JWT Debugger
Local only

Private browser-based JWT inspection

JWT Debugger

Decode, inspect, verify, and create JSON Web Tokens without sending your token or secret anywhere.

Input

Encoded Token

Presets:
Waiting for token Signature not checked

Decoded

Header

{}

Decoded

Payload

{}

Claims

Timeline

Security Audit

Token Health & Vulnerability Scanner

0 Critical 1 Warning Score 100/100

Verify

Secret or Public Key

Verification supports HS, RS, PS, and ES algorithms in the browser. EdDSA tokens can be decoded here, but are not verified by Web Crypto in this static build.

Developer Suite

Complete Token & Authentication Toolset

Everything you need to inspect, compare, generate, and verify auth tokens in your browser.

Educational Content

Master JWTs, OAuth 2.0 & Modern Token Security

In-depth guides, protocol comparisons, and security cheat sheets crafted to complement your development workflow.

Browse All Guides →

Architecture

JWT vs Session

Stateless vs stateful authentication, database hits, scaling, and token revocation tradeoffs.

Protocols

OAuth vs JWT

Authorization framework vs token format. How they pair in modern API security.

Security

Refresh Token Explained

Single-use rotation (RTR), automatic reuse detection, and safe cookie storage patterns.

Cryptography

RS256 vs HS256

Asymmetric RSA public/private keys vs symmetric HMAC shared secrets in microservices.

Security

JWT Attack Examples

Real-world exploit walkthroughs: alg none bypass, key confusion, brute force, and defenses.

Best Practices

JWT Best Practices

10 essential production rules: algorithm whitelisting, cookies, expiry, and validation.

Debugging

Common JWT Errors

How to fix invalid signature, TokenExpiredError, malformed tokens, and clock drift.

Reference

JWT Cheat Sheet

Quick reference for registered claims, JOSE headers, algorithms, and CLI commands.

Specification

RFC 7519 Guide

A plain English guide to the official IETF standard, JOSE suite, and claim registries.

What It Checks

Readable claims, signature status, and token timing

Decode

Header and payload are parsed locally with helpful formatting and JSON validation.

Verify

Decode, verify, and generate JSON Web Tokens, which are an open, industry standard RFC 7519 method for representing claims securely between two parties.

Generate

Create signed tokens for testing flows, demos, and local development.

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