Free JWT Decoder
Decode and inspect JWT tokens — 100% free in your browser.
Free How to use JWT Decoder
Developer utilities perform pure text transformations—JSON formatting, Base64 encoding, hash generation, JWT decoding, regex testing, and code minification—entirely in JavaScript within your browser. No snippets, tokens, or configuration payloads are sent to a backend because these tools operate on strings already present in the page. That design is ideal when you are inspecting production JWTs, hashing passwords for comparison, or minifying proprietary templates: your input stays in local memory and is discarded when you navigate away. The tools are deterministic and offline-capable once the page has loaded.
What JWT Decoder does and when to use it
JWT Decoder splits JSON Web Tokens into header, payload, and signature segments, base64url-decoding the JSON parts for inspection during OAuth debugging, API integration, and session troubleshooting. Developers verify issuer, audience, and expiry claims without writing throwaway scripts.
Decoding is not verification: seeing a payload does not prove authenticity unless you validate the signature with the correct key. Still, readable claims accelerate diagnosing clock skew, wrong scopes, and misconfigured identity providers.
How this tool works
The tool splits the token on periods, decodes header and payload with base64url rules, and pretty-prints JSON. Signature bytes may be shown hex-encoded; optional HMAC verification can run locally if you supply a secret without sending it to servers.
Tokens pasted into the page remain in memory only for the session. Never decode production tokens on untrusted machines or while screen recording.
Step-by-step instructions
Paste a JWT into the input, decode, and read header algorithm and payload claims such as exp and sub. If verifying, enter the secret or public key per UI instructions and confirm signature validity before trusting contents.
Tips and best practices
Treat decoded JWTs as sensitive—they often contain emails and roles.
Rotate secrets if you accidentally expose tokens in tickets or chats.
Learn more: Base64, Hashes, JWTs, and Developer Encoding Tools
JWT Decoder FAQ
Answers to common questions about JWT Decoder.
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