Sync with Fastmail

Fastmail is a privacy-focused email provider with full CalDAV support, which makes it a solid host for your 2Do tasks. Fastmail has its own entry in 2Do's Account Type menu, so there are no server addresses or paths to fill in.

Fastmail sync carries the same things as any CalDAV server: all core task fields, multiple alerts, one picture and one audio note per task, and two-way project and sub-task structure. 2Do's grouping features (Smart Lists, tag groups, list groups, unused tags) stay on this device. Each 2Do list is stored on Fastmail as a CalDAV task calendar, the same container under the protocol's own name; see Lists and Task Calendars.

App Password Requirement

Fastmail does not accept your regular account password from third-party apps. It requires an app-specific password to sign in, and your normal password will not work.

Create one for CalDAV access (Fastmail explains these in its App passwords help article):

1. Sign in at fastmail.com and open Settings > Privacy & Security > Integrations (App passwords).
2. Choose New app password.
3. Give it a name you will recognize, such as 2Do, and choose an access scope that includes Calendars (CalDAV).
4. Fastmail shows the password once. Copy it and keep it somewhere safe; you paste it into 2Do next.

Deleting the app password later revokes 2Do's access without changing your main account password.

Setup

1. Open Settings > Sync and stay on the Setup tab.
2. Open Account Type and choose Fastmail.
3. Enter your Email, which is your full Fastmail address, and the app password as the App-Specific Password.
4. Tap Set Up Sync. 2Do connects and discovers your task calendars on the server.
5. Repeat on each device with the same address and password.

Your first sync

When both sides already hold data, 2Do asks how to combine them. Read Merge vs Replace before choosing. You can run any of those choices again later from Settings > Sync > Next sync action; it applies once, then returns to Sync Normally.

Sync Options

With Fastmail connected, the Setup tab adds the CalDAV switches: Sync list ordering, Sync audio notes, Sync pictures, and Sync app preferences, alongside the shared Sync automatically and Push Sync controls.

Daily Sync

2Do syncs when you open it, when iOS grants it background time, and whenever you pull down on the task list.

Troubleshooting

Login or password rejected

Almost always the password type. Make sure what you entered is an app password created in your Fastmail account, with CalDAV access, and not your regular account password. If a password that used to work stops, it may have been revoked; create a new one under Fastmail > Settings > Privacy & Security and enter it again.

Connection succeeds but no task lists appear

Check that the app password's scope includes Calendars (CalDAV). A mail-only scope signs in successfully but exposes no calendar collections.

Adding another device

Install 2Do, choose Fastmail with the same address and app password, and let the first sync pull your data down. See Setting up a new device.

Tips

tip

App passwords can be reused across devices, so one 2Do app password covers your iPhone, iPad, and Mac. Create separate ones per device if you want to be able to revoke them individually.

tip

If you want Smart Lists and tag groups to sync, use iCloud or Dropbox. iCloud carries every attachment type; Dropbox carries picture and audio attachments but not link-only attachments. Fastmail is the better fit when you want your tasks on a CalDAV server you already trust with your mail.