Inspect JWT tokens from Auth0, Firebase, Supabase, and custom OAuth2 providers. Decodes algorithm, issuer, subject, expiration time (exp), and custom claims.
Specifications & Details
Feature
Specification
Execution Mode
In-Browser (Client-Side WebAssembly / JS)
Privacy Guarantee
Zero Server Transfer — 100% Local Device Processing
Supported Formats / Inputs
jwt, decode, token
Pricing & Usage Limits
100% Free Forever — No Signup, Unlimited Use
Browser Compatibility
Chrome, Firefox, Safari, Edge, Mobile Browsers
About this tool
JWT Decoder shows header and payload claims from a JSON Web Token. Inspect exp, sub, and custom claims while debugging auth — decoding is local (verification depends on options).
Common Use Cases for developer tools
When you need to inspect JWT tokens from Auth0, Firebase, Supabase, and custom OAuth2 providers, JWT Token Debugger & Claims Decoder handles it right in your browser — no download or installation required.
Use JWT Token Debugger & Claims Decoder to prepare data before sharing or archiving it: everything stays on your device.
JWT Token Debugger & Claims Decoder works on any computer, including shared or locked-down machines where you cannot install software.
Bookmark JWT Token Debugger & Claims Decoder for repeatable tasks: open the page, run the job, download the result — free and unlimited.
Key Advantages
Zero server upload. Your files are processed entirely in your browser and never reach ThothBox servers.
Instant results. No upload queues or waiting rooms: the job runs at native browser speed on your own hardware.
No registration. No account, email, or usage limits — open the page and start working immediately.
How to use
Paste the JWT string.
Inspect decoded header and payload claims.
Check expiry and audience fields when present.
Never paste production secrets into public tools you do not trust — this one runs locally.
FAQ
Is it safe to paste confidential JWT tokens here?
Yes! Unlike other online decoders, ThothBox runs 100% locally in your browser without transmitting tokens to any external server.