> ## Documentation Index
> Fetch the complete documentation index at: https://docs.rhino.fi/llms.txt
> Use this file to discover all available pages before exploring further.

# Custom chain adapters

If you need more control over the chain interactions than the included chain adapters provider, you can also implement your own or extend an existing one.

<Warning>
  Implementing and using your own chain adapters can lead to a loss of funds if implemented incorrectly. Please make sure to test your adapter on a testnet thoroughly before using it with real funds.
</Warning>

## Implementing your own custom chain adapter

All you need to implement your own chain adapter is to implement the `ChainAdapter` type exported by the SDK. You can find a list of the required properties in the [chain adapters overview](/sdk/chain-adapters/overview).  It would like something like this:

```typescript theme={null}
import type { ChainAdapter } from '@rhino.fi/sdk'

const customEvmChainAdapter: ChainAdapter = {
  networkId: '',
  getApprovalAmount: () => ...,
  handleTokenApproval: () => ...,
  handleDeposit: () => ...,
  getTokenBalance: () => ...,
  getAllTokenBalances: () => ...,
}
```

## Extending an existing chain adapter

If you only want to tweak a specific aspect of an existing chain adapter, you could simply take one as base and only re-implement some specific functions. Example:

```typescript From provider theme={null}
import { getEvmChainAdapterFromProvider } from '@rhino.fi/sdk/adapters/evm'
import type { ChainAdapter } from '@rhino.fi/sdk'

const evmChainAdapter = getEvmChainAdapterFromProvider(
  provider,
  chainConfig
)

const customEvmChainAdapter: ChainAdapter = {
  ...chainAdapter,
  handleDeposit: (args) => {
    // Your custom bridge deposit function
  }
}
```

<Warning>
  Please check [this section](/contracts/contract-examples) for guidance on how to interact with the Rhino bridge contracts if you plan on implementing a custom bridge deposit function.
</Warning>