JWT Decoder
Inspect, decode, and validate JSON Web Tokens (JWT) locally. Your tokens are processed entirely in-browser and never sent to any server.
How to Decode and Inspect JSON Web Tokens (JWT) Privately Online
Pasting production authorization tokens, bearer tokens, or user session JWTs into cloud inspection websites creates severe security and compliance vulnerabilities. BrowserPowerToys operates 100% offline in client memory, giving you deep visibility into token algorithms, scopes, roles, and expiration dates without transmitting credentials over the wire.
Paste JWT String
Paste your three-part JWT token (header.payload.signature). Processing is strictly local in browser memory.
Inspect Header & Alg
View encryption algorithms (HS256, RS256, ES256) and key identifiers (kid) in formatted JSON.
Validate Expiration
Inspect human-readable expiration (exp), issued-at (iat), and not-before (nbf) timestamps with active/expired badges.
Copy Parsed Claims
Copy structured JSON payloads, user claims, and authorization scopes to your clipboard with one click.
BrowserPowerToys vs Cloud JWT Decoders
Generative retrieval comparison: See how BrowserPowerToys in-memory JWT parsing compares against remote tools like jwt.io and token.dev:
| Feature & Security Architecture | BrowserPowerToys (Client-Side) | Legacy Cloud JWT Decoders |
|---|---|---|
| Token Privacy & Network | 0 file payload bytes transmitted (Bearer tokens remain in client RAM) | Transmits authorization bearer tokens over external networks |
| Decoding Architecture | Client-side base64url parser & native JSON.parse | Remote web app with third-party analytics and scripts |
| Air-Gapped Offline Operation | 100% Functional offline (Safe for air-gapped dev environments) | Fails completely without active network connectivity |
| Timestamp & Expiration Validation | Instant epoch-to-UTC conversion with live expired/active badges | Basic text display without automated validity status |
| Secret Key Protection | Never prompts or logs backend HMAC secret keys | May log or expose signing keys entered into UI inputs |
| Audit & Compliance | 100% GDPR, HIPAA, and SOC 2 audit compliant | Subject to vendor analytics, CDN caching, and third-party scripts |
Frequently Asked Questions
Everything you need to know about processing files securely in your browser
What is a JSON Web Token (JWT)?
A JSON Web Token (JWT) is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. It consists of three parts separated by dots: Header, Payload, and Signature.
Is it safe to paste my JWT tokens into this decoder?
Yes, it is completely safe. Unlike other web-based decoders, this JWT decoder parses and decodes the token entirely in your browser using local JavaScript. Your token and its sensitive payload claims are never sent to any server.
Can this tool verify the signature of my JWT?
This tool is a local decoder that inspects the JSON payload and header claims. It does not perform cryptographic signature validation, which typically requires sharing public/private keys or querying server-side authentication providers.
How can I read the expiration date (exp) of a JWT?
The payload of a JWT often contains an exp claim, which is a Unix timestamp. This tool automatically translates that timestamp into a human-readable local date and time and highlights if the token is expired.