JWT Encoder & Generator
Create JWT tokens with custom header, payload, and optional secret key.
About JWT Encoder & Generator
Our free JWT encoder and generator is a powerful online tool designed for developers, API engineers, and authentication specialists. This comprehensive JSON Web Token creator helps you create JWT tokens with custom headers, payloads, and secret keys instantly in your browser. With complete privacy and no data sent to any server, you can confidently generate tokens for testing, development, and learning JWT implementation without any security concerns.
Key Features
- ✓ Custom JWT Creation: Generate JWT tokens with completely customizable header and payload JSON
- ✓ Algorithm Selection: Choose from multiple signing algorithms (HS256, HS384, HS512, RS256, ES256, etc.)
- ✓ Secret Key Support: Use custom secret keys for token signing with secure input handling
- ✓ Claim Builder: Easily add standard JWT claims (sub, iat, exp, aud, iss, etc.)
- ✓ Real-Time Generation: Instantly generate tokens as you modify header and payload
- ✓ Token Validation: Verify generated tokens are properly formatted before use
- ✓ Copy & Download: Easily copy tokens or download for use in your applications
How to Use the JWT Encoder
- Configure Header: Enter your JWT header with algorithm type (e.g., {"alg":"HS256","typ":"JWT"})
- Create Payload: Add your JWT payload with claims containing user data and metadata
- Enter Secret: Optionally enter your secret key for token signing (for HMAC algorithms)
- Generate Token: Click "Encode" to generate your JWT token
- Copy or Download: Copy the token to clipboard or download it for use in your application
Understanding JWT Encoding
JWT encoding takes your header and payload information and combines them with a signature to create a secure token. The process involves three steps of Base64URL encoding and signing:
Step 1: Base64URL Encode Header
The header JSON object is converted to a string and Base64URL encoded
{"alg":"HS256","typ":"JWT"} → eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9
Step 2: Base64URL Encode Payload
The payload JSON object is converted to a string and Base64URL encoded
{"sub":"123","name":"John"} → eyJzdWIiOiIxMjMiLCJuYW1lIjoiSm9obiJ9
Step 3: Create Signature
Sign the combined header and payload with your secret key using the specified algorithm
HMACSHA256(header.payload, secret) → dozjgNryP4J3jVmNHl0w5N_XgL0n3I9PlFUP0THsR8U
Final Token
Combine all three parts with dots to create the complete JWT
header.payload.signature
Common JWT Claims for Payloads
Authentication Claims
sub- Subject (user ID)iss- Issuer (who created token)aud- Audience (intended for whom)iat- Issued at (Unix timestamp)exp- Expiration (Unix timestamp)nbf- Not before (Unix timestamp)
User Information Claims
email- User's email addressname- User's full nameroles- User roles/permissionsscope- OAuth 2.0 scopejti- JWT ID (unique identifier)
Common Use Cases
🧪 Testing & Development
Create test tokens for development and debugging authentication features
🔐 API Authentication
Generate tokens for API endpoint testing and authorization verification
🪐 OAuth 2.0 Implementation
Create ID tokens and access tokens for OAuth 2.0 and OpenID Connect flows
📱 Mobile App Integration
Generate tokens for testing mobile application authentication systems
📚 Learning & Training
Understand JWT structure and creation by building custom tokens from scratch
🔧 Integration Testing
Create tokens for testing integration between systems that use JWT authentication
Why Choose Our JWT Encoder?
JWT Encoding Best Practices
JWT Payload Examples
Basic User Auth
{
"sub": "user123",
"name": "John Doe",
"email": "john@example.com",
"iat": 1516239022,
"exp": 1516242622
}
OAuth 2.0 Token
{
"iss": "https://auth.example.com",
"aud": "api.example.com",
"sub": "user456",
"scope": "read write",
"iat": 1516239022,
"exp": 1516242622
}
Frequently Asked Questions
Is my token data safe when using this encoder?
Yes, completely safe. All token generation happens locally in your browser. Your headers, payloads, and secret keys are never transmitted to any server.
Can I use these tokens in production?
Yes, tokens generated here are valid JWTs. However, for production use, implement proper token generation on your secure backend server rather than in the browser.
What's the difference between HS256 and RS256?
HS256 (HMAC) uses a shared secret for both signing and verification. RS256 (RSA) uses a private key for signing and public key for verification, suitable for distributed systems.
How should I set the "exp" claim?
The "exp" claim should contain a Unix timestamp (seconds since January 1, 1970) indicating when the token expires. For a 1-hour expiration, add 3600 to the current timestamp.
Can I add custom claims to the payload?
Yes! You can add any custom claims you want to the payload JSON. They'll be included in the generated token.
What if I don't provide a secret key?
For HMAC algorithms (HS256, HS384, HS512), the secret is required. For asymmetric algorithms (RS256, ES256), you don't need a secret in this tool, but server-side implementation requires proper key management.
JWT Tools Workflow
Typical JWT development workflow combines our encoder and decoder tools:
Start Creating JWT Tokens Today
Whether you're a backend developer implementing authentication, an API engineer testing token validation, a security professional learning JWT implementation, or a DevOps engineer managing token generation, our JWT encoder and generator is the perfect tool. Create and test tokens instantly with complete privacy—no signup required!