Token introspection
Token introspection is an OAuth operation in which a service queries an authorization server about a token’s validity, status, and metadata.
Spring Security in Action, Second Edition
Token introspection is an OAuth protocol operation in which a resource server asks an authorization server whether a token is valid and requests its associated metadata.
- How it is used
- Validates opaque access tokens and supports authorization decisions when the resource server needs current authorization-server knowledge.
- How deep it goes
- Implements registration, property configuration, Spring Security wiring, token acquisition, and protected-endpoint testing.
- Examples
- Uses Spring Security configuration, authorization-server cURL requests, introspection responses, and a protected `/demo` endpoint.
- What you can do after
- Configure Spring Security to validate opaque Bearer tokens through an authorization server and test a protected endpoint.
Read how Spring Security in Action, Second Edition explains token introspection →
Software Security for Developers
Token introspection is a validation process in which a service queries an issuer or authorization server to obtain the status and metadata of a token.
- How it is used
- Validates opaque access tokens when a resource server cannot verify them locally.
- How deep it goes
- Defines the request-response flow and operational drawbacks, but does not specify implementation code or endpoint configuration.
- Examples
- Uses an opaque-token validation exchange and contrasts it with signed-token public-key verification.
- What you can do after
- Apply introspection to validate opaque tokens and evaluate its availability, scaling, exposure, and latency costs.
Read how Software Security for Developers explains token introspection →
Secure APIs
A token introspection endpoint is an authorization-server endpoint that returns metadata about an access token to an authorized client or resource server.
- How it is used
- Supports resource servers that need token metadata or authenticity confirmation, especially when access tokens are opaque.
- How deep it goes
- Defines the endpoint, explains opaque-token and jti use cases, and identifies authentication and signed-response requirements.
- Examples
- Uses opaque-token verification and JWT jti legitimacy checks as concrete scenarios.
- What you can do after
- Operate/configure an authenticated introspection endpoint with signed JWT responses.
Related concepts
- opaque tokenused by · An opaque token is an access token whose contents are not directly interpretable by its recipient, typically requiring server-side validation or lookup.
- revocationused by · Revocation is the invalidation or withdrawal of a previously issued credential, key, certificate, token, or permission before or when its authorization ends.
- resource serverused by · A resource server is a service that hosts protected resources, validates access credentials such as tokens, and enforces authorization for client requests.
- identity provideruses · An identity provider is a system that authenticates users or other entities and supplies identity information or authentication assertions to relying applications and services.
- JSON Web Tokenalternative to · A JSON Web Token is a compact, URL-safe representation of claims encoded as a JSON object and protected by a digital signature, message authentication code, or encryption.
- authorization serveruses · An authorization server is an OAuth component that authenticates clients or resource owners, obtains authorization, and issues credentials such as authorization codes and access tokens.
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