JWT Secret Key Generator & Decoder
Instant Offline Cryptographic Toolbox for Chrome
Why developers use it
Engineered for developer productivity with absolute client-side cryptographic privacy.
Offline by design
Every tool runs inside your browser. There are no servers involved.
Zero tracking
No analytics, no advertising and no telemetry of any kind.
Fast and focused
Decode a token or generate a key in one click, without leaving the page you are working on.
Minimal permissions
Built on Manifest V3 with only 2 declared permissions and zero persistent background overhead.
Tools included
Five essential cryptographic utilities available directly in your popup window.
JWT Decoder
Inspect the header, payload and time claims (exp, nbf, iat) with active, expired and not-yet-valid status. Decoding is not verification: it never checks the signature. Accepts a pasted "Bearer ..." token.
JWT Secret Generator
128 to 512-bit secrets in hex, Base64 or Base64URL, generated with the Web Crypto API for HS256, HS384, and HS512.
UUID v4 Generator
Up to 20 RFC 4122 v4 UUIDs at once, with or without hyphens, lowercase or uppercase.
Base64 and Base64URL
Encode and decode text with full UTF-8 support for multilingual characters, Arabic, and emoji.
Hash Generator
SHA-256, SHA-384, SHA-512 and SHA-1 computed locally in browser memory (SHA-1 is flagged as deprecated).
How it works
Instant cryptographic actions in three simple steps.
Open from your toolbar
Click the extension icon in Chrome or use a custom shortcut to trigger the instant popup window.
Generate or inspect
Select your cryptographic tool, adjust bit length or encoding, or paste your token into the inspector.
Copy directly to code
One-click copy the output into your .env file, shell terminal, API test client, or application backend.
Right-click shortcuts
Select text on any web page, then use the browser's right-click menu: Decode as JWT, SHA-256 of selection, or Base64 decode selection. The selected text stays on your device.
Tip: tokens copied from an Authorization header work too; a leading Bearer prefix is removed automatically.
Privacy by design
Strict zero-leakage architecture with total cryptographic transparency.
| Permission | Why it is needed |
|---|---|
| contextMenus | Adds the right-click shortcuts when you select text. |
| storage | Remembers your last used tab and theme on your device, and hands the selected text from the right-click menu to the extension window. That text is deleted as soon as it is read. |
Frequently asked questions
Everything you need to know about the extension architecture and security guarantees.
Is it free?
Yes, the extension is free.
Does it send my tokens or keys anywhere?
No. It makes no network requests at all.
Does it verify JWT signatures?
No. It decodes tokens so you can inspect them. Verifying a signature requires your secret or public key, which should be checked on your own server.
Does it work offline?
Yes. All tools run locally in your browser.
Which browsers are supported?
It is built for Google Chrome (Manifest V3). Other Chromium-based browsers may work but have not been tested.
How do I report a problem or suggest a tool?
Use the contact page.
Ready for faster, private cryptography?
Keep high-entropy key generation and token inspection one click away in your Chrome toolbar.