Staking with nominator pools
Overview
With TON smart contracts, you can implement any staking and deposit mechanics you want.
However, there is native staking in TON Blockchain - you can lend Toncoin to validators for staking and share the reward for validation.
The one who lends to validator is called the nominator.
A smart contract, called a nominator pool, provides the ability for one or more nominators to lend Toncoin in a validator stake, and ensures that the validator can use that Toncoin only for validation. This smart contract guarantees the distribution of the reward.
If you are familiar with cryptocurrencies, you must have heard about validators and nominators. Now, the time has come to find out what they are — the two major actors ruling the blockchain.
Validator
A validator is a network node that helps keep the blockchain running by verifying (or validating) suggested blocks and recording them on the blockchain.
To become a validator, you must meet two requirements: have a high-performance server and obtain at least 300,000 Toncoins, in order to make a stake. At the time of writing, there are up to 400 validators per round on TON.
Nominator
New version of nominator pool available, read more in the Single nominator pool and Vesting contract pages.
It's evident that not everyone can afford to have 100,000s of Toncoin on their balance – here's where nominators come into play. Simply put, the nominator is a user who lends his TON to validators. Every time the validator earns a reward by validating blocks, it is distributed between the involved participants.
TON Whales pool allows a minimum deposit of 50 TON. TON Foundation open nominator pool allows users to stake Toncoin in a fully decentralized way, starting with 10,000 TON.
From TON Community post.
There should always be 10 TON on the pool balance - this is the minimum balance for the network storage fee.
Cost per month
Since validation round lasts ~18 hours, takes about 5 TON per validation round and 1 nominator pool takes part in even and odd validation rounds it will take ~105 TON per month to operate the pool.
How to participate?
Source code
The theory of nominators is described in TON Whitepaper, chapters 2.6.3, 2.6.25.