JWT Decoder Online

Instantly decode and inspect any JSON Web Token. View the header, payload, claims, and expiry. Free, client-side, no data sent anywhere.

What is a JWT?

A JSON Web Token (JWT) is a compact, URL-safe way to represent claims between two parties. It consists of three Base64URL-encoded parts separated by dots: header.payload.signature.

JWT Structure

Header — algorithm and token type (e.g., {"alg":"HS256","typ":"JWT"}).

Payload — claims such as sub (subject), iat (issued at), exp (expiration), and custom data.

Signature — HMAC or RSA signature to verify authenticity. This tool does not verify signatures — it only decodes.

API Example

## Decode JWT with curl
curl -X POST https://apitoolkit.pro/api/v1/jwt-decode \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."}'

## JavaScript
const res = await fetch('https://apitoolkit.pro/api/v1/jwt-decode', {
  method: 'POST',
  headers: { 'X-Api-Key': 'YOUR_API_KEY', 'Content-Type': 'application/json' },
  body: JSON.stringify({ token: 'eyJhbGciOi...' })
});
const { header, payload, signature } = await res.json();

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