Tasks CalDAV Sync

Bidirectional sync between obsidian-tasks and any CalDAV server (Nextcloud, Radicale, Baïkal, Fastmail, etc.).

Works with the obsidian-tasks plugin — syncs task status, dates, priorities, recurrence, tags, and notes as standard VTODO items.

Features

• Multi-calendar support — sync different tags to different calendars and servers (tasks must have the tag on both sides — Obsidian #tag and CalDAV CATEGORIES)
• Bidirectional sync — push tasks to CalDAV servers and pull changes back
• Auto-sync — configurable interval (default: 5 minutes)
• Dry-run mode — preview what will sync before committing changes
• Conflict detection — manual resolution or auto-resolve with Obsidian wins
• Task notes — indented bullet points below a task round-trip as VTODO DESCRIPTION
• Recurrence — RRULE round-trips between CalDAV and obsidian-tasks format
• Delete detection — three-way diff detects deletions on either side
• Reconciliation — automatically matches identical tasks when switching calendars or after lost sync data, preventing duplicates

Requirements

• Obsidian v0.15.0+
• obsidian-tasks plugin (must be installed and enabled)
• A CalDAV server with VTODO support

Installation

From Community Plugins (recommended)

Available in the Obsidian community plugin directory:

1. Open Settings → Community plugins → Browse
2. Search for "Tasks CalDAV Sync"
3. Click Install, then Enable

Using BRAT (for beta releases)

1. Install the BRAT plugin
2. Open BRAT settings → Add Beta Plugin
3. Enter josecoelho/obsidian-tasks-caldav and click Add Plugin
4. Enable "Tasks CalDAV Sync" in Settings → Community Plugins

BRAT will also handle future updates automatically.

Manual

1. Download main.js, manifest.json, and styles.css (if present) from the latest release
2. Create VaultFolder/.obsidian/plugins/obsidian-tasks-caldav/
3. Copy the downloaded files into that folder
4. Restart Obsidian and enable the plugin in Settings → Community Plugins

Configuration

Open Settings → Tasks CalDAV Sync. Add one or more calendars, each with:

Setting	Description
Tag	Only tasks with this tag are synced — on both sides (Obsidian tags and CalDAV CATEGORIES must match)
Calendar name	Name of the calendar on the server
Server URL	CalDAV server endpoint
Username / Password	CalDAV credentials

Global settings:

Setting	Description	Default
Sync interval	Auto-sync period in minutes	5
New tasks destination	File where incoming CalDAV tasks are created	Inbox.md
New tasks section	Optional heading within the destination file	—
Sync completed tasks	Include completed tasks in sync	off
Delete behavior	What happens when a task is deleted on one side	ask

Conflict resolution

Two modes:

• Manual (default) — sync pauses when conflicts are detected, requiring review
• Auto-resolve Obsidian wins — automatically keeps the Obsidian version on conflict

Usage

Commands

Open the command palette (Ctrl/Cmd + P) to access:

Command	Description
Sync with CalDAV now	Run an immediate sync
Preview sync (dry run)	See what would change without applying
View sync status	Show last sync time and any conflicts
Inject task IDs	Add unique IDs to selected tasks
Validate task IDs	Check document for valid/invalid task IDs

Task IDs

Each synced task needs a unique ID. The plugin uses the obsidian-tasks native format:

- [ ] Buy groceries 🆔 20260213-a1b

Use the "Inject task IDs" command to add IDs to existing tasks, or the plugin will assign them automatically during sync.

Metadata mapping

Obsidian	CalDAV	Direction
Task text	SUMMARY	↔
Indented bullets	DESCRIPTION	↔
📅 due date	DUE	↔
🛫 start date	DTSTART	↔
✅ done date	COMPLETED	↔
🔁 recurrence	RRULE	↔
Priority emoji	PRIORITY (1-9)	↔
Tags	CATEGORIES	↔
Status (done/cancelled)	STATUS	↔

Task notes

Indented bullet points below a task are synced as the VTODO DESCRIPTION field:

- [ ] Plan vacation 🆔 20260213-x2c
    - Research flights
    - Book hotel
    - Pack list

These notes round-trip to/from CalDAV clients like Thunderbird or Tasks.org.

Troubleshooting

Sync reports success but nothing changes

The Tag setting is a hard filter on both sides, not just routing:

• Obsidian → CalDAV — only tasks carrying the Obsidian #tag are pushed
• CalDAV → Obsidian — only server VTODOs whose CATEGORIES include that tag are pulled

If your server tasks have no matching CATEGORIES, sync completes successfully but pulls nothing ("No tasks"). To sync everything regardless of category, leave the Tag field empty.

Known limitations

• Priority round-trip is lossy — obsidian-tasks uses emoji-based priorities (⏫🔼🔽) while CalDAV uses numeric PRIORITY (1-9). Obsidian→CalDAV maps correctly, but CalDAV→Obsidian does not write priority emojis back into the task markdown.
• Internal obsidian-tasks API — This plugin accesses obsidian-tasks' internal getTasks() method, which is not part of the official public API. Future obsidian-tasks updates could break this integration.

Tested CalDAV servers

Server	Coverage
Radicale	Automated E2E suite
Nextcloud	Automated E2E suite
Vikunja	Automated E2E suite
Baïkal (SabreDAV)	Automated E2E suite
Fastmail	Manually verified

Should work with any CalDAV server that supports VTODO, such as Synology.

iCloud

iCloud Reminders is not supported directly — Apple does not expose it as a standard CalDAV/VTODO backend, so sync fails at later steps even with the correct server URL (#74).

Workaround: sync Obsidian with a standards-compliant CalDAV account (e.g. fruux) and add that same account to the iOS Reminders app. Reported working by @Jane2100117.

Development

npm i            # install dependencies
npm run dev      # watch mode
npm run build    # production build with type checking
npm test         # run all tests (unit + E2E, requires Docker for Radicale)
npm run test:wdio  # run Obsidian smoke tests (requires Docker + downloads Obsidian binary on first run)

See CLAUDE.md for architecture details and testing guidelines.

License

MIT