Sync — Overview

2Do for iOS keeps your tasks in step across devices through a sync service of your choice. We don't run a sync cloud of our own — instead, you pick a service you already trust and 2Do reads and writes through it. The available sync methods are:

• Dropbox — the recommended option. Supports every feature 2Do offers, including attachments, List Groups, Tag Groups, Smart Lists, and Search Presets.
• iCloud CalDAV — Apple-hosted CalDAV sync. Works well for standard tasks, but does not sync every 2Do detail that Dropbox does.
• Custom CalDAV — Fruux, Yahoo!, ownCloud / Nextcloud, Synology, Kerio, Oracle, SabreDAV, and other CalDAV-compatible servers.
• Toodledo — for Toodledo users. Includes web access through toodledo.com, but does not support every 2Do feature. You can also choose No Sync in Settings > Sync if 2Do lives on a single device.

Choose One Method, Use It Everywhere

warning

The single most important rule: every device that runs 2Do must use the same sync method. Mixing methods (e.g. Dropbox on Mac, iCloud CalDAV on iPhone) leads to disconnected datasets. Pick one, set it up the same on every device, and only then start using 2Do day-to-day.

At-a-Glance Comparison

	Dropbox	iCloud CalDAV	Custom CalDAV	Toodledo
Recommended	✅
All task properties	✅	partial	partial	partial
Attachments	✅	one picture + one audio	one picture + one audio
List Groups	✅
Tag Groups	✅
Smart Lists	✅
Search Presets	✅
Automatic background sync	✅	✅	✅	manual only
Web access			varies	toodledo.com
Cross-platform (iOS / Mac / Android)	✅	✅	✅	✅

note

Dropbox is the best choice if you use every 2Do feature or lots of attachments. CalDAV sync is great for standard tasks, but it does not sync every 2Do detail that Dropbox does. Toodledo does not sync attachments.

Setting Up a New Device

When you install 2Do on a brand-new iPhone or iPad and sign in to a sync service that already has your data:

1. Open Settings > Sync and pick the same sync method you've been using on your other devices.

2. Sign in with the same account.

3. When 2Do asks how to proceed on first sync, choose Replace local data — this pulls everything from the cloud down to the new device, leaving the cloud copy untouched. When you've just restored from a backup and your device now has the freshest data:

4. Set up sync the same way.

5. On first sync, choose Replace server data — this pushes your restored data up, replacing whatever's currently in the cloud. If you're unsure which side has the freshest data, share or export a backup first (Settings > Backups > Backup to Email) before connecting sync, so you have a recovery point either way.

Replace server data vs Replace local data

When you connect a new device or reset sync, 2Do may ask whether to:

• Replace server data — push your local 2Do tasks up to the sync service. Use this when 2Do has the right data and the server is empty or out of date.
• Replace local data — pull tasks from the server down to this device. Use this when the server has the right data and your local 2Do data is empty or out of date.

Choosing this manually at any time

Beyond the first-sync prompt, you can switch the next sync's behavior any time under Settings > Sync > Next Sync Action. Dropbox and CalDAV offer Sync normally, Replace server data, and Replace local data. Toodledo offers Sync normally, Replace local data, and Merge sync. After the sync completes, the option resets to Sync normally automatically.

warning

Pick the wrong direction and you can lose data. If your device is empty and you choose Replace server data, your empty database will overwrite a populated server. Always pause and think about which side has the data you want to keep.

If your device is empty and you choose Replace server data, the empty device can overwrite the cloud copy.

Switching Sync Methods

To change methods (for example, iCloud CalDAV → Dropbox):

1. Share a backup from Settings > Backups > Backup to Email as a safety net.
2. Disconnect the current method on each device.
3. Connect the new method on one device first and let it populate.
4. Connect the others, choosing Replace local data to pull from the freshly populated server.

Background Sync on iOS

iOS controls when background apps may run. 2Do uses Apple's Background App Refresh and silent push to stay current; you can also pull-to-refresh on the Lists screen to force a sync. If sync feels stale:

• iOS Settings > General > Background App Refresh > 2Do — make sure it's on.
• Don't force-quit 2Do. Force-quitting tells iOS not to wake the app in the background.
• On poor connections or heavy data days, iOS may delay refresh cycles. Learn more in 2Do not syncing properly in the background.