anki-offline-sync

This repository demonstrates how you can use Anki's own sync server to sync data between a computer and a phone.

Some Anki decks are very big (like AnKing which is 3.1GB with all the media). If you have one of these decks, then it would take a lot of time to sync with AnkiWeb, and it's not like everyone's got a good internet connection all the time. For me, while I'm traveling, I lose my network connection temporarily, in such cases it becomes impossible to sync Anki with AnkiDroid. Also, it feels morally wrong to use AnkiWeb's free server to store a very big collection (4GB+). Anki 2.1.57 released its sync server, so you won't have to use AnkiWeb for syncing data, you can directly sync data from your computer to your phone without any third party and it's very fast.

Make sure you have the latest version of Anki Desktop and AnkiDroid. When this tutorial was written the versions were:

Anki Desktop - 2.1.65
AnkiDroid - 2.16.2

This tutorial was written for Windows 11. But I think things are pretty similar for other OSs.

There are many ways to make proxy servers but we will use Node.js with http-proxy because it's easy and the download size is small.

Setting up computer

First install Node.js using the appropriate installer (choose the current version, don't install chocolatey if it asks). After installing open the terminal or command prompt (anywhere) and run these commands to make sure it's installed properly

node -v
npm -v

If running these commands produces no error then you're good to go.

Download this repository and extract it. Open the extracted directory and run this command in the terminal (or command prompt) (NOTE: terminal or cmd should be opened in the extracted directory)

npm i

This command installs the required dependency (http-proxy).

Modifying `index.js`

Before editing the file, you have to find and note down these things

Anki executable path: You have to find where Anki is installed in your system. In my case, it was installed in C:/Users/sarsa/AppData/Local/Programs/Anki/anki.exe. Here's what it would be on other OS (I'm not sure but this is what I've found on the internet)
- Mac: /Applications/Anki.app/Contents/MacOS/anki
- Linux: anki
Host: You would use the IP address of your currently connected network. In Windows 11 you can find it by - WiFi icon on the taskbar > Small right arrow/chevron icon beside the WiFi > Small i icon on the top right corner of the currently connected network > Scroll down to the end then find IPv4 address. This is your host.
Port: Can be any number between 0 and 65536, but I personally prefer 27701. You won't need to do anything about this. You can change this if you're an advanced user. If you're going to change this then replace all 27701 with your port in the next steps.
User: Create a username and a password that you would use for your Anki. It can be anything.

Now edit the file, open index.js in Notepad or VS Code. Find these lines

const ANKI_PATH = ''
const HOST = '0.0.0.0'
const PORT = 27701
const USER = 'username:password'

Set the value of the respective variable. Note, Replace all backslash (\) with slash (/) in ANKI_PATH.

This is what it looked like in my case (example)

const ANKI_PATH = 'C:/Users/sarsa/AppData/Local/Programs/Anki/anki.exe'
const HOST = '42.105.1.208'
const PORT = 27701
const USER = 'sarsa:doanki'

Starting the server

Open terminal or cmd in the current directory then run

node .

If you are using Windows then just double click on start-server.bat to launch the server.

You will see something like

Note down the proxy link (here http://42.105.1.208:27701). You would need it for AnkiDroid.

Setting up Anki desktop

NOTE: Make a backup before you do anything, I am not responsible for any damage it may cause.

Open Tool > Preferences > Syncing. At the very end, you will find Self-hosted sync server, in that input box write http://127.0.0.1:27701

Now the syncing should work on Anki desktop. Do a complete sync. It would ask for AnkiWeb ID and password. Put the username as the AnkiWeb ID and enter the password. In the above example index.js the username is sarsa and the password is doanki

Setting up mobile

On AnkiDroid, go to Sidebar > Settings > Sync > Custom sync server > Sync url. Write down the proxy link (here it was http://42.105.1.208:27701), OK. Also, don't forget to enable the switch on the right side of Sync url.

Return to the homepage of the app. Tap the sync button on the top right side of the screen, it would ask you for the email and password. Put the username in place of the email and enter the password, then Sign in/Log in to sign in. Now the sync should work in AnkiDroid.

FAQs

Q. AnkiDroid is not syncing even though I followed all steps properly. What to do?

Make sure you've enabled "Node.js JavaScript Runtime" to access both private and public networks in your firewall.

Q. Do I have to set it up again if I restart my computer?

No, just follow the "Starting the server" method after the initial setup.

Q. What should I do if my network changes?

Update the HOST in index.js and Sync url to the updated proxy URL in AnkiDroid.

Q. How can I make a local network? I don't have/use a WiFi router.

Just turn on the hotspot on your mobile and connect the computer to your mobile's network. It would make a local network. Turn off the cell data when doing this, so that you don't use cell data and get charged by mistake.

Q. How to turn off the server?

Just close the terminal or cmd window.

Q. More info?

You can read more on the official page

sarsamurmu/anki-offline-sync