Documentation
Everything you need to get the most out of LocalOnly.
Getting started
Pick a tool from the navigation, the all tools page, or the command palette. Paste or drag a file into the input editor and the result appears instantly. Use the toolbar to copy, download, load a sample, or clear.
Keyboard shortcuts
| Shortcut | Action |
|---|---|
| ⌘K | Open the command palette to jump to any tool |
| ⌘F | Find within the active editor |
| Alt+ click | Add a secondary cursor in the editor |
| Tab | Navigate controls; every action is keyboard accessible |
How local processing works
Every tool on LocalOnly is JavaScript that runs in your browser. When you paste a document, it is parsed by code already loaded on the page - there is no request to a server, because there is no server-side component to receive one. The site is a static export, which means what gets deployed is a folder of HTML, CSS and JavaScript with no backend behind it.
You can verify this rather than taking our word for it. Open your browser's developer tools, switch to the Network tab, and use any tool on the site. You will see the initial page and asset loads and nothing else - no request carrying your input. Turning off your network connection entirely and continuing to work is the other easy check.
Working offline
LocalOnlyis a Progressive Web App. After your first visit, a service worker caches the application shell and the editor, so every tool you have opened keeps working with no connection. You can also install it to your home screen or dock from your browser's install prompt, which gives it its own window and launcher icon.
One caveat worth knowing: a tool you have never opened has not been cached, so it needs a connection the first time. If you want a particular set of tools available offline - before a flight, say - open each of them once while connected.
Large files and where the limits are
Tools are built to handle large documents, and because processing is local there are no upload limits or request size caps. Expensive parsing and transforms run without blocking the interface, and the editor renders only the visible portion of a document so scrolling stays smooth regardless of length.
The real constraint is browser memory rather than any limit we impose. A parsed JSON document typically occupies several times the size of its text form, because every string, object and array becomes a separate heap allocation. In practice that means multi-megabyte files are comfortable on a desktop browser, files in the tens of megabytes usually work, and files in the hundreds of megabytes are where you should expect trouble - particularly on a phone or a memory-constrained machine. At that scale a streaming command-line tool such as jq is genuinely the better instrument, because it never holds the whole document in memory at once.
What is stored on your device
A small amount of state is kept in your browser's local storage so the app behaves sensibly between visits: your theme preference, the last tool you used, and per-tool options such as indentation width. None of it is transmitted anywhere, and clearing your browser's site data removes all of it.
Document contents are not persisted. Reloading the page clears the editor, which is deliberate - it means a shared or borrowed machine does not retain whatever you were working on. If you need to keep a result, download it or copy it out before navigating away.
Sharing without a server
Where a tool supports sharing, the link carries the content itself rather than pointing at something we store. The document is compressed, encrypted and placed in the URL fragment - the part after the #, which browsers never send to a server. Anyone with the link can open it; nobody without it can, and we cannot read it either, because it never reaches us.
The practical limit is URL length. Browsers and chat clients truncate very long URLs, so sharing works well for a diagram or a config snippet and not for a multi-megabyte payload.
Browser support
Current versions of Chrome, Edge, Firefox and Safari are all supported, on desktop and mobile. The site needs JavaScript, since the tools are the JavaScript. A few features depend on newer browser APIs - the install prompt, clipboard access, and local diagram rendering - and degrade gracefully where those are unavailable rather than breaking the page.
Privacy
Nothing you enter is ever sent anywhere. Read the full privacy commitment for details on local storage and optional analytics.
Feedback
Have an idea for a tool or spotted a bug? Reach out via the maintainer's LinkedIn, or see the contact page for the right address for each kind of request.