A web page can store data on your device without a server, an account or a login. That is local storage, and it is what lets a browser notepad remember what you typed.
The trade is exact: nothing is transmitted, and nothing is guaranteed to survive.
What it is good for
Anything you would write on paper next to the keyboard. A scratchpad, a list you are assembling, notes during a call, text you are drafting before pasting it somewhere else.
Because nothing leaves the browser, it suits things you would not put in a shared document — and there is no account to create, which is most of the appeal.
What clears it
| Cause | Likelihood |
|---|---|
| Clearing browsing data | whenever you do it |
| Private or incognito window | always, on closing |
| iOS Safari, site unvisited 7 days | automatic |
| Browser storage pressure | occasionally |
| A different browser or device | it was never there |
The iOS rule is the one that surprises people. Safari deletes local storage for any site not visited in seven days, as an anti-tracking measure. It is not a fault and there is no way for a site to opt out.
The last row matters as much: storage is per-browser and per-device. Open the same page on your phone and it is empty, because that is a different store. There is no sync without a server, and a server is the thing being avoided.
How much fits
Roughly five megabytes per site in most browsers, shared across everything that site stores. For text that is about two million characters — far more than anyone types into a scratchpad.
Exceeding it throws an error rather than silently truncating, which is the right behaviour but only helps if the page notices and tells you.
Why saving is delayed
Writing to local storage is synchronous: it blocks the page while it happens. On a short note that is imperceptible. On a document of several thousand words, doing it on every keystroke produces a stutter while typing.
Waiting a fraction of a second after you stop typing removes that entirely, at the cost of losing at most the last few characters if the tab closes at exactly the wrong moment.
Questions people ask
Can the site owner read what I typed? Not from local storage. It never leaves the browser unless the page explicitly sends it, which is a different thing that would show in the network tab.
Is it encrypted? No. Anyone with access to your unlocked device and browser profile can read it. It is private from the network, not from the person holding your laptop.
What is the difference from a cookie? Cookies are sent to the server with every request; local storage never is. For storing data locally, local storage is both larger and more private.
How do I keep something permanently? Download it. That is the only answer.
The online notepad keeps text in this browser and says plainly what clears it, and the word counter and character counter handle the counting once you have written something.