# Automatic chain routing for raw EVM transactions

Raw EVM transactions now **automatically route to the correct blockchain** based on the encoded transaction's chain ID. You no longer need to specify a `blockchain` parameter — the platform detects the target chain and routes accordingly.

## What changed

Previously, raw signing on an EVM wallet required a `blockchain` parameter to override the wallet's native chain. Now the platform reads the `chainId` from the RLP-encoded transaction and resolves the target blockchain automatically:

- **Known chain ID** (Ethereum, Arbitrum, Polygon, Base, BNB Chain, Avalanche, 1Money) — the platform routes the transaction to that chain's connector and supports both `signOnly=true` and `signOnly=false`.
- **Unknown chain ID** — the platform treats the transaction as [cross-chain raw signing](/products/wallet/user-interface/transactions/raw-signing#cross-chain-raw-signing-evm): it signs only and requires a policy with a `CHAIN_ID` matcher.


## What's deprecated

The `blockchain` field on the raw transaction request is deprecated. Existing API integrations that send the field continue to work — the platform ignores the value for all raw transactions. EVM transactions route by the chain ID in the encoded transaction; non-EVM transactions always execute on the wallet's native blockchain.

## Example

An Ethereum wallet signing and broadcasting an Arbitrum transaction:


```
POST /v2/vaults/{vaultId}/wallets/{walletId}/transactions/raw
{
  "encodedTransaction": "<RLP-encoded transaction with Arbitrum chainId>",
  "signOnly": false
}
```

You don't need a `blockchain` parameter. The platform extracts the Arbitrum chain ID and routes the transaction to the Arbitrum connector.

## Documentation

- [Automatic chain routing](/products/wallet/user-interface/transactions/raw-signing#automatic-chain-routing-evm)
- [Cross-chain raw signing](/products/wallet/user-interface/transactions/raw-signing#cross-chain-raw-signing-evm)
- [Cross-chain transactions](/products/wallet/user-interface/transactions/cross-chain-transactions)