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Privacy-First Developer Tools. Everything Runs Locally.
LocalOnly is a privacy-first developer toolkit that bundles 37+ focused utilities - JSON formatting, validation, conversion and inspection, plus everyday encoders, generators and converters - into one fast, consistent, keyboard-driven app. Everything runs in your browser, so your data never leaves your machine.
We want developers to have great tools without having to trade away their privacy to use them. The mission is simple: build the utilities you reach for every day, make them fast and free, and guarantee that the data you paste stays on your device. No exceptions, no fine print.
Most online developer tools quietly send whatever you paste to a server to do the work. That is a real problem when your JSON contains API keys, access tokens, personal data or proprietary payloads. You often cannot tell whether that data is logged, cached, analysed or retained. We built LocalOnly because that trade-off is unnecessary: modern browsers are more than capable of doing the work locally, with no server involved at all.
Privacy here is not a checkbox - it is the foundation. There are no accounts, no logins and no analytics tracking the content you process. We do not store, transmit or inspect your input. The site is kept running through unobtrusive ads, never by monetising your data.
Every transformation runs locally in JavaScript, often on a background Web Worker so the interface stays smooth. Because there is no processing server, there is no upload step and no file-size ceiling imposed by an endpoint - your machine is the only limit. The entire app is a static export and an installable Progressive Web App, so once loaded it keeps working offline, on a plane or behind a strict firewall.
Speed is a feature. Heavy work is offloaded to Web Workers, and debouncing plus virtualization keep the interface responsive even with multi-megabyte JSON. Pages are built for excellent Core Web Vitals, with instant navigation and near-instant tool launches thanks to local caching.
A browser-only architecture removes whole categories of risk - there is no database to breach and no server logs holding your data. On top of that, the deployed site ships with strict security headers and a tight content policy. Learn more on the Security page.
Good tools work for everyone. LocalOnly is built to WCAG-AA standards, with full keyboard navigation, a command palette, sensible focus order, semantic markup and screen-reader support. We treat accessibility as an ongoing commitment, not a one-time task.
LocalOnly started with JSON and is growing into a complete privacy-first developer toolbox - more converters, more encoders, local-only sharing and broader language support are all planned. See where we are headed on the Roadmap. LocalOnly is an independent, privacy-first product.
Ready to try it? Browse tools or get in touch via Contact.