> For the complete documentation index, see [llms.txt](/llms.txt).

# Communicate errors

The Snaps SDK exposes a set of known errors that can be thrown from your Snap code without crashing the Snap. See the [Snaps known errors reference](/snaps/reference/known-errors/) for the full list of errors.

## Import and throw errors[​](#import-and-throw-errors "Direct link to Import and throw errors")

To throw these known errors, first import them from the [@metamask/snaps-sdk](https://github.com/MetaMask/snaps/tree/main/packages/snaps-sdk) package, then throw them where needed. For example:

index.ts

```
import type { OnRpcRequestHandler } from '@metamask/snaps-sdk'
import { MethodNotFoundError } from '@metamask/snaps-sdk'

export const onRpcRequest: OnRpcRequestHandler = async ({ request }) => {
  switch (request.method) {
    case 'hello':
      return 'Hello World!'
    default:
      // Throw a known error to avoid crashing the Snap.
      throw new MethodNotFoundError()
  }
}

```

### Pass data with the error[​](#pass-data-with-the-error "Direct link to Pass data with the error")

The error class constructors exported by `@metamask/snaps-sdk` have the following signature:

```
class SnapJsonRpcError extends SnapError {
  new(message?: string, data?: Record<string, Json>)
}

```

Both parameters are optional. If you don't pass `message`, then a pre-determined message is used. If you don't pass `data`, then an empty object is passed.

`data` can be any JSON-serializable object.

## Detect known errors in dapps[​](#detect-known-errors-in-dapps "Direct link to Detect known errors in dapps")

Known errors are thrown back to the caller as JSON-RPC errors. They have a numeric `code`, a `message` string, and a `data` object.

The [Snaps known errors reference](/snaps/reference/known-errors/) lists all the known errors with their codes and intended usage.

## Example[​](#example "Direct link to Example")

See the [@metamask/error-example-snap](https://github.com/MetaMask/snaps/tree/main/packages/examples/packages/errors)package for a full example of communicating errors.