What is kid?

Key ID header parameter — references which key in a JWKS was used to sign the token.

See It in Practice

Paste any JWT into our JWT Decoder to see related claims in action. Use the JWT Debugger for detailed analysis.

Related

Browse the full JWT Glossary or explore JWT Basics.

kid in JWT Authentication

Understanding kid helps you read RFC 7519, debug tokens, and design secure authentication. JWTs combine header, payload claims, and a cryptographic signature.

Browse related resources: JWT Decoder, JWT Validator, JWT Basics, JWT Authentication, JWT Errors, Algorithms, Glossary, and Learning Path.

Try It Now