JWT Encode

Header (Algorithm and token type)

Payload (Claims)

Quick add common claims：

Signature (Signing settings)

Signing algorithm

Symmetric secret

✅ auto generated

Key (Secret)

Systemauto generatedrandom key

Algorithm requirement: HS256 Minimum 32 bytes

Current length: 32bytes ✅

Key encoding:

✅ Key length is sufficient.

RSAkey pair

✅ auto generated

JWK format PEM format

Public key JWK (read only - extracted from the private key)

Private key+Public key JWK (Auto-generated, replaceable)

Systemauto generatedkey pair（JWK format）

✅ JWKformat is valid，contains all required fields

Public key PEM(Auto-generated, replaceable)

Private key PEM (Auto-generated, replaceable)

Systemauto generatedkey pair（PEM format）

✅ PEMformat is valid，PKCS#8standard private key

Result

Configuration Header and Payload after
Click"Generate JWT"to generate a token

GeneratedJWT

Encoding principle

Header

Base64URL↓

Payload

Base64URL↓

Signature

Signature↓

Header . Payload . Signature = JWT

Signing algorithm explained

HMAC Signing algorithm

Step 1: Base64URL Encode

header = Base64URLEncode({"alg":"HS256","typ":"JWT"}) payload = Base64URLEncode({...})

Step 2: Decode the secret (based on the secret encoding）

key_bytes = DecodeKey(secret_key, encoding)

Convert the key into bytes according to the selected key encoding

Step 3: HMAC Signature

signature = HMAC_SHA256(key_bytes, header + "." + payload)

Use the decoded key bytes to create an HMAC signature over the joined data

Step 4: Assemble JWT

jwt = header + "." + payload + "." + Base64URLEncode(signature)

Verification process with the same key

expected_sig = HMAC_SHA256(key_bytes, header + "." + payload) isValid = (expected_sig == received_signature)

Recalculate the signature with the same key and compare it

RSA Signing algorithm

Step 1: Base64URL Encode

header = Base64URLEncode({"alg":"RS256","typ":"JWT"}) payload = Base64URLEncode({...})

Step 2: Private key signing

signature = RSA_Sign(private_key, SHA256(header + "." + payload))

Hash the joined data, then sign it with the private key

Step 3: Assemble JWT

jwt = header + "." + payload + "." + Base64URLEncode(signature)

Verification process with the public key

isValid = RSA_Verify(public_key, SHA256(header + "." + payload), signature)

Anyone can verify the signature with the public key

JWT Info

Algorithm: -

Issued at: -

Not before: -

Expiration time: -

TokenLength: -

Generated at: -

⚠️

Security note

JWT encoding and signing happen locally in your browser. Protect key material carefully and avoid using JWTs in unsafe environments.

JWT Generator

JWT Generator creates JSON Web Tokens for local debugging, API experiments and documentation examples. You can edit the header and payload, provide a test secret and generate a signed token. The page is intended for development workflows where you need a quick token shape, not for storing or sharing production credentials.

Privacy note: All processing happens in your browser — your data never leaves your device.

How to use

Paste or edit the JWT header and payload, choose the signing algorithm supported by the page, enter a test secret and generate the token. Review the output before using it in a local request. Never paste production signing keys, private keys or real user credentials into any online tool.

Example: Example: create a payload with `sub`, `name`, `iat` and `exp`, sign it with a local test secret and copy the token into an API client.

FAQ

Can I use production secrets here?

No. Use only local test secrets and disposable sample data.

What is this useful for?

It is useful for API debugging, documentation examples and local integration tests.

Does the page send my token to a server?

The English build is designed to run the token workflow in the browser.

JWT Generator

How to use

FAQ

Can I use production secrets here?

What is this useful for?

Does the page send my token to a server?

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