JWT Decoder
Decode and inspect JSON Web Tokens (JWT) instantly. View header, payload, signature, expiry, and claims. 100% client-side, tokens stay local.
What is JWT Decoder?
Decode and inspect JSON Web Tokens (JWTs) entirely in your browser. Paste any eyJ-prefixed token and the tool splits it on the dots, parses the header and payload as syntax-highlighted JSON, and renders standard claims like exp, iat, and nbf as human-readable timestamps. A green Active or red Expired pill tells you token status at a glance - no manual epoch math required. Useful for backend devs debugging auth flows, QA engineers triaging support tickets, and security reviewers auditing JWTs from logs and network captures.
How It Works
Using JWT Decoder in 3 Steps
Paste Your Token
Drop any JWT (eyJ...) into the textarea. The decoder splits it on the dots and parses each segment instantly.
Inspect Header & Payload
Decoded JSON appears in syntax-highlighted blocks with copy buttons. Standard claims like exp, iat, and nbf are surfaced as human-readable timestamps.
Check Expiry at a Glance
A green 'Active' or red 'Expired' pill tells you the token's status without doing math on the exp claim.
Use Cases
Who Uses JWT Decoder?
Backend & Full-Stack Developers
Debug auth flows fast - see what claims your identity provider is actually issuing without spinning up a script.
QA & Support Engineers
Inspect tokens from bug reports to verify expiry, audience, and roles before escalating.
Security Reviewers
Quickly audit JWTs from network captures or logs for sensitive claims that shouldn't be exposed client-side.
FAQ
JWT Decoder — Frequently Asked Questions
Everything you need to know before you start.
Is decoding a JWT the same as verifying it?
No. Decoding only reads the base64url-encoded header and payload, which are not encrypted. Verifying a JWT requires checking the signature against the issuer's secret or public key - a server-side step that this tool intentionally does not perform.
Is it safe to paste my real production JWT here?
Yes. The decoder runs entirely in your browser - your token is never sent to any server, logged, or stored. That said, treat any JWT as a credential and avoid sharing it through screenshots or chat.
Why does the tool say my token is expired?
Standard JWTs include an 'exp' claim with a Unix timestamp. We compare it to your computer's current time. If your clock is wrong or the token is genuinely expired, the badge will turn red.
Which JWT algorithms are supported?
All of them - the decoder treats the algorithm as informational only. HS256, RS256, ES256, EdDSA, and others all decode the same way because the header/payload encoding is identical across algorithms.
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