Patterndo has no sign-up and no login. So the question "where is my board saved?" naturally comes up. The answer is that there are three ways to keep a board, and each differs in where it is stored, how long it is kept, and what it is used for. This article compares the address (the ?b= value), the share link (/s/…), and the RAW JSON file, and covers a backup order that keeps you from losing work and what to do when something goes wrong. If you are building your first board, see Getting Started with Patterndo first.
The three methods at a glance
| Item | Address value (?b=) | Share link (/s/…) | RAW JSON file |
|---|---|---|---|
| Stored where | In the address bar itself. Not stored on a server | On a server (shared storage) | A file on your computer |
| How it is made | Automatic. Updated on every edit | The Share button on the top bar | Export RAW in the More menu |
| Retention | As long as you keep the address (bookmark, notes, browser history) | 180 days from the last save | Until you delete the file |
| Strengths | No setup and no personal data left on a server | Short and neat, good to paste into messengers | The surest backup, and you need not worry about link size limits |
| Cautions | For complex circuits the address gets very long | A link with no password, and it disappears after the period | Loading replaces the current board |
Method 1: Saving as the address value
On the /editor screen, every time you place a part or fix wiring, the address bar updates to a long string like /editor?b=…. This string is a compressed form of the board's size, parts, wiring, and power settings, so the address itself is the board. If you bookmark that address or paste it into a notepad, you can open it exactly as it was later, and the board is kept even if you refresh.
- The more complex the circuit, the longer the address. Even a simple board with two parts is around a thousand characters, so for a big circuit, messengers or email can truncate the address. When sharing, a share link is safer.
- The circuit is not sent to a server, so there is less privacy worry. On the other hand, anyone who has the address can see the whole board.
- Even if you arrive through the older address format
/?b=…, you are redirected automatically to the editor address and the same board opens.
Method 2: Share link
Press the Share button on the top bar and then Create link, and a short address, /s/ followed by 10 lowercase letters and digits, is made and copied to the clipboard. The window shows "Created link" and a Copy button so you can copy again, and "Copy share link" and "Create new link" in command search do the same. Whoever receives the link can open the same board without logging in.
After making a link
When you make a link, the address bar changes to the /s/… address. On a shared page, the address bar value is no longer updated automatically, so you have to save your changes yourself.
- If you have not changed anything, the share window says "There are no changes. You can copy the current link." and the Copy link button is available.
- If you changed something, it says "The circuit was modified. Choose whether to overwrite the current link or make a new link." - Save to current link: overwrites the contents of this address with the current circuit. - Create new link: makes a new address and copies it. The contents of the previous link stay as they were.
- On a shared page, you can save directly to the current link with Ctrl+S, and the notice "Saved to the share link." appears.
Note that changes you make on a shared page disappear if you close the tab without saving them.
Retention and limits
- A link is kept for 180 days from when it was made or last saved. Merely opening a link does not extend the period, and if you "Save to current link", another 180 days start from that day.
- There is a limit to the size you can save at once, so a very large board may not be saved. In that case use a RAW JSON file.
- Shared pages are set not to appear in search engines.
Method 3: RAW JSON file
Press Export RAW in the More (⋯) menu and a patterndo.json file is downloaded, with the notice "Exported RAW JSON." This file is human-readable text and holds the board size, parts, wiring, jumpers, net aliases, and power settings. It is saved only on your computer without going through a server, so it is the surest backup.
To reopen it, pick the file with Import RAW in the More menu and press Load in the confirmation window. The window says this: "Replaces the current board with the file. The undo history will be reset." After loading, "Loaded RAW JSON." is shown. If the file is not valid, an error such as "The RAW JSON is not valid." appears and the current board does not change.
Keeping files with the project name and a version in the file name (for example, led-flasher-v2.json) makes it easy to go back to an earlier state. Keeping the files in cloud storage or email is also fine.
Undo and reset
- Undo with Ctrl+Z and redo with Ctrl+Y. This history is kept only while the page stays open and disappears when you refresh or close the tab.
- Reset all in the More menu runs after the confirmation "Removes all parts, wires, jumpers, and net aliases. This action is kept in the undo history." The VCC and GND rails that were drawn at first are erased too, so you have to redraw them to simulate (Using Patterndo Simulation).
A recommended backup order
- While working: the address bar updates automatically, so bookmark it or note the address at important moments.
- At each important stage (wiring finished, right before auto-rewire, and so on): leave a file with Export RAW (Using Auto-Rewire).
- When sharing with others: make a share link and send it. Keep the original RAW file separately.
- Before you start soldering: leaving the final board as a RAW file and a screenshot makes it easy to refer to while soldering.
- Before 180 days pass: for a share link you keep using, open it and "Save to current link" to refresh the period, or move it to a RAW file.
When something goes wrong
| Symptom | Cause | Fix |
|---|---|---|
| A share link shows a "not found" error | 180 days have passed or the address was copied wrongly | Check the address again, and if you have the original, restore it from the RAW file |
| You sent an address but the recipient sees an empty board | The messenger cut off the long address | Use a share link |
| "Failed to copy to the clipboard" | The browser blocked copying | Select and copy directly from "Created link" in the window |
| "Failed to create the share link" | A network problem or a brief server error | Try again shortly, and use a RAW file if urgent |
| Earlier work disappeared after loading | Importing RAW replaces the current board | Save the current board before loading |
| Diagnostic settings reset in another browser | Diagnostic display levels are stored only in the browser | Set them again in settings (Reading Diagnostics Messages) |
Privacy and cookies
Patterndo has no accounts, so it does not collect names or emails. What is stored in a share link is only the board contents (parts, wiring, values, labels). In this browser, only small settings are stored, such as diagnostic display levels, pen settings, and whether you dismissed hint windows. Details are in the Privacy Policy and Ads & Cookies.
Summary
While working, the address value follows you automatically; use a share link to send or publish, and a RAW JSON file to keep something safe for a long time. Just remember that a share link has no password and disappears after 180 days, and that importing RAW replaces the current board, and you avoid most accidents. The control keys are in Patterndo Keyboard Shortcuts, and view switching in 2D and 3D Views.