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    JWT DecoderFree Online Developer Tool

    JWT Decoder is a free online developer tool. Decode and inspect JSON Web Tokens to view their header, payload, and signature.

    JWT Token
    100% Private100% Private
    InstantInstant
    Any DeviceAny Device
    Free ForeverFree Forever
    How to useHow to use & Tips

    Steps

    1. 1Paste your JWT token into the input field (the full token including all 3 parts)
    2. 2Click 'Decode JWT' to parse the token
    3. 3View the decoded Header (algorithm and token type) and Payload (claims)
    4. 4The Signature is shown separately — note it cannot be verified without the secret key
    5. 5Use Clear to reset and decode a new token

    Use Cases

    • -Debug authentication issues by inspecting JWT claims and expiration times
    • -Verify the algorithm and token type in the JWT header during API development
    • -Inspect user roles, permissions, and custom claims in access tokens
    • -Check token expiration (exp claim) to diagnose session timeout issues
    • -Understand the structure of JWTs from third-party identity providers (Auth0, Cognito, etc.)

    About JWT Decoder

    Everything you need to know about this tool and how to get the most out of it.

    What is JWT Decoder?

    What is JWT Decoder?

    A JWT Decoder is a tool that parses and displays the contents of a JSON Web Token (JWT). JWTs are widely used in modern web authentication — they encode user identity, permissions, and session information in a compact, URL-safe format. Decoding a JWT reveals its header (algorithm and token type) and payload (claims like user ID, email, roles, and expiration time).
    How JWT Decoder Works

    How JWT Decoder Works

    A JWT has three parts separated by dots: Header.Payload.Signature. Each part is Base64URL-encoded. This tool decodes the first two parts (header and payload) from Base64URL and parses them as JSON, displaying them in a readable, formatted view. The signature part is shown as-is since verifying it requires the secret or public key.
    Why Use JWT Decoder?

    Why Use JWT Decoder?

    JWT decoding is essential for debugging authentication flows, understanding token contents, and diagnosing issues like expired tokens, missing claims, or incorrect permissions. Instead of manually decoding Base64 and parsing JSON, this tool gives you an instant, formatted view of any JWT's contents.
    Tips

    Tips & Best Practices

    • 1Check the 'exp' claim to see when a token expires — it's a Unix timestamp (seconds since epoch)
    • 2The 'iat' claim shows when the token was issued, 'nbf' shows when it becomes valid
    • 3Never use JWT decoding to 'verify' a token — only the server with the secret key can do that
    • 4If you see 'alg: none' in the header, that's a security red flag — the token has no signature

    Frequently Asked Questions