How offline saving works - Offline Boards

What happens when you type

You change something. You add a note, drag one, draw a stroke or edit text. The board in memory updates instantly.
The page waits a moment. A fraction of a second after you stop, it turns the whole board into a small block of JSON text.
Your browser stores it. The text is written to your browser's local storage, a small key-value area that every site gets for itself on your device.
Next visit, it reads it back. When you open the board again, the page looks for that text, checks that it is valid, and rebuilds your notes and drawing.

No step involves the network. The badge in the board's top bar says Saved in this browser with the time of the last write. If your browser refuses the write, the badge changes to a warning and the board keeps working from memory until you close the tab.

Where your board lives

Browser storage is kept per browser profile and per site address. That has a few practical consequences worth knowing before you rely on a board.

One browser, one board. Chrome and Safari on the same laptop do not share boards. Neither do two profiles in the same browser.
One address, one board. If you open the page from a different address, for example from a saved copy on your disk instead of a hosted copy, your browser treats it as a different site and shows a different, empty board.
One saved slot. The full board uses a single saved slot, plus one extra copy of whatever you replaced last, so you can step back from a template or an import you regret.
The demo is separate. The live board on the home page keeps its own copy and never touches your full board.

What can erase it

Because the board is only in your browser, anything that empties the browser's storage for this site empties the board.

Clearing cookies and site data, or choosing "clear history" with site data ticked.
Working in a private or incognito window. The board lasts until that window closes.
Browser settings that delete site data whenever you quit.
Resetting, reinstalling or switching browsers, or moving to a new computer.
Browsers that tidy up storage for sites you have not visited in a while, or when the device is very short on space.

There is no recovery from our side, because there is no copy on our side. The only safety net is an export you made yourself.

Your board, right now

This reads the saved copy of your full board from this browser. It does not leave the page.

Notes: 0
Strokes: 0
Saved size: 0 KB
Last saved: Not saved yet
Stored in: This browser (localStorage)

The bar compares your board with 5 MB, a common size for this kind of storage. The real allowance depends on your browser and can be smaller or larger.

No board is saved yet, so the numbers are zero. Open the board and add a note to see them change.

Backing up and moving boards

Use Export / import in the board's top bar. You can download a .json file, or copy the same text and paste it somewhere safe. To bring a board back, or to open it on another device, choose the file or paste the text, and pick whether it replaces the current board or sits beside it.

Imports are checked before anything changes. Anything that is not valid JSON, or does not look like a board, is rejected with a message, and items with impossible values are skipped and counted. Very large files are refused rather than freezing the page. A good habit is to export after any session you would hate to lose.

Because the file is plain JSON, it is easy to keep in a folder, attach to an email you send yourself, or store with other project files.

The limits

Here is what you get, and where it stops.

What you get

An unbounded canvas with pan, zoom, fit and a mini-map.
Sticky notes in four colors, freehand ink in three, and undo for up to sixty steps in a visit.
Autosave to your browser, with a visible saved or not-saved badge.
Export and import as JSON, and three starter templates.
Full keyboard control, including a keyboard pen.
Printing the part of the board you can see, using your browser's print command.

What you do not get

Sync between devices. There is no account and no server.
Real-time collaboration or sharing links.
Images, files or links pasted onto the board. Notes hold text only.
A history of old versions. Undo is lost when you close the tab.
Unlimited size. A board holds up to 1,500 notes and 3,000 strokes, and browsers cap storage per site, often at a few megabytes.
Safe editing in two tabs at once. The last tab to save wins, and the board warns you when another tab has changed it.

Privacy, checked by you

Offline Boards has no accounts, no analytics and no advertising. It loads one page, one stylesheet and one script, and then it does not talk to anything. It does not set cookies. The only thing it writes is your board, plus a tiny preference for how the mouse wheel behaves.

You do not have to take our word for it. Open your browser's developer tools, switch to the network tab, and use the board for a while. You will see no requests after the page has loaded. For a stronger test, turn Wi-Fi off and keep working.

One caution: browser extensions, shared computers and device backups can still see or copy what is stored in your browser. If a board is sensitive, treat it like any other file on that device.

Questions

Can I reload the page with no internet at all?

Once the page is open you can switch the connection off and keep working. Reloading while offline works only if your browser still has the page in its cache, or you opened a local copy of the files. This site does not install a service worker, so we cannot promise a cold start with no connection.

Can I run it from a file on my own computer?

Yes. The site is plain HTML, CSS and one script, so it opens from a folder. Some browsers give local files stricter or separate storage, and a few refuse to persist it, so run the check above and export regularly.

What happens if the browser says storage is full?

The badge turns into a warning and the board keeps working from memory. Export it straight away, then remove some notes or ink. Imports and templates stop adding items once a board reaches its size limits, so check the result after a large import.

Does it work on a phone or tablet?

Yes. Drag with one finger to move notes, use the hand tool to pan, pinch to zoom and double-tap empty space to add a note. Storage rules on mobile browsers are the same as on desktop, so private tabs lose boards when closed.

Is the board encrypted?

No. It is stored as readable JSON in your browser's storage, protected by whatever protects the rest of your browser profile. Do not use it as a vault for passwords or secrets.