Paste a token — the header and payload decode in your browser. Signatures stay server-side where they belong. Safe for production tokens.
JWT
Nothing uploadsValid window
Header
{
"alg": "HS256",
"typ": "JWT"
}Payload
{
"sub": "user-1234",
"name": "Jane Doe",
"iat": 1735050000,
"exp": 9999999999
}Signature
SflKxwRJSMeKKF2QT4fwpMeJf36POk6yJV_adQssw5cSignatures can't be verified client-side without the secret. This tool only decodes — it never tries to send your token anywhere to verify it.
Paste a JWT
Any JWT — access token, id token, refresh — three dot-separated base64url parts.
Read the header + payload
Both get pretty-printed as JSON with a one-click copy.
Check the expiry
iat / nbf / exp claims show absolute timestamps and human-readable relative times.
Never worry about leakage
The tool never sends your token anywhere. No backend, no logging, no analytics on token data.
No — and that's intentional. Signature verification requires the secret or public key, and passing a secret through a third-party website defeats the point. Use your JWT library server-side for verification; use this tool only to inspect claims.
Safer than any hosted decoder. This page runs the decode entirely in your browser — there's no server call, no logging, no analytics event containing the token. That said: if it's a long-lived token, rotate it anyway as a habit.
JWT format is header.payload.signature, each base64url-encoded. The first two are JSON objects; the third is a cryptographic signature over the first two.
Issued-at, not-before, and expiry — standard claims defined in RFC 7519. They're unix timestamps (seconds since epoch). nbf means the token shouldn't be accepted before that time; exp means it expires at that time.
Base64
Encode or decode base64, auto-detecting the direction. Plus an image-to-data-URI mode for inline assets.
JSON formatter
Pretty-print, minify, sort keys, validate — plus one-click TypeScript type inference.
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