Developer Tools
Small, repetitive tasks come up constantly in day-to-day development work — formatting a messy JSON payload, converting between JSON and CSV or XML, encoding something to Base64, testing a regular expression, checking a Unix timestamp, or converting a color between HEX, RGB, and HSL. None of these need a full IDE or a signup, just a quick, correct answer.
These tools process everything locally in your browser — nothing you paste or upload is sent to a server, which matters when what you're working with is a real API payload, a config file, or anything else you wouldn't want passing through a third party.