DevTools360

DevTools360 JWT Decoder lets you inspect JSON Web Tokens fast. Paste any token to view header and payload claims, verify signatures, and validate time-based claims like exp, iat, and nbf. Everything runs locally for maximum privacy.

This page is the canonical JWT decoder for DevTools360 and is updated regularly to align with current JWT standards and best practices.

1. Paste the token: Add your JWT to the input editor.
2. Review claims: Inspect header and payload values in readable JSON.
3. Select algorithm: Choose the signing algorithm used by the token.
4. Verify signature: Provide a secret or public key to validate.
5. Check timestamps: Confirm exp, iat, and nbf values.

Decoded header:

{
                  "alg": "HS256",
                  "typ": "JWT"
                }

Decoded payload:

{
                  "sub": "user_123",
                  "role": "admin",
                  "iat": 1736901000,
                  "exp": 1736904600
                }

• Signature verification: Check HMAC, RSA, or ECDSA signatures locally.
• Claim validation: Confirm exp, iat, and nbf timestamps.
• Algorithm support: HS256, RS256, and ES256 families.

• Wrong algorithm: Ensure the selected algorithm matches the token header.
• Invalid signature: Check the secret or public key format.
• Expired token: Verify exp with the timestamp converter.
• Base64url issues: JWT uses URL-safe base64 without padding.

• API authentication: Validate access tokens for user sessions.
• Microservices: Share claims between services without a database call.
• Debugging: Inspect token issues in staging or production.

• Base64 encoder/decoder for inspecting token parts.
• Unix timestamp converter to validate exp and iat values.
• JSON viewer to inspect decoded payloads.
• Regex tester for claim pattern validation.

All JWT decoding and verification happens locally in your browser. Tokens and keys never leave your device, and the tool works even without an internet connection.

• RFC 7519 - JSON Web Token (JWT)
• RFC 7515 - JSON Web Signature (JWS)

Maintained by the DevTools360 team. Last updated: 2026-01-15. We focus on private, client-side JWT inspection and verification.