OAuth Token Validator — JWT & OIDC Decoder
Validate and inspect OAuth tokens in your browser. Decode JWT access tokens and ID tokens to view claims, scopes, and expiry. Analyse opaque tokens for entropy and format. Free and private.
How to Use OAuth Token Validator — JWT & OIDC Decoder
How to Use the OAuth Token Validator:
Paste Your Token: Copy the OAuth token from your application — this can be a JWT access token, an OIDC ID token, or an opaque bearer token — and paste it into the input field.
Click "Validate Token": The tool detects the token type automatically. JWT tokens (which start with "eyJ" and have three dot-separated parts) are decoded and inspected. All other tokens are treated as opaque.
JWT Tokens — Inspect Claims: For JWT tokens, the tool displays:
- Algorithm from the header (e.g. HS256, RS256, ES256)
- Expiry status — whether the token is currently active or expired
- Scopes — the OAuth scopes granted to the token, shown as coloured badges
- OAuth Claims table — subject (sub), issuer (iss), audience (aud), client ID (client_id or azp), and JWT ID (jti)
- Timing panel — issued-at, not-before, and expires-at in local time
- Full Payload and Header — collapsible JSON panels with copy support
Opaque Tokens — Analyse Format: For non-JWT tokens, the tool shows:
- Token length in characters
- Shannon entropy — a measure of randomness (higher is better; < 3.0 bits/char suggests a sequential or weak token)
- Character set — whether the token uses alphanumeric, base64url, or mixed characters
- A note that opaque tokens must be validated via your authorisation server's introspection endpoint (RFC 7662)
Review Warnings: The tool surfaces issues such as expired tokens, missing scope or issuer claims, and the dangerous "alg: none" case.
Notes:
- Signature verification is not performed — the tool only decodes and analyses the token structure.
- Your token is never sent to any server. All processing happens in your browser.
Frequently Asked Questions
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