds~load_uint(32), ds~load_uint(64), ds~load_uint(256), ds~load_dict());
ds.end_parse();
(_, var found) = old_queries.udict_get?(64, query_id);
return found ? true : - (query_id <= last_cleaned);
}

The last_cleaned is retrieved from the storage of the contract and a dictionary of old queries. If the query is found, it is to be returned true, and if not, the expression - (query_id <= last_cleaned). The last_cleaned contains the last removed request with the highest timestamp, as we started with the minimum timestamp when deleting the requests.

This means that if the query_id passed to the method is smaller than the last last_cleaned value, it is impossible to determine whether it was ever in the contract or not. Therefore the query_id <= last_cleaned returns -1 while the minus before this expression changes the answer to 1. If query_id is larger than last_cleaned method, then it has not yet been processed.

Deploying High-Load Wallets

In order to deploy a high-load wallet it is necessary to generate a mnemonic key in advance, which will be used by the user. It is possible to use the same key that was used in previous sections of this tutorial.

To begin the process required to deploy a high-load wallet it's necessary to copy the code of the smart contract to the same directory where the stdlib.fc and wallet_v3 are located and remember to add #include "stdlib.fc"; to the beginning of the code. Next we’ll compile the high-load wallet code like we did in section three:

import { compileFunc } from '@ton-community/func-js';
import fs from 'fs'
import { Cell } from '@ton/core';

const result = await compileFunc({
targets: ['highload_wallet.fc'], // targets of your project
sources: {
'stdlib.fc': fs.readFileSync('./src/stdlib.fc', { encoding: 'utf-8' }),
'highload_wallet.fc': fs.readFileSync('./src/highload_wallet.fc', { encoding: 'utf-8' }),
}
});

if (result.status === 'error') {
console.error(result.message)
return;
}

const codeCell = Cell.fromBoc(Buffer.from(result.codeBoc, 'base64'))[0];

// now we have base64 encoded BOC with compiled code in result.codeBoc
console.log('Code BOC: ' + result.codeBoc);
console.log('\nHash: ' + codeCell.hash().toString('base64')); // get the hash of cell and convert in to base64 encoded string

The result will be the following output in the terminal:

Code BOC: te6ccgEBCQEA5QABFP8A9KQT9LzyyAsBAgEgAgMCAUgEBQHq8oMI1xgg0x/TP/gjqh9TILnyY+1E0NMf0z/T//QE0VNggED0Dm+hMfJgUXO68qIH+QFUEIf5EPKjAvQE0fgAf44WIYAQ9HhvpSCYAtMH1DAB+wCRMuIBs+ZbgyWhyEA0gED0Q4rmMQHIyx8Tyz/L//QAye1UCAAE0DACASAGBwAXvZznaiaGmvmOuF/8AEG+X5dqJoaY+Y6Z/p/5j6AmipEEAgegc30JjJLb/JXdHxQANCCAQPSWb6VsEiCUMFMDud4gkzM2AZJsIeKz

Hash: lJTRzI7fEvBWcaGpugmSEJbrUIEeGSTsZcPGKfu4CBI=

With the above result it is possible to use the base64 encoded output to retrieve the cell with our wallet code in other libraries and languages as follows:

import (
"encoding/base64"
"github.com/xssnick/tonutils-go/tvm/cell"
"log"
)

base64BOC := "te6ccgEBCQEA5QABFP8A9KQT9LzyyAsBAgEgAgMCAUgEBQHq8oMI1xgg0x/TP/gjqh9TILnyY+1E0NMf0z/T//QE0VNggED0Dm+hMfJgUXO68qIH+QFUEIf5EPKjAvQE0fgAf44WIYAQ9HhvpSCYAtMH1DAB+wCRMuIBs+ZbgyWhyEA0gED0Q4rmMQHIyx8Tyz/L//QAye1UCAAE0DACASAGBwAXvZznaiaGmvmOuF/8AEG+X5dqJoaY+Y6Z/p/5j6AmipEEAgegc30JjJLb/JXdHxQANCCAQPSWb6VsEiCUMFMDud4gkzM2AZJsIeKz" // save our base64 encoded output from compiler to variable
codeCellBytes, _ := base64.StdEncoding.DecodeString(base64BOC) // decode base64 in order to get byte array
codeCell, err := cell.FromBOC(codeCellBytes) // get cell with code from byte array
if err != nil { // check if there is any error
panic(err)
}

log.Println("Hash:", base64.StdEncoding.EncodeToString(codeCell.Hash())) // get the hash of our cell, encode it to base64 because it has []byte type and output to the terminal

Now we need to retrieve a cell composed of its initial data, build a State Init, and calculate a high-load wallet address. After studying the smart contract code it became clear that the subwallet_id, last_cleaned, public_key and old_queries are sequentially stored in the storage:

import { Address, beginCell } from '@ton/core';
import { mnemonicToWalletKey } from '@ton/crypto';

const highloadMnemonicArray = 'put your mnemonic that you have generated and saved before'.split(' ');
const highloadKeyPair = await mnemonicToWalletKey(highloadMnemonicArray); // extract private and public keys from mnemonic

const dataCell = beginCell().
storeUint(698983191, 32). // Subwallet ID
storeUint(0, 64). // Last cleaned
storeBuffer(highloadKeyPair.publicKey). // Public Key
storeBit(0). // indicate that the dictionary is empty
endCell();

const stateInit = beginCell().
storeBit(0). // No split_depth
storeBit(0). // No special
storeBit(1). // We have code
storeRef(codeCell).
storeBit(1). // We have data
storeRef(dataCell).
storeBit(0). // No library
endCell();

const contractAddress = new Address(0, stateInit.hash()); // get the hash of stateInit to get the address of our smart contract in workchain with ID 0
console.log(`Contract address: ${contractAddress.toString()}`); // Output contract address to console

Everything we have detailed above follows the same steps as the contract deployment via wallet section. To better analyze the fully functional code, please visit the repository indicated at the beginning of the tutorial where all sources are stored.

Sending High-Load Wallet Transactions

Now let’s program a high-load wallet to send several messages at the same time. For example, let's take 12 transactions per message so that the gas fees are small.

High-load balance

To complete the transaction, the balance of the contract must be at least 0.5 TON.

Each message carry its own comment with code and the destination address will be the wallet from which we deployed:

import { Address, beginCell, Cell, toNano } from '@ton/core';

let internalMessages:Cell[] = [];
const walletAddress = Address.parse('put your wallet address from which you deployed high-load wallet');

for (let i = 0; i < 12; i++) {
const internalMessageBody = beginCell().
storeUint(0, 32).
storeStringTail(`Hello, TON! #${i}`).
endCell();

const internalMessage = beginCell().
storeUint(0x18, 6). // bounce
storeAddress(walletAddress).
storeCoins(toNano('0.01')).
storeUint(0, 1 + 4 + 4 + 64 + 32).
storeBit(0). // We do not have State Init
storeBit(1). // We store Message Body as a reference
storeRef(internalMessageBody). // Store Message Body Init as a reference
endCell();

internalMessages.push(internalMessage);
}

After completing the above process, the result is an array of internal messages. Next, it's necessary to create a dictionary for message storage and prepare and sign the message body. This is completed as follows:

import { Dictionary } from '@ton/core';
import { mnemonicToWalletKey, sign } from '@ton/crypto';
import * as crypto from 'crypto';

const dictionary = Dictionary.empty<number, Cell>(); // create an empty dictionary with the key as a number and the value as a cell
for (let i = 0; i < internalMessages.length; i++) {
const internalMessage = internalMessages[i]; // get our message from an array
dictionary.set(i, internalMessage); // save the message in the dictionary
}

const queryID = crypto.randomBytes(4).readUint32BE(); // create a random uint32 number, 4 bytes = 32 bits
const now = Math.floor(Date.now() / 1000); // get current timestamp
const timeout = 120; // timeout for message expiration, 120 seconds = 2 minutes
const finalQueryID = (BigInt(now + timeout) << 32n) + BigInt(queryID); // get our final query_id
console.log(finalQueryID); // print query_id. With this query_id we can call GET method to check if our request has been processed

const toSign = beginCell().
storeUint(698983191, 32). // subwallet_id
storeUint(finalQueryID, 64).
// Here we create our own method that will save the
// transaction mode and a reference to the transaction
storeDict(dictionary, Dictionary.Keys.Int(16), {
serialize: (src, buidler) => {
buidler.storeUint(3, 8); // save transaction mode, mode = 3
buidler.storeRef(src); // save transaction as reference
},
// We won't actually use this, but this method
// will help to read our dictionary that we saved
parse: (src) => {
let cell = beginCell().
storeUint(src.loadUint(8), 8).
storeRef(src.loadRef()).
endCell();
return cell;
}
}
);

const highloadMnemonicArray = 'put your high-load wallet mnemonic'.split(' ');
const highloadKeyPair = await mnemonicToWalletKey(highloadMnemonicArray); // extract private and public keys from mnemonic
const highloadWalletAddress = Address.parse('put your high-load wallet address');

const signature = sign(toSign.endCell().hash(), highloadKeyPair.secretKey); // get the hash of our message to wallet smart contract and sign it to get signature