JWT Token Generator & Signer (Local)
Locally signs a compact JWT by Base64URL-encoding its header and payload and creating an HMAC (HS256/384/512) or RSA PKCS#1 v1.5 (RS256/384/512) signature. It does not verify tokens.
About this jwt token generator & signer (local)
Locally signs a compact JWT by Base64URL-encoding its header and payload and creating an HMAC (HS256/384/512) or RSA PKCS#1 v1.5 (RS256/384/512) signature. It does not verify tokens Validates and converts interface schemas client-side without transmitting private endpoint specifications.
API contract & interface schema logic
Base64URL encodes the header and payload, then signs the joined input with HS256, HS384, HS512, RS256, RS384, or RS512. HMAC modes use a text secret (default development-secret); RSA modes require a private PKCS#8 PEM or JWK. It does not verify a token or establish issuer trust.
Worked schema conversion scenario
Scenario: An API tester generates a mock signed JWT token with custom claims for development testing.
Sample input:
Processing: Base64URL-encodes the header and payload, then signs with HMAC HS256/384/512 or RSA PKCS#1 v1.5 RS256/384/512. It does not verify the token.
Illustrative output:
Schema version & syntax constraints
A missing secret falls back to development-secret, and an absent payload gets demo claims. Never treat these defaults as production credentials; no token verification is performed.
API specifications and schema models in JWT Token Generator & Signer (Local) reflect OpenAPI and JSON Schema standards. Verify generated schemas against your runtime validator.
Client-side schema processing boundary
Schema analysis and protocol mapping in JWT Token Generator & Signer (Local) execute locally in the browser tab without uploading endpoint definitions.
OpenAPI Specification & JSON Schema standards
OpenAPI Specification standards and JSON Schema draft definitions:
JWT Token Generator & Signer (Local) verification · Audit standards
How to use it
- Paste JSON with payload, optional header and either a secret or RSA private key.
- Base64URL-encode header and payload and sign locally with supported HS or RS algorithms.
- Copy the resulting JWT for development tests.
Frequently asked questions
Which JWT algorithms can this page sign?+
It accepts a JSON header and payload, then signs HS256, HS384 or HS512 with a UTF-8 secret through Web Crypto HMAC, or RS256, RS384 or RS512 with an imported or generated RSA signing key. Other alg values raise an unsupported-algorithm error.
Can you show an input and its result?+
A fixed HS256 header, payload and secret produced exactly the compact JWT whose signature was calculated independently with Node createHmac over the base64url header and payload segments.
What are the key and claim boundaries?+
The page does not validate registered claims, expiration, issuer, audience, critical headers, key strength, secret entropy, JWK sets, key rotation or signature verification. An absent payload can receive a current-time default, so it is not deterministic.
Does a signed JWT authorize a user?+
No. It creates a local token string only. Server key selection, verification, revocation, transport, storage, clock policy and authorization decisions must be implemented separately.