JWT Token Builder & Signer
Build and sign custom JSON Web Tokens (JWT) in your browser. Configure claims, expiration (exp), audience (aud), and sign with HS256 or RS256.
1 How to Use JWT Token Builder & Signer
- 1. Edit your payload JSON.
- 2. Provide a signing key.
- 3. Copy the generated three-part signed JWT string.
⚙️ Cryptographic Specifications
- Algorithm
- RFC 7519 Sign
- Execution Engine
- Web Cryptography API (SubtleCrypto)
- Environment
- Client Browser Sandbox
- Network Telemetry
- 0 Bytes (Zero Server Transmission)
🛡️ Security & Compliance
Enterprise developers can safely execute this tool with production secrets. Because execution takes place entirely within your browser's local V8 JavaScript runtime, no payloads are transmitted over HTTP, cached on third-party proxies, or stored in server logs.
Verified Safe for SOC2, HIPAA, and GDPR developer compliance audits.
Frequently Asked Questions
How is the signature calculated?
Base64URL(Header) + "." + Base64URL(Payload) hashed with your secret key using HMAC-SHA256.
Related Cryptographic Tools
JWT Token Decoder
Decode and inspect JSON Web Tokens (JWT) client-side. Parse header, payload claims (iss, sub, exp, iat), and signature without sending tokens to any server.
JWT Signature Verifier
Verify HMAC (HS256, HS384, HS512) or RSA/ECDSA signatures of JWT tokens client-side using Web Crypto API. Confirm payload integrity locally.