OnlineDeveloperTool
Generators & Hashes

JWT Generator Online

Build a signed HS256 JWT from your own payload and secret.

Updated

This tool runs in your browser. No account or signup is required.

Common JWT Generator tasks

Developers typically reach for this page when they need to generate a JWT for testing; create a JWT header and payload; build a test JSON Web Token. The tool is built for quick, practical work rather than a generic demo.

What matters in a jwt generator workflow

When developers compare online tools for this job, the useful capabilities tend to center on header/payload claims, signing/verification distinction, test tokens. This page keeps those practical needs in mind while linking to related tools when a different workflow is a better fit.

What is JWT Generator?

JWT Generator signs the JSON payload you provide using HMAC-SHA256 (HS256) and a secret key, and returns a token you can use for testing.

What problem does it solve?

Auth bugs often come down to what is inside a token: a wrong claim, an expired time, a missing role. Reading a JWT by hand means decoding Base64 pieces separately.

How to use JWT Generator

  1. Edit the payload JSON.
  2. Enter a secret (the default is "secret").
  3. Press Generate Token and copy the result.

Example

Input

Payload: {"sub":"1234567890","name":"John Doe"}
Secret: my-test-secret

Output

A token in the form header.payload.signature

What you can do with JWT Generator

  • Generate a JWT for testing
  • Create an HS256 token
  • Sign a JWT online

Common use cases

  • Checking claims like sub, exp and roles while debugging auth
  • Making a test token for a local API
  • Explaining to a teammate what a token carries

Related developer tasks

  • Generate a JWT for testing
  • Create an HS256 token
  • Sign a JWT online

What the JWT generator creates

  • The header is fixed: {"alg":"HS256","typ":"JWT"}.
  • The payload is the JSON you enter. It is not modified, so add iat and exp yourself if you need them.
  • The signature is HMAC-SHA256 over header.payload using the secret you type. If the secret is empty, the word secret is used.
  • Only HS256 is supported. There is no RS256 or ES256.

Use generated tokens for testing only

Tokens built here are handy for trying an API or a decoder. Do not type a production signing secret into any web page, and create real tokens on your server.

Related: JWT Decoder, SHA-256 Generator, Unix Timestamp, JSON Validator

JWT Generator FAQ

Does it verify the signature?

No. Decoding only reads the header and payload. A decoded token is not proof the token is genuine.

Is a JWT payload secret?

No. The payload is only encoded, not encrypted, so anyone holding the token can read it. Do not put sensitive data in it.

Which algorithm does the generator use?

HS256 (HMAC-SHA256) with the secret you enter.

Why does the tool say Invalid JSON payload?

The payload box must contain valid JSON. Run it through the JSON Validator to find the syntax error.

Looking for something else? Browse all developer tools.

onlinedevelopertool.com is a collection of 54 free, browser-based utilities for the small jobs that interrupt real work: formatting a JSON response, decoding a token, converting a timestamp, generating a UUID or checking a hash. Each tool has its own page with a short explanation, a worked example and answers to common questions, so you can use it and learn what it does at the same time.

There is no account to create and nothing to install. Tools run in your browser, so the text you paste is processed on your own device. The one exception is the Website Status Checker, which sends a request from your browser to the address you enter.

Three steps: paste your input, click the tool, copy the result, all inside your browser
Popular developer utilities: JWT decoder, UUID generator, Base64 decoder, SHA-256 hash, regex tester and timestamp converter

What you can do here

  • JSON Tools

    Format, validate, beautify and minify JSON, generate C#, TypeScript, Java, Python, Go, PHP and Kotlin models from it, or convert between JSON, YAML and CSV.

  • Encoders & Decoders

    URL, Base64 and HTML encoding and decoding, plus a JWT decoder for reading token claims.

  • Generators & Hashes

    Generate UUIDs and JWTs, validate UUIDs, and create MD5, SHA-256 and SHA-512 hashes.

  • Web Tools

    Timestamps, color codes, query strings and cron expressions - the small things web work keeps throwing at you.

  • Text & Data

    Format XML and YAML, count text, change case, make slugs, test regex, diff two texts and convert number bases.

  • Website Checking

    Check whether a website or URL is reachable from your browser.

Quick developer reference

  • JSON

    Keys and strings must use double quotes, and trailing commas and comments are not allowed. Those are the three most common reasons a payload fails to parse.

    Validate JSON

  • JWT

    A JSON Web Token is three Base64URL parts joined by dots: header, payload and signature. Decoding shows the claims but does not prove the token is genuine; only signature verification does.

    Decode a JWT

  • Base64

    Base64 is an encoding, not encryption. Anyone can reverse it, and it makes data roughly one third larger, so never use it to hide secrets.

    Decode Base64

  • UUID

    A version 4 UUID is made of random bits and written as 8-4-4-4-12 hexadecimal characters. Collisions are astronomically unlikely, which is why they work well as identifiers.

    Generate a UUID

  • Timestamps

    A Unix timestamp counts time since 1 January 1970 UTC. Ten digits usually means seconds and thirteen digits usually means milliseconds.

    Convert a timestamp

  • Hashes

    MD5 is fine for quick checksums but is not safe for security. Prefer SHA-256 or SHA-512, and remember that hashing is one-way and is not encryption.

    Create a SHA-256 hash

Missing a tool you need? Visit the contact page and tell us what you reach for most often. You can also browse every tool or read the About page to see how the site is built and what it does with your data.