Approaches for data processing are disclosed that include receiving, from a client, an application programming interface (API) request at an API endpoint of an API, where the API endpoint is configured to process data requests at a data plane of the API, identifying, from a header of the API request, a request for metadata associated with the API, redirecting the API request to a metadata plane of the API, retrieving, at the metadata plane of the API, the requested metadata based on the header of the API request, and transmitting, via the API endpoint and to the client, a response message indicating the requested metadata.