package.README.md Maven / Gradle / Ivy
**IMPORTANT:** This library doesn't validate the token, any well-formed JWT can be decoded. You should validate the token in your server-side logic by using something like [express-jwt](https://github.com/auth0/express-jwt), [koa-jwt](https://github.com/stiang/koa-jwt), [Microsoft.AspNetCore.Authentication.JwtBearer](https://www.nuget.org/packages/Microsoft.AspNetCore.Authentication.JwtBearer), etc.
[](https://opensource.org/licenses/MIT)
[](https://circleci.com/gh/auth0/jwt-decode)
:books: [Documentation](#documentation) - :rocket: [Getting Started](#getting-started) - :speech_balloon: [Feedback](#feedback)
## Documentation
- [Docs site](https://www.auth0.com/docs) - explore our docs site and learn more about Auth0.
## Getting started
### Installation
Install with NPM or Yarn.
Run `npm install jwt-decode` or `yarn add jwt-decode` to install the library.
### Usage
```js
import { jwtDecode } from "jwt-decode";
const token = "eyJ0eXAiO.../// jwt token";
const decoded = jwtDecode(token);
console.log(decoded);
/* prints:
* {
* foo: "bar",
* exp: 1393286893,
* iat: 1393268893
* }
*/
// decode header by passing in options (useful for when you need `kid` to verify a JWT):
const decodedHeader = jwtDecode(token, { header: true });
console.log(decodedHeader);
/* prints:
* {
* typ: "JWT",
* alg: "HS256"
* }
*/
```
**Note:** A falsy or malformed token will throw an `InvalidTokenError` error; see below for more information on specific errors.
## Errors
This library works with valid JSON web tokens. The basic format of these token is
```
[part1].[part2].[part3]
```
All parts are supposed to be valid base64 (url) encoded json.
Depending on the `{ header: