JWT Signer
JSON Web Token Signing Tool
Build and sign HMAC-based JSON Web Tokens (JWT) directly in your browser.
Token format: header.payload.signature (each segment is Base64URL-encoded).
About JSON Web Tokens
A JSON Web Token (JWT) is a compact, URL-safe way to represent claims between two parties. A JWT has three parts separated by dots: a header describing the token type and signing algorithm, a payload containing the claims (such as a user ID and an issued-at time), and a signature that proves the token has not been altered. Each part is Base64URL-encoded.
This tool creates HMAC-signed JWTs (HS256, HS384, or HS512). The signature is computed over the string header.payload using your secret. Anyone with the same secret can verify the token, so keep the secret private. Note that the header and payload are only encoded, not encrypted, so never put sensitive data in a JWT payload. All signing happens locally with the Web Crypto API.
