Developer Tools
JWT Encoder
Create valid JWTs instantly. Edit header and payload as JSON, choose algorithm (HS256, HS384, HS512), enter secret, and generate a properly signed token. Live preview and validation included. All done locally in your browser.
Signing uses the Web Crypto API (HMAC). No data is sent to any server.
Creating JWTs During Development
JWTs are everywhere in modern APIs and single-page applications. Being able to quickly craft a token with specific claims (exp, sub, roles, etc.) is invaluable when testing authorization logic, mocking user sessions, or debugging why a token is being rejected.
Security Note
Only use this tool with secrets you are comfortable exposing in a browser tab. For real production tokens, always generate them on a secure backend using environment variables and proper key management. This encoder is intended for development, testing, and learning.
Frequently Asked Questions
Is it safe to use my real secret here?
Yes. Signing happens 100% in your browser using the Web Crypto API. The secret never leaves your device. For production use, always keep secrets in environment variables or secure vaults.
Which algorithms are supported?
HS256, HS384, and HS512 (HMAC + SHA). These are the most common symmetric algorithms. We do not support RSA/ECDSA public-key algorithms in this client-only tool.
Can I decode the token I just created?
Yes — the live preview shows the decoded header and payload. For full verification against the signature, use our separate JWT Decoder tool.
Related Developer Tools
- JWT Decoder (the companion tool)
- Hash Generator