[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [local‑first/Protocol](https://evolu.dev/docs/api-reference/common/local-first/Protocol) › ProtocolError

```ts
type ProtocolError =
  | ProtocolVersionError
  | ProtocolInvalidDataError
  | ProtocolWriteKeyError
  | ProtocolWriteError
  | ProtocolSyncError
  | ProtocolQuotaError
  | ProtocolTimestampMismatchError;
```

Defined in: [packages/common/src/local-first/Protocol.ts:477](https://github.com/evoluhq/evolu/blob/113517df8a8da4e4eed41363077878e657b22fca/packages/common/src/local-first/Protocol.ts#L477)