Developer tools that never leave your browser.
Twelve small tools for the cases that come up every day — JSON, YAML, Markdown, regular expressions, hashing, JWTs, cron schedules and more. Every parse and every calculation happens on your device: no upload, no log, no waiting.
Why it's worth using
Your data stays put
Anything you paste into a tool is handled in the memory of the current page and is gone when you close the tab. That is a different order of magnitude from handing your API keys, logs or configuration files to somebody else’s server.
No account, no quota
Nothing to sign up for, no usage limits, no advertising. Open it, use it, close it.
Works offline
Once a page has loaded, every tool keeps working with the network switched off — they never needed it in the first place.
Keyboard friendly
Press / to jump to search. Every tool page is fully operable from the keyboard.