gRPC
16 UNAUTHENTICATED
The request does not have valid authentication credentials for the operation.
When You See This Code
No credentials were provided, or the provided token/certificate is expired or invalid. Different from PERMISSION_DENIED (code 7), which means authenticated but not authorized.
How to Fix
Provide valid authentication credentials (e.g., refresh the OAuth token, regenerate the API key, or renew the client certificate).
Specification
View RFC / Specification →Cross-Protocol Equivalents
Comparisons
Guides
Choosing the Right HTTP Status Codes for REST APIs
API Design
gRPC Status Codes: A Practical Guide
API Design
Debugging Timeout Errors: 408 and 504
Debugging & Troubleshooting
How to Implement and Handle Rate Limiting (429)
API Design
API Versioning Strategies: URL, Header, and Query Param
API Design
Designing Consistent API Error Responses
API Design
API Keys vs OAuth vs JWT: Choosing the Right Auth Method
Security & Authentication