How to use: JWT Generator

Description

Sign and verify JSON Web Tokens entirely in your browser — HS256, HS384, HS512, RS256 and ES256 run on your own WebCrypto, fresh RSA-2048/EC P-256 pairs export as PKCS#8 and SPKI PEM, exp/iat come back as human dates, and the unsigned "none" algorithm is refused by design. Nothing is uploaded.

• Security Tools
• Because everything is computed client-side, JWT Generator is safe to use with sensitive data such as API keys, tokens or private logs.

How to use

Using JWT Generator takes three steps:

1. Paste your data into the input box (or load the example).
2. Configure the options to match your target format or scenario.
3. Copy, download or inspect the output — it updates live as you type.

Run

Examples

Builds a signed HS256 token whose exp (2030-01-01 UTC) is shown with its human UTC/local time. Secrets never leave the browser and the unsigned "none" algorithm is refused by design — for inspecting foreign tokens use the Decoder / Verifier pages (the loopback pair of this generator).

Output (generated live by the tool just now)

Signed with HS256 — the token below is the compact serialization:

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiIyNjE3MyIsInN1YiI6ImRlbW8iLCJleHAiOjE4OTM0NTYwMDB9.-ZCXzFd37b5ZNaDyjyUHfPXEyKzs9ta4TTj5AyO5xpE

Header:  {"alg":"HS256","typ":"JWT"}
Payload: {"iss":"26173","sub":"demo","exp":1893456000}

Claim times (your browser clock):
  Expires at: 1893456000 = 2030-01-01T00:00:00.000Z UTC | local: Tue Jan 01 2030 00:00:00 GMT+0000 (Coordinated Universal Time)  -> still valid

Paste the token into the Verify mode on this same page (or the JWT Verifier page) to check it; to inspect claims without verifying use the JWT Decoder page. Everything ran in your browser — the secret and key never left this machine.

This output was produced by actually running the tool, not written by hand.

Use cases

Common situations where JWT Generator helps:

• Sign and verify JSON Web Tokens entirely in your browser — HS256, HS384, HS512, RS256 and ES256 run on your own WebCrypto, fresh RSA-2048/EC P-256 pairs export as PKCS#8 and SPKI PEM, exp/iat come back as human dates, and the unsigned "none" algorithm is refused by design. Nothing is uploaded.

Parameters

This tool has no options — it works on the input alone.

FAQ

Good to know

• Everything runs client-side, so extremely large inputs are limited by your browser tab’s memory rather than by a server upload limit.

Related tools

JWT Generator → · Security Tools →