JSON Web Token (JWT) Builder & Signer
Build, configure, and digitally sign custom JSON Web Tokens (JWT) for authentication testing.
Test Authentication Middleware with Custom Tokens
During auth development, you often need valid JSON Web Tokens (JWT) with specific scopes, expiration dates, or secret keys to test middleware configurations. Our JWT builder and signer enables you to generate these tokens instantly.
Algorithmic Verification
Configure header metadata, choose signing algorithms (HMAC SHA-256), specify payload data, and input your signing secret key. The utility will output the encoded token ready to be used in client requests.
Key Benefits & Features
Interactive Payload Editor
Easily edit token claims in standard JSON formatting.
Flexible Secrets
Sign tokens with custom secret keys to match local developer settings.
Color-Coded Segments
Breaks down the generated string into header, payload, and signature blocks.
How to Use the JWT Builder & Signer Step-by-Step
This utility runs entirely inside your browser using client-side JavaScript. We prioritize your security: none of your inputted text is logged or stored.
- 1
Input or edit the JSON header (e.g. HS256 algorithm).
- 2
Configure the JSON payload with custom claims, scopes, or expirations.
- 3
Enter the secret key used to sign the token.
- 4
Click "Sign Token" to generate the final encoded JWT string.
Practical Examples
Payload: {"sub": "user123"}, Secret: my-secret-key
Frequently Asked Questions (FAQ)
Is my secret key secure?▼
Yes, all token encoding and signing happens completely inside your browser using client-side JavaScript. No keys or payloads are sent to any server.
What signing algorithms are supported?▼
The client signer supports the HMAC SHA-256 (HS256) algorithm, which is standard for web application tokens.
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