BBestMint

JWT Builder & Signer

Build and HS256/HS384/HS512-sign a JWT entirely in your browser.

Edit the header and payload as JSON, supply your HMAC secret, and the tool produces a signed JWT (header.payload.signature). Signing uses Web Crypto's HMAC-SHA implementations — your secret never leaves the page.

Common use cases

  • Hand-craft a JWT for testing an authentication endpoint
  • Generate test tokens with custom claims for integration tests
  • Reproduce a tricky token bug by signing a known payload
  • Demo JWT structure (header.payload.signature) in a workshop

Frequently asked questions

Which signing algorithms are supported?▾
HMAC variants HS256, HS384 and HS512. RSA and EC signing requires importing keys and is best done with a dedicated library.
Is the secret sent over the network?▾
No — signing runs entirely in your browser via Web Crypto.
Can I round-trip with the JWT Decoder tool?▾
Yes. Sign here, then paste into the JWT Decoder to verify the structure and inspect the claims.

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