Background Auto Sync for Anki Addon

Anki Add-ons
1

Background Auto Sync for Anki

Automatically syncs your Anki collection in the background — without stealing focus, raising windows, or interrupting your workflow.

Install from anki web

This addon is a fork of Auto-Sync-Anki-Addon by Robin-Haupt-1.

Features

  • True background sync — If Anki is minimized, it stays minimized. If another app has focus, Anki won’t steal it. The sync happens silently.
  • Periodic sync — Automatically syncs after a configurable period of inactivity (default: 1 minute after last interaction).
  • Idle periodic sync — While you’re away, keeps syncing periodically (default: Off) to pick up changes from AnkiWeb, mobile, or other devices.
  • Change detection — Only syncs when the collection has actually been modified (cards added, reviewed, edited). Stops wasting bandwidth when nothing changed (enabled by default).
  • Idle-before-sync delay — When a change is detected, waits for a configurable idle period before syncing, so it doesn’t interrupt an active editing session (default: 2 minutes).
  • Strictly avoid interruptions — Won’t sync while you’re reviewing cards, browsing, or have any Anki dialog open (enabled by default).
  • Log window — View a timestamped log of all sync activity for debugging.

Installation

  1. Download the latest .ankiaddon from Releases.
  2. In Anki, go to Tools → Add-ons → Install from file… and select the downloaded file.
  3. Restart Anki.

Or install via AnkiWeb addon code (226796325).

Configuration

Go to Tools → Background Auto Sync Options… to configure:

Option Default Description
Sync after 1 minute Minutes of inactivity before triggering a sync (disabled if Change mode is On)
When idle, sync every Off Periodic sync interval while Anki is idle (disabled if Change mode is On)
Strictly avoid interruptions :white_check_mark: On Skip sync during reviews, browsing, or when Anki has focus
Only sync when changes detected :white_check_mark: On Skip idle periodic syncs if no local changes since last sync
Wait idle before syncing after change 2 minutes After detecting a change, wait this long idle before syncing

Tip: You can restore these optimal defaults at any time using the Reset Defaults button in the options menu.

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Background Sync Behavior

The addon ensures syncs never interrupt your work:

  • If Anki is minimized → stays minimized during and after sync
  • If Anki is behind other windows → stays behind, doesn’t raise to foreground
  • If another app has focus → Anki won’t steal focus
  • Window state is saved before sync and restored after sync completes

How It Works

  1. After user activity in Anki, a countdown timer starts.
  2. Once the idle timeout expires, the addon checks:
    • Is Anki in a “safe” state? (no dialogs open, not reviewing, etc.)
    • Is there internet connectivity?
    • If change-only mode: has the collection been modified?
  3. Window state is saved (minimized? focused? background?).
  4. Sync triggers via Anki’s built-in sync.
  5. After sync completes, window state is restored exactly.
  6. The cycle restarts.

License

GPL-3.0 — see LICENSE.txt.

1 Like
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You need to sync when you open the app on a device, and sync when you close/leave the app on that device. That’s it. So aside from being unnecessary, this add-on should be more explicit about a few things –

  1. Syncing terminates your “undo”-queue. “Periodic sync” may mean that when you come back in a couple minutes, you can’t undo something you did just before you took a break.

  2. Allowing this to auto-sync your collection on one device while you are using/editing/studying your collection on another device can lead to sync conflicts. “Idle periodic sync” seems like it’s likely to cause issues, especially for users who leave Anki open and who have other add-ons with background activity.

1 Like
3

You are right Updated the addon readme

Important Considerations

  • Undo Queue: Syncing terminates Anki’s “undo” queue. Periodic sync may mean that if you take a break and return, you won’t be able to undo actions performed just before the break.
  • Sync Conflicts: Auto-syncing on one device while actively using, editing, or studying on another device can lead to sync conflicts.
  • Idle Periodic Sync: Using “Idle periodic sync” while leaving Anki open may cause issues, especially if other add-ons with background activity are installed.
1 Like
4

The original Auto Sync the fork of OP has been around since 2021 and is a relatively popular add-on up (rate +24/-2). So far probably no users have reported issues with undo or conflicts in the add-on’s comments or on GitHub.