Hi Product Hunt! 👋 I'm the maker of usepreciso and I want to explain why I built this instead of just using the dozens of similar tools that already exist. Every day I paste JWTs into decoders, format JSON payloads, and run word counts on private documents. I kept asking myself: where does this data actually go? Most tools send it to a server. In 2026, some feed it into AI models. I wanted a set of tools where that question simply doesn't arise, because nothing leaves the browser in the first place. Not because of a privacy policy (anyone can write one). Because there is no server call to make. 🔒 Why usepreciso is different: • Everything runs in JavaScript in your browser tab • No account required - ever • No trackers, no analytics on what you type • Your JWT, your JSON, your private documents stay yours • Works offline after first load • Free forever In the age of AI, data privacy isn't just a feature, it's the only promise a utility tool can actually keep. ⚡ A few things I'm proud of: • The DST tracker covers 68 countries currently observing DST, plus full historical data for 72 that stopped, including exactly when, why, and what offset they moved to • The kids site locks to fullscreen so toddlers can't accidentally close games. The 2-second hold to exit wasn't a clever UX decision, it was survival (my daughter is 2) • The chart generator accepts CSV, Excel and JSON, upload a spreadsheet and get a chart in seconds This is a solo build. I'd genuinely love your feedback, especially on tools that feel half-baked, things that are missing, or anything that doesn't work the way you'd expect. Thank you for checking it out 🙏

usepreciso

Free browser tools - your data never leaves your device

Free browser tools - your data never leaves your device