JWT Decoder
Paste a JSON Web Token to decode and inspect its header, payload, and signature. Shows expiry date if present. All decoding happens locally — your token never leaves the browser.
Client-side decode only — the signature is not verified. Never paste tokens containing sensitive data into third-party tools.
About JWTs
- A JWT consists of three Base64url-encoded parts separated by dots:
header.payload.signature. - The header typically contains the algorithm (
alg) and token type (typ). - The payload holds claims — standard ones include
sub(subject),iat(issued at),exp(expiration), andiss(issuer). - The signature is used to verify the token — this tool does not verify it.
- Never paste real production tokens into untrusted third-party tools — use this tool only for development tokens.
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