OAuth Token Inspector — Decode & Inspect OAuth Tokens Online Free
Inspect readable JWT access-token claims and recognize opaque tokens locally. No signature verification is performed.
Jump to tool ↓Frequently Asked Questions
Understanding OAuth 2.0 Access Tokens
OAuth 2.0 access tokens are credentials that grant access to protected resources. When a client application requests access to an API, the authorization server issues an access token with specific scopes (permissions) and a limited lifetime. The API validates this token on every request.
Some APIs issue JWT access tokens with claims such as subject, issuer, audience, expiration, and scopes. Others issue opaque tokens. A resource server must use its trusted validation process, including signature and claim checks for JWTs or authorization-server introspection for opaque tokens.
When debugging OAuth flows, the most common issues are: expired tokens (check exp claim), wrong audience (aud must match your API), missing scopes (check scope/scp claim), and incorrect issuer (iss must match your auth server URL). This tool displays decoded claims for troubleshooting; it does not determine whether the token should be accepted.
Standards & References
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