JWT Decoder Online - Inspect JSON Web Token Header, Payload & Expiry Locally
Decode JSON Web Tokens (JWT) instantly inside your browser, inspect the JOSE algorithm header, payload claims (`sub`, `iss`, `aud`, `exp`, `iat`), and human-readable expiration timestamps locally.
This tool processes your input on your device.
Developer tools
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How to use it
Follow these steps in the workspace above.
- Paste your three-part Base64URL JSON Web Token into the input field.
- Inspect the decoded JSON header (algorithm and token type) and payload claims immediately.
- Verify the `exp` (expiration) and `iat` (issued-at) timestamps or copy the formatted JSON claims.
How it works
A JSON Web Token (JWT, RFC 7519) consists of three Base64URL-encoded segments separated by dots. Because the header and payload are Base64URL-encoded, developers need a fast way to inspect claims like sub (subject), roles, and exp (expiration epoch) when debugging OAuth 2.0, OpenID Connect (OIDC), Auth0, Clerk, Supabase, or NextAuth sessions.
Why Client-Side JWT Decoding Matters
Our JWT Decoder splits and Base64URL-decodes your token 100% locally in browser memory so your session payloads never leave your machine.
- JOSE Header Inspection: Check
alg(e.g., RS256, ES256, HS256) andkid(Key ID) to troubleshoot signature verification mismatches. - Standard Registered Claims: Instantly read
iss(Issuer),sub(Subject),aud(Audience),exp(Expiration Time), andiat(Issued At). Need to convert raw epoch numbers? Open our Unix Timestamp Converter.
