JWT Decoder

JWT Decoder | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Security
Input types: text, checkbox
Output type: text
Sample coverage: 4
API ready: Yes

Overview

The JWT Decoder is a secure, browser-based utility that allows you to instantly inspect the contents of JSON Web Tokens. By pasting your encoded string, you can view the header, payload, and signature components in a readable format without sending data to a server.

When to use

Debugging authentication issues in web applications.
Verifying the claims and expiration time within a token.
Inspecting token structure during API development.

How it works

1Paste your encoded JWT string into the input field.
2Select your display preferences to show or hide the header, payload, or signature.
3The tool automatically decodes the Base64Url-encoded segments and displays the JSON structure.

Use cases

Checking user roles and permissions embedded in the token payload.
Troubleshooting 'Invalid Token' errors by inspecting the 'exp' (expiration) claim.
Reviewing custom claims added by your authentication provider.

Examples

1. Debugging Expired Sessions

Frontend Developer

Background

A user is being logged out prematurely from a web application.

Problem

The developer needs to check the 'exp' (expiration) claim inside the JWT to see if the token is expiring earlier than expected.

How to use

Paste the JWT from the browser's local storage into the decoder and check the 'Show Payload' option.

Outcome

The developer identifies that the 'exp' timestamp is set to a past date, confirming the issue lies with the token generation logic.

2. Verifying User Claims

Backend Engineer

Background

An API is failing to authorize a user despite them being logged in.

Problem

The engineer needs to verify if the 'roles' or 'permissions' array is correctly included in the token payload.

How to use

Input the token into the decoder and inspect the JSON payload section.

Outcome

The engineer discovers the 'roles' field is missing from the payload, indicating a configuration error in the authentication service.

FAQ

Is my token data sent to a server?

No, all decoding happens locally in your browser. Your data never leaves your device.

Can this tool verify if a token is valid?

This tool decodes the content for inspection but does not perform cryptographic signature verification.

What parts of the JWT can I view?

You can view the header, the payload (claims), and the signature, depending on your selected display settings.

Does this work with expired tokens?

Yes, the decoder will display the contents of any validly formatted JWT, regardless of its expiration status.

Is the signature decoded or verified?

The signature is displayed as a raw string; this tool does not validate the signature against a secret key.

Run this tool

Inputs

Result

Examples that match this tool

Continue with connected tools and hubs

Inputs

Result

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Debugging Expired Sessions

2. Verifying User Claims

FAQ

JWT Samples

Terraform Plan JSON Samples

Hex/Unicode Encoding Format Samples

WebRTC Real-Time Communication Samples

JWT Inspector & Verifier

Distributed Trace Decoder & Waterfall Visualizer

BSON Converter

Smile Converter

Authentication, Password, and Token Security Tools

Key Generation, Signatures, and Trust Verification Tools

Token, Session, and 2FA Workflow Tools

JSON Interchange and Format Translation Tools