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How to Use

  1. 1

    Get Your JWT Token

    Copy your JWT token from your application, API response headers, browser developer tools (localStorage/sessionStorage), or authentication service.

  2. 2

    Paste or Upload Token

    Paste the token into the input field or upload a file containing the JWT token. The tool validates the format automatically.

  3. 3

    Review Decoded Components

    Examine the decoded header (algorithm, type), payload (all claims including expiration, issuer, subject, custom data), and signature.

  4. 4

    Analyze Security and Expiration

    Check the security validation section for warnings about weak algorithms, expired tokens, or sensitive data. Review expiration time and time remaining.

  5. 5

    Copy or Export Data

    Use the copy buttons to copy header, payload, or signature data for debugging. All data is formatted as readable JSON.

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How to Decode a JWT Token: Complete Guide (Without Code) 2026

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Frequently Asked Questions

How do I decode a JWT token safely?
Paste your JWT token into the input field and our tool will automatically decode the header, payload, and signature. All processing happens in your browser - no token data is sent to servers, ensuring complete privacy and security.
Can this tool verify JWT signatures?
This tool displays the signature component but does not verify it (verification requires the secret key and should be done on your server). The tool helps you inspect token contents, check expiration, and analyze structure for debugging purposes.
What JWT algorithms are supported?
Our decoder works with all JWT algorithms including HMAC (HS256, HS384, HS512), RSA (RS256, RS384, RS512), and ECDSA (ES256, ES384, ES512). The algorithm is displayed in the header analysis along with security warnings for weak algorithms.
How do I check if my JWT token is expired?
The tool automatically checks the "exp" (expiration) claim and displays whether the token is valid, expired, or about to expire. It shows the exact expiration time and time remaining in a human-readable format (days, hours, minutes).
What are custom claims in JWT tokens?
Custom claims are application-specific data in the JWT payload beyond standard claims (iss, sub, aud, exp, nbf, iat, jti). Our tool separates and displays custom claims for easy identification, helping you analyze application-specific token data.
Is it safe to decode JWT tokens online?
Yes! Our tool processes tokens entirely in your browser using client-side JavaScript. No token data is sent to our servers. JWT tokens are designed to be publicly readable - only signature verification requires the secret key, which should stay on your server.
Can I upload JWT tokens from a file?
Yes! The tool supports file upload for tokens stored in text files. Simply upload the file (up to 1MB) and the tool will extract and decode the JWT token automatically.
What information can I see in a decoded JWT?
You can see the complete header (algorithm, type, key ID), full payload (all claims including expiration, issuer, subject, audience, issued time, custom claims), signature component, token validity status, expiration status, time remaining, and security warnings.