# TON Center Emulation API overview (https://docs.ton.org/llms/api/emulate/overview/content.md)



The TON Center Emulation API simulates execution of transactions and traces on the blockchain. Submit an external message or a TON Connect request to inspect the resulting transactions and optional actions.

Emulation **does not** send messages to the blockchain.

## Base URLs [#base-urls]

| Network | Base URL                                       |
| ------- | ---------------------------------------------- |
| Mainnet | `https://toncenter.com/api/emulate/v1`         |
| Testnet | `https://testnet.toncenter.com/api/emulate/v1` |

## Endpoints [#endpoints]

| Category | Method                                                                     | Description                                                                  |
| -------- | -------------------------------------------------------------------------- | ---------------------------------------------------------------------------- |
| Traces   | [`POST /emulateTonConnect`](https://docs.ton.org/llms/api/emulate/traces/emulate-ton-connect-trace/content.md) | Emulate a trace by composing an external message from a TON Connect request. |
| Traces   | [`POST /emulateTrace`](https://docs.ton.org/llms/api/emulate/traces/emulate-trace/content.md)                  | Emulate a trace from an external message serialized as a base64-encoded BoC. |

### Emulating a TON Connect request [#emulating-a-ton-connect-request]

TON Connect emulation accepts one to four internal messages. The sending wallet must be deployed. Supported wallets are `v3r1`, `v3r2`, `v4r1`, `v4r2`, and [`v5r1`](https://docs.ton.org/llms/contracts/standard/wallets/v5/content.md).

Replace `<WALLET_ADDRESS>` with the sending wallet address and `<DESTINATION_ADDRESS>` with the recipient address. The `amount` is a decimal string in nanograms: `1000000000` represents 1 GRAM.

```bash
curl "https://testnet.toncenter.com/api/emulate/v1/emulateTonConnect" \
  -H "Content-Type: application/json" \
  --data '{
    "from": "<WALLET_ADDRESS>",
    "messages": [
      {
        "address": "<DESTINATION_ADDRESS>",
        "amount": "1000000000"
      }
    ],
    "with_actions": true
  }'
```

## Results and options [#results-and-options]

The response includes the masterchain block sequence number, a transaction tree in `trace`, a `transactions` map keyed by hash, and the random seed used for emulation. The boolean `is_incomplete` field indicates whether the trace exceeded the emulation depth limit.

* Set `with_actions` to classify the trace into actions. Use `X-Actions-Version` to select the supported actions version.
* Set `include_code_data` to include contract code and data cells.
* Set `include_address_book` or `include_metadata` to include address book entries or account metadata. These options require server support.
* Set `mc_block_seqno` to select the masterchain state for emulation. If omitted or null, the server uses the latest available state.
* For external-message emulation, set `ignore_chksig` to skip signature checks.

<Callout type="note">
  Shared transaction, trace, action, address book, and metadata models follow [API v3](https://docs.ton.org/llms/api/v3/overview/content.md).
</Callout>