Security & Crypto Tools
JWT Generator / Signer
Sign and decode JWTs with HS256, HS384, or HS512.
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What is JWT?
A JWT utility for development: sign tokens with a secret key and view the decoded payload of any token.
How it works
The header and payload are Base64URL-encoded and HMAC-signed with Web Crypto; decoding simply parses and Base64URL-decodes the payload segment.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Paste or type any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.
Frequently asked questions
Is this secure enough for production secrets?
Signing happens locally with Web Crypto, but for production you should still sign server-side so the secret never enters a browser at all.