gRPC 2 UNKNOWN vs 3 INVALID_ARGUMENT
Both gRPC 2 (UNKNOWN) and 3 (INVALID_ARGUMENT) belong to the gRPC Status Codes category. 2 indicates that an unknown error occurred. This may be returned when a server raises an exception that doesn't map to any known gRPC status code. Meanwhile, 3 means that the client specified an invalid argument. This indicates arguments that are problematic regardless of the state of the system.
Description
An unknown error occurred. This may be returned when a server raises an exception that doesn't map to any known gRPC status code.
When You See It
The server threw an unhandled exception or returned an error that gRPC couldn't classify into a more specific status code.
How to Fix
Check the server logs for the underlying exception. Wrap server-side errors with explicit gRPC status codes instead of letting them bubble up as UNKNOWN.
Description
The client specified an invalid argument. This indicates arguments that are problematic regardless of the state of the system.
When You See It
A request field failed validation — for example, a negative page size, a malformed email, or a required field left empty.
How to Fix
Inspect the request payload and fix the invalid field. Check the API documentation for expected formats and constraints.
Key Differences
gRPC 2: An unknown error occurred. This may be returned when a server raises an exception that doesn't map to any known gRPC status code.
gRPC 3: The client specified an invalid argument. This indicates arguments that are problematic regardless of the state of the system.
You encounter 2 when the server threw an unhandled exception or returned an error that gRPC couldn't classify into a more specific status code.
You encounter 3 when a request field failed validation — for example, a negative page size, a malformed email, or a required field left empty.
When to Use Which
For 2 (UNKNOWN): Check the server logs for the underlying exception. Wrap server-side errors with explicit gRPC status codes instead of letting them bubble up as UNKNOWN. For 3 (INVALID_ARGUMENT): Inspect the request payload and fix the invalid field. Check the API documentation for expected formats and constraints.