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JWT Decoder

Decode JSON Web Tokens. View JWT header and payload without verification.

How to Use JWT Decoder

1

Paste your JWT token

Copy the JWT from your API response, browser storage, or authentication header and paste it into the decoder input field.

2

View decoded header

The header section is decoded instantly showing the signing algorithm (alg), token type (typ), and key ID (kid) if present.

3

Inspect payload claims

Review all payload claims including issuer, subject, audience, expiration, and any custom claims. Expired tokens are clearly flagged.

4

Copy decoded data

Use the copy buttons to grab the decoded header or payload JSON for debugging, documentation, or sharing with your development team.

About JWT Decoder

JWT decoder online — decode and inspect JSON Web Tokens to reveal header, payload, and signature components instantly. This free JWT parsing tool displays all token claims including issuer, audience, expiration time, and custom data with syntax-highlighted JSON. Essential for debugging OAuth flows, API authentication, SSO integrations, and understanding token contents. All decoding happens in your browser so your tokens stay private and secure.

Key Features

  • Decode JWT tokens instantly to inspect header, payload, and signature
  • View all token claims including issuer, audience, expiration, and custom data
  • Validate token expiration and check if the JWT is still active
  • Syntax-highlighted JSON output with collapsible sections for readability
  • Detect common JWT issues like expired tokens and malformed Base64
  • One-click copy of decoded header or payload JSON for debugging

Frequently Asked Questions

How to decode a JWT token online for free?▾
Paste your JWT into the input field and the tool instantly decodes the header and payload, displaying all claims as formatted JSON. No signup or software installation required.
How to check if a JWT token has expired?▾
The decoder reads the exp (expiration) claim and compares it to the current time, showing whether the token is still valid or has expired. The iat (issued at) and nbf (not before) claims are also displayed.
How to view JWT payload claims?▾
Paste the token and the payload section is decoded from Base64 to readable JSON. All standard claims (iss, sub, aud, exp, iat) and custom claims are displayed with syntax highlighting.
How to debug JWT authentication issues?▾
Decode both the working and failing tokens to compare their claims. Check expiration times, audience values, issuer strings, and scopes to identify authentication mismatches.
How to decode a JWT without the signing key?▾
JWT header and payload are Base64-encoded (not encrypted), so they can be decoded without the key. Only signature verification requires the signing key. This tool decodes the readable parts safely.
How to identify the JWT signing algorithm?▾
The header section contains the alg claim showing the algorithm used (e.g., HS256, RS256, ES256). The decoder displays this along with the token type (typ) claim.
How to safely decode sensitive JWT tokens?▾
All decoding happens entirely in your browser with no server communication. Your token never leaves your device, making it safe for tokens containing sensitive user data or API credentials.
How to decode JWT tokens from OAuth and SSO systems?▾
Paste the access token or ID token from any OAuth 2.0 or OpenID Connect system. The decoder shows all claims including user identity, permissions, and token metadata.