About JWT Builder
Create and sign JSON Web Tokens (JWT) directly in your browser. Build tokens with custom claims, set expiration times, and sign with HMAC algorithms (HS256, HS384, HS512). Perfect companion to the JWT Decoder for full JWT workflow.
How to Use
- 1Select signing algorithm (HS256 recommended)
- 2Enter your secret key
- 3Edit the payload JSON with your claims
- 4Use quick buttons to add standard claims
- 5Set expiration time with preset buttons
- 6Copy the generated token
Key Features
- HMAC algorithms (HS256, HS384, HS512)
- Custom payload editor with JSON validation
- Quick add standard claims (iss, sub, exp, iat, etc.)
- Preset expiration times (15m, 1h, 24h, 7d, 30d)
- Color-coded token display
- Real-time token generation
- Client-side signing for security
Common Use Cases
Frequently Asked Questions
Is it safe to create JWTs in the browser?
Yes, all signing happens client-side. Your secret key never leaves your browser. However, for production, use server-side signing.
Why only HMAC algorithms?
HMAC (symmetric) algorithms can be implemented with WebCrypto. Asymmetric algorithms (RS256) require private key handling which is more complex.
Privacy First
All processing happens directly in your browser. Your files never leave your device and are never uploaded to any server.
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