JWT Decoder: Decode & Inspect JWT Tokens Online | Free Tool
22 usesJWT Decoder Tips
Decode JWT Tokens Instantly
Paste any JWT token to see the decoded header (algorithm, type) and payload (claims, expiration) in formatted JSON.
Check Token Expiration
Automatically detects and displays the token's issued-at and expiration timestamps with validity status.
Inspect All Claims
View all standard claims (sub, iss, aud, exp, iat) and custom claims in a clean, readable format.
Client-Side Only
JWT decoding happens entirely in your browser. Your tokens are never sent to any server.
Frequently Asked Questions
How do I decode a JWT token?
Paste your JWT token into the input area. The header, payload, and signature are decoded and displayed instantly.
Can this tool verify JWT signatures?
This tool decodes JWTs but does not verify signatures, as that requires the secret key or public key which should remain secure.
What is a JWT token?
JSON Web Token (JWT) is a compact, URL-safe token format used for authentication and information exchange between parties.
Is it safe to paste my JWT here?
Yes, all processing happens in your browser. No data is transmitted. However, avoid sharing JWTs publicly as they contain sensitive claims.
How can I quickly check the expiration status of a JWT token online?
Our free JWT Decoder & Inspector allows you to instantly check the expiration status of any JWT token. After pasting your token, the tool automatically parses the 'exp' claim in the payload and displays whether the token is valid, expired, or not yet active. This helps developers and QA testers quickly diagnose token-related authentication issues without manual calculation or complex setups.
How can I quickly inspect specific JWT claims such as 'issuer' (iss) or 'audience' (aud) in my token?
Our free JWT Decoder & Inspector allows you to easily examine all claims within your JWT's payload. After pasting your token, navigate to the 'Payload' section. Here, you'll find a structured view of all key-value pairs, including standard claims like 'iss' (issuer), 'aud' (audience), 'sub' (subject), and custom claims. This instant visualization helps developers and QA engineers quickly verify expected values and troubleshoot token-related authorization issues without manual parsing.
What's the difference between decoding and verifying a JWT signature?
Decoding a JWT signature just means the tool breaks down the encoded string into its component parts: header, payload, and the signature itself. It's like opening a sealed envelope to see what's inside. Verifying the signature, however, is about checking if the token was genuinely issued by the expected party. Our tool decodes, but doesn't verify, because signature verification needs the secret or public key, which you shouldn't expose.
Is the JWT still valid if I change the payload after decoding?
Changing the payload after decoding breaks the signature. The signature is a cryptographic hash of the encoded header and payload combined with a secret key. If you modify even one character in the payload, the signature won't match. That's the whole point of JWTs — tamper detection. Think of it like a sealed envelope with a wax stamp. Our tool shows you what's inside, but altering it invalidates the token entirely.
How to Use the JWT Decoder
- Paste your JWT token into the input area
- The header, payload, and signature are decoded automatically
- Check the metadata section for expiration and claims
- Copy individual sections as needed