Free tools

Free tools for developers

Small tools for licensing and authentication. They run in your browser: nothing you type leaves this page, and there's no account to create.

Paste a JWT to read its header and claims, check its signature, and see its dates in UTC and in your time zone. Edit the claims to sign a new token.

Generate random license keys and serial numbers in the format you choose, one or ten thousand at a time. Copy them, or export them as CSV.

Encode text to base64 or decode it back, live in both directions. Detects URL-safe base64, flags invisible characters, and shows JSON as a tree.

Drop one image to get every icon of an Electron app: ICNS for macOS, ICO for Windows, PNGs for Linux and the macOS tray, in a ZIP.

Generate a 2048, 3072 or 4096-bit RSA key pair in your browser. Get it as PEM, PKCS#1, OpenSSH or JWK, encrypt it with a passphrase, and test it.

License keys your app can check in one request

LicenseManager creates a key for every Stripe purchase, emails it to your customer, and validates it from your app, online or offline.