JWT Decoder
Decode and verify JWT tokens
This free online jwt decoder runs in your browser and is part of our Developer Tools collection.
JWT Decoder
Decode and inspect JSON Web Tokens (JWT). View header, payload, and signature.
About JWT:
- JWT consists of three parts: Header, Payload, and Signature
- Header contains token type and signing algorithm
- Payload contains claims (user data, expiration, etc.)
- Signature is used to verify the token's authenticity
- Common claims: iss (issuer), sub (subject), exp (expiration), iat (issued at)
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Instant In-Browser Execution
Runs locally in JavaScript without wait times or server delays.
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100% Privacy & Security
Your inputs and files are never stored or logged on remote servers.
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Cross-Device Responsive
Fully optimized for mobile smartphones, tablets, and desktop displays.
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100% Free Forever
No subscription fees, no signups, and no software installations.
How to Use the Online JWT Decoder
1
Paste Encoded JWT Token
Paste your `eyJhbGciOi...` JSON Web Token into the input area.
2
Inspect Header Claims
Examine the token header: signing algorithm (`alg`, e.g. HS256 or RS256) and token type (`typ`).
3
Analyze Payload Claims & Expiry
Review token subject (`sub`), issuer (`iss`), audience (`aud`), and check live expiration countdown (`exp`).
4
Verify Signature Note
Inspect the signature block verification status without exposing private secrets.
Frequently Asked Questions
Common questions about using this free online jwt decoder.
Is it safe to paste private JWT tokens into this decoder? ▾
Yes! The decoding is executed 100% locally in your web browser by splitting the three dot-separated Base64Url segments. Your tokens are never transmitted to any server or recorded in logs.
How does the expiration check work? ▾
The decoder reads the `exp` claim (Unix timestamp in seconds) and compares it with your computer's current UTC clock, displaying a badge showing whether the token is currently Active or Expired.
Why does a JWT contain three distinct sections separated by dots? ▾
A JWT consists of Header (algorithm & token type), Payload (user identity and permission claims), and Signature (cryptographic hash validating that the header and payload have not been forged).
Can a user modify their permissions inside a JWT token? ▾
No. If a user modifies their payload claims (e.g. changing `"role": "user"` to `"admin"`), the backend signature verification will fail because only the authentication server possesses the private secret key required to sign the token.
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