Free Online JWT Decoder Tool
Decode and inspect any JSON Web Token (JWT) instantly — right in your browser. View the header, payload, and signature details without sending sensitive data to any server. Supports all standard algorithms including HS256, RS256, and ES256.
{
"alg": "HS256",
"typ": "JWT"
}NSSvq38GatWjctLGFWNwH_kQdZ9mOHekl-l0PSBmGUs
This tool only decodes and displays JWT contents. It does notverify cryptographic signatures. · 100% client-side
How to Use the JWT Decoder Tool
Paste Your JWT Token
Copy and paste your full JWT token (the complete string with three dot-separated parts) into the input area.
Auto-Decode Instantly
The tool automatically parses and decodes the JWT in real-time. The header and payload are Base64-decoded and displayed as formatted JSON.
Inspect Token Details
Review the decoded header (algorithm, type), payload (claims like sub, iat, exp), and signature. Check token validity with expiration warnings.
Powerful JWT Decoder Features
Everything you need to inspect and debug JSON Web Tokens — entirely in your browser.
Instant Parsing
Paste any JWT token and see the header, payload, and signature decoded instantly. No buttons to click.
Formatted JSON
Header and payload are displayed as beautifully formatted, syntax-highlighted JSON for easy reading.
Expiration Detection
Automatically detects and warns about expired tokens by checking the exp claim against the current time.
Claim Analysis
Recognizes standard JWT claims like iss, sub, aud, exp, nbf, iat, jti and displays them with human-readable labels.
Signature Info
Shows the raw signature portion of the token and identifies the signing algorithm from the header.
Copy Any Section
Copy the decoded header, payload, or entire token details to your clipboard with a single click.
Clear & Sample
Load a sample JWT token to test the decoder or clear the input instantly.
100% Client-Side
All decoding happens in your browser. Your JWT tokens never leave your device — no server uploads, no logging, no privacy risks.
Why Use Our JWT Decoder Tool
The safest way to inspect JWT tokens online. Complete privacy, instant results, and developer-friendly features.
100% Free
No hidden fees, no premium plans, no usage limits. Decode as many JWT tokens as you need, whenever you need.
Privacy First
Your tokens never leave your browser. Unlike other JWT debuggers that send data to servers, everything is processed locally.
Instant Results
Real-time decoding as you paste. See the decoded header and payload immediately without waiting or clicking buttons.
Developer-Friendly
Perfect for debugging authentication flows, inspecting access tokens, verifying ID token claims, and understanding JWT structure.
Key Highlights
- No sign-up or registration required
- Processes everything in your browser — zero server uploads
- Formatted JSON output for header and payload
- Expiration date detection and warnings
- Recognizes and labels standard JWT claims
- Works on any device — desktop, tablet, or mobile
Frequently asked questions
What is a JWT token?
JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. It consists of three parts: a header (algorithm & token type), a payload (claims/data), and a signature (for verification). These parts are Base64-encoded and separated by dots.
Is this JWT decoder really free?
Yes, completely free. There are no hidden charges, no usage limits, and no premium features locked behind a paywall. Use it as much as you need, whenever you need it.
Is my data secure?
Absolutely. All decoding happens entirely in your browser using JavaScript. Your JWT tokens are never sent to any server, stored, or logged. This means sensitive authentication tokens, user IDs, and personal information stay completely private.
Can I verify JWT signatures?
This tool decodes and displays the header, payload, and signature portions of a JWT, but it does not verify cryptographic signatures. Signature verification requires the secret key (for HMAC) or public key (for RSA/ECDSA), which this tool never has access to — keeping your tokens safe.
What JWT algorithms are supported?
The tool can decode tokens using any standard JWT algorithm including HS256, HS384, HS512, RS256, RS384, RS512, ES256, ES384, ES512, EdDSA, and none. The algorithm is read from the header's alg field.
What does 'expired token' mean?
A JWT token contains an exp (expiration) claim that specifies when the token should no longer be accepted. Our tool compares this timestamp with the current time to warn you if a token has expired — helping you debug authentication issues.
What standard JWT claims do you detect?
We detect and label standard registered claims including: iss (Issuer), sub (Subject), aud (Audience), exp (Expiration Time), nbf (Not Before), iat (Issued At), jti (JWT ID), and custom claims are shown as-is.
Do I need to install anything?
No installation required. The JWT decoder works entirely in your web browser. Just open the page and paste your token. No downloads, no plugins, no setup.
Can I use this on my phone?
Yes, the tool is fully responsive and works on all devices — desktops, tablets, and smartphones. The interface adapts to your screen size for comfortable use anywhere.