Nextcloud Sync for Obsidian

Good news for anyone working across multiple desktops and mobile devices.

The only cost you pay is waiting for the initial Vault index to complete on first install. From that moment on, you get:

• Your writing is never lost — the merge logic keeps your Vault in a clean, consistent state even when the same note is edited on multiple devices at once.
• Sync fades into the background — Nextcloud's fast differential sync means you'll stop noticing sync time altogether.
• Works beyond Nextcloud too — with slightly reduced features, it works against any standard WebDAV server as well.

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Bidirectional sync between your Obsidian Vault and Nextcloud — built specifically for Nextcloud, not just generic WebDAV.

Most "WebDAV sync" plugins treat the server as a dumb file store: they compare modification times, copy files, and hope for the best. Nextcloud Sync instead talks to Nextcloud's own APIs (Capabilities, file IDs, checksums, versions, locking, Login Flow v2) to make syncing safe, fast, and frictionless — while still degrading gracefully to plain WebDAV when those APIs aren't available.

A Japanese translation is available at README.ja.md.

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💬 Your feedback shapes this plugin

This plugin is still young and some behaviour can be rough around the edges. Please tell me what you run into — it genuinely helps. Whether something broke, something's missing, or you just have a thought after using it, I'd love to hear from you (impressions especially make my day!):

• 🐛 Report a bug → GitHub Issues
• 🙋‍♂️ Request a feature / share your impressions → GitHub Discussions

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What's new in this release (0.7.9)

• Fix: notes with very long names failed to sync onto Android (0.7.9) — files whose name was within the filesystem limit could still fail to download with a FILE_NOTCREATED error, because the temporary file used during writing added a suffix that pushed the name over the 255-byte limit (Japanese titles hit this around 80 characters). The temporary file now uses a short fixed-length name, so any note whose own name fits is written reliably; a name that genuinely exceeds the limit now reports a clear "file name too long" message instead of an opaque error.

For the full version history of every release, see the changelog.

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Why Nextcloud-specific? (vs. generic WebDAV)

Concern	Generic WebDAV plugin	Nextcloud Sync
Change detection	Modification time (clock-skew prone, false re-uploads)	Content hash + Nextcloud sync-token / checksums capability for true differential sync
Rename / move	Delete + re-create (loses history, re-downloads everywhere)	File-ID (OC-FileId) tracking — a rename stays a rename on every device, history preserved
Deletion safety	Hard delete	Routed through the Nextcloud trashbin — recoverable, never an irreversible DELETE
Setup	Manual app-password copy & paste	Login Flow v2 — approve in the browser, credentials are issued and stored automatically
Large files	Skipped or fail on a single PUT	Chunked upload — split, resumable, checksum-verified
Concurrent edits	Hope nobody else writes	Optimistic concurrency — every update carries an If-Match precondition, so a remote changed by another device is turned into a conflict (no lost update) without locking round trips; server-side Files Locking stays available as an opt-in
Recovery from mistakes	None (your copy is all you have)	Server version history — browse and restore any past revision from inside Obsidian
Server unavailable	Cryptic errors / partial writes	Maintenance-mode detection (/status.php) and parsed Nextcloud error messages
Capability awareness	None	Capabilities probing (/ocs/.../capabilities) — features light up only when the server supports them (Progressive Enhancement)

If you point it at a non-Nextcloud WebDAV server, it automatically disables the Nextcloud-only features and falls back to standard recursive WebDAV sync — so it still works, just without the extras.

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Features

Core sync

• Bidirectional sync between Obsidian and Nextcloud.
• Hash-based differential sync — only changed files are transferred (no full rescans), so a 1,000-file Vault settles in seconds.
• Atomic writes — a download interrupted mid-transfer never leaves a half-written or 0-byte file in your Vault.
• Rename / move tracking via Nextcloud file IDs — moving a note doesn't re-upload it everywhere.
• Trashbin deletes — remote deletions use the Nextcloud trashbin (recoverable). When a deletion is applied to your local Vault, it follows your Obsidian "Deleted files" setting (system trash / move to .trash / permanently delete) rather than forcing one behavior; folders and files outside the Vault's tracked notes (e.g. config-folder files) are handled too.
• Per-Vault configuration — each Vault can target a different Nextcloud server / account without state bleeding between them.
• Periodic auto-sync with a configurable interval (set to 0 for manual-only), plus a Sync now command.
• Sync on file change (watch mode) — optionally sync immediately after you edit a local file (debounced ~2s after you stop typing). Toggle on/off in settings; works alongside the periodic interval.
• Resilient retries — failed files are skipped, queued, and retried next sync with exponential backoff; a dropped Wi-Fi connection resumes automatically.
• Standard WebDAV fallback — works against any WebDAV server (recursive), Nextcloud features auto-disabled.
• Filter the sync-status dialog by status — the status dialog has a checkbox row (Uploaded, Downloaded, Deleted, Merged, Conflicted, Local wins, Remote wins, Error) so you can focus on, say, only conflicts. All on by default; your selection is saved and persists across Obsidian restarts, and applies to every section.
• Compare a file with its remote version (opt-in) — enable "Compare with remote (explorer menu)" in settings, then right-click any file in the explorer to open a popup comparing local vs remote modification time, checksum (with a match/mismatch badge), and a line diff. Resolve the difference right there with push (overwrite remote with local) or pull (overwrite local with remote), each behind a confirmation. The toggle takes effect immediately — no restart.
• Per-device logging — two opt-in logs, written to a folder you pick (a fuzzy folder picker; defaults to the vault root) and named per device so multiple devices never overwrite one another:
  • Sync log (nextcloud-sync_sync_<device>.txt) — one appended block per sync with the plugin version and all merge-related settings in the header, then one line per operation showing the marker, path, local/remote checksums and sizes. A level switch records important events only (conflicts, merges, side-wins, errors) or all operations.
  • Debug log (nextcloud-sync_debug_<device>.txt) — a timestamped diagnostic log with selectable verbosity (error / debug / verbose), the plugin version, and a snapshot of all settings. Useful for troubleshooting on mobile where there's no console. Turn it off and delete the file when finished.
• Reset the Vault index (Settings → Maintenance) — clear this device's sync tracking index back to its first-install state (behind a confirmation) so the next sync re-scans everything. No Vault or remote files are deleted; use it to recover from inconsistent sync state.

Conflict safety (never lose content)

• Auto-merge (reconcile-text / diff3) for edits in different regions, including YAML frontmatter when the two sides changed non-overlapping lines (on by default).
• Merge scope by extension — only files with a configurable extension (default md, txt) are text-merged; other files (images, PDFs, binaries) are never merged and never get markers written into them.
• Conflict-resolution policy for anything that can't be cleanly merged: Error (leave both sides untouched, report it, and retry next sync — the default), Local wins (overwrite remote with local), Remote wins (overwrite local with remote), or Conflict markers (Git-style <<<<<<< LOCAL / ======= / >>>>>>> REMOTE written into the file; text files only — other files fall back to Error).
• Conflict badge in the status bar showing the count of unresolved conflicts (clears to normal at zero; pairs well with a #conflict tag search).

Nextcloud power features

• Login Flow v2 — set up with a browser approval instead of manually issuing and pasting an app password. Credentials are stored in Obsidian's secret credentials store, never in plain text in data.json.
• Server version history — for the active note, list every revision the server holds (newest first) and restore any of them atomically, with confirmation. The restored content syncs back cleanly without triggering an infinite conflict loop.
• Chunked upload — large attachments (images, PDFs, audio) above the chunk threshold are split and uploaded resumably; interrupted uploads never publish a partial file, and completion is checksum-verified. A separate absolute maxFileSizeMB cap guards memory.
• Files Locking (experimental, off by default) — optionally acquires a per-file server lock immediately before each update and releases it right after. Default off: lost-update safety is provided instead by an always-on If-Match precondition (a remote changed by another client returns 412, which the engine turns into a conflict), avoiding the extra LOCK/UNLOCK round trips per file. Enable it for belt-and-suspenders locking; requires the Nextcloud files-locking app and stays inactive when the app is absent.

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Mobile (iOS / Android)

Mobile is supported, with a few platform-aware differences (desktop behaviour is unchanged):

• Automatic sync is off by default on mobile. The OS suspends background timers, so periodic auto-sync and "sync on file change" are disabled (greyed out). Use Sync now, or enable Sync on startup (off by default on mobile) to sync once a few seconds after the app opens.
• Sync on startup is a new setting on both platforms (desktop: on, 1 s; mobile: off).
• Large files are skipped on mobile above the "Maximum file size" limit (set 0 for unlimited) to avoid out-of-memory crashes; skips are reported.
• No progress UI on mobile — only error notices are shown.
• Network concurrency is configurable; its first-run default is derived from the device's available memory — uniformly on desktop and mobile, with no platform-specific branch: 16 with 8 GB of RAM or more, 8 at 4 GB or more, 4 below that, and 3 when the device doesn't report its memory (common on mobile). Transfers run with bounded parallelism — capped both by this count and by a total in-flight-bytes budget (smaller on mobile) so large files can't exhaust memory — and uploads to the same folder are serialized to avoid server lock contention.
• Sync on Wi-Fi only skips on cellular (Android/desktop). Not available on iOS (no network-type API), where the toggle is disabled.
• Sync now shows a result notice on mobile (uploads / downloads / conflicts, or "already up to date") since there's no status bar. Tapping it while not signed in stays disabled, and the settings screen shows a clear "not signed in yet" banner.
• Debug mode (diagnostic log) is available on mobile and does not change syncing.

Requirements

• Obsidian 1.11.4 or later (the plugin uses the secret-storage API introduced in 1.11.4). Desktop (Electron) and mobile (iOS / Android) are supported.
• Nextcloud Hub 26 "Winter" (server 33) or later is recommended for the Nextcloud-specific features. Older Nextcloud servers are no longer blocked — they still connect and sync, but the settings screen shows a recommendation banner and some features may degrade. Plain WebDAV servers fall back to core sync.
• A Nextcloud account. You can authenticate with Login Flow v2 (recommended) or a manually issued app password (never your main password).

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Installation

From the Community Plugins browser (recommended)

1. In Obsidian, open Settings → Community plugins.
2. Disable Restricted mode, click Browse, and search for Nextcloud Sync.
3. Install, then Enable.

Manual installation

1. Download main.js and manifest.json (and styles.css if present) from the latest GitHub Release.
2. Copy them into <YourVault>/.obsidian/plugins/nextcloud-sync/.
3. Reload Obsidian and enable Nextcloud Sync under Settings → Community plugins.

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Getting started

1. Open Settings → Nextcloud Sync.
2. Enter your Server URL (e.g. https://cloud.example.com).
3. Authenticate:
   • Recommended: click Login with browser (Login Flow v2), approve in the browser, and credentials are filled in and stored automatically; or
   • enter your username and a manually issued app password.
4. (Optional) Adjust the auto-sync interval, Sync on file change (watch mode), auto-merge, chunk threshold, and locking options.
5. Run the Sync now command (or wait for the periodic sync). The first run performs a full scan of your Vault and the remote, then transfers what's needed; subsequent syncs are incremental.

Your Vault is synced into a folder named after the Vault on the Nextcloud side, keeping multiple Vaults cleanly separated.

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Enabling Nextcloud server-side features

Two power features depend on server-side Nextcloud apps. Each only needs to be enabled once by a Nextcloud administrator. The plugin detects them through the capabilities API — if an app is missing, the corresponding feature simply stays inactive (no error).

File Locking

Locking uses Nextcloud's Temporary files lock app (app ID files_lock, available since Nextcloud 24; bundled with Nextcloud Hub from v34).

• Web UI (admin): sign in as an administrator → profile menu (top-right) → Apps → search for Temporary files lock → Enable (download it first if it isn't installed).
• Command line (occ) — run as the web-server user (often www-data):

  sudo -u www-data php /var/www/nextcloud/occ app:enable files_lock

• Then enable File Locking (Experimental) in the plugin settings and re-sync. (Docker: docker exec -u www-data <container> php occ app:enable files_lock.)

Version history

Server-side versions come from the built-in Versions app (app ID files_versions), which is enabled by default on a standard Nextcloud install — usually nothing to do.

• If it was disabled, re-enable it: Apps → Versions → Enable, or:

  sudo -u www-data php /var/www/nextcloud/occ app:enable files_versions

• Versions are created automatically as files change; browse and restore them with the Show version history command in Obsidian.
• A note must have been changed on the server at least once for prior revisions to exist. Retention is configured server-side by the admin (versions_retention_obligation in config.php).

Other settings worth checking

These are not strictly required, but on self-hosted instances they often need attention for smooth, reliable syncing. All are server-side (admin) settings.

• Trusted domains — the host you connect to must be listed in trusted_domains in config.php, otherwise the server rejects requests. Add your domain/IP if needed.
• HTTPS & reverse proxy (important for Login Flow v2) — behind a reverse proxy, set overwriteprotocol => 'https', overwritehost, overwrite.cli.url, and trusted_proxies correctly. If these are wrong, the URLs returned by Login Flow v2 (and downloads) can point to the wrong scheme/host and fail. Always use an https:// server URL in the plugin.
• Upload size limits (for chunked upload / large attachments) — raise PHP upload_max_filesize and post_max_size, and the web-server body limit (nginx client_max_body_size, e.g. 0 or a large value). Chunked upload sends small chunks, but the final assembly and very large files still hit these limits.
• Request timeouts — for large vaults or big files, increase PHP max_execution_time and php-fpm / web-server timeouts (e.g. nginx fastcgi_read_timeout). The plugin's own network timeout is configurable in settings.
• Brute-force protection — Nextcloud throttles repeated requests from one IP and can return HTTP 429, especially when several devices sync from the same network or after auth errors. If you hit this, whitelist the network in Administration settings → Security, or set auth.bruteforce.protection.enabled/the IP allow-list in config.php.
• Background jobs (cron) — configure Nextcloud's recommended Cron background-job mode so version cleanup and other maintenance run reliably.
• App passwords & two-factor auth — never use your main account password; if 2FA is enabled an app password is mandatory. Login Flow v2 issues one for you automatically.
• Checksums (optional, recommended) — the plugin prefers Nextcloud's oc:checksums (SHA-256) for change detection and automatically falls back to ETag when they aren't present, so no configuration is required; leaving Nextcloud's default checksum support enabled gives the most accurate detection.

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How it works (in brief)

On connect, the plugin probes /status.php (maintenance mode) and /ocs/v1.php/cloud/capabilities to learn the server version and which features (checksums, files locking, …) are available. It then maintains a per-device state database — a snapshot of every file's path, content hash, and remote file ID at the last successful sync. Each sync diffs the current state against that snapshot and the server's sync-token, transferring only what changed. Every Nextcloud-specific behavior is gated behind capability detection, so the same plugin works against a full Nextcloud Hub and a bare WebDAV server alike (Progressive Enhancement).

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Testing & reliability

Sync correctness is guarded by an extensive automated test suite: hundreds of fast pure-logic tests (run on every change) plus live end-to-end suites that drive two devices against a real Nextcloud server, including exhaustive option-combination matrices for conflict resolution and multi-device convergence.

These tests exist specifically to prevent sync-inconsistency states — data loss, endless re-uploading/re-downloading, a remote change that never reaches the local copy, or a local change that never reaches the remote. Even so, no test suite can cover every possible case, and unintended behavior can never be entirely ruled out. If you ever run into such a situation, please don't hesitate to open an issue — it will be addressed as quickly as possible.

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Privacy & security

• This plugin collects no telemetry whatsoever. No usage data, analytics, or crash reports are gathered or sent anywhere; the only network traffic is the sync between your vault and your own Nextcloud/WebDAV server.
• App passwords / credentials are kept in Obsidian's secret credentials store, never written in plain text to data.json.
• Your main account password is never used or stored — only app passwords (issued manually or via Login Flow v2).
• All network traffic uses Obsidian's requestUrl API.
• The Obsidian config folder (.obsidian/) is excluded from sync by default — only your notes and other vault files are synced. You can opt in to syncing selected parts of it via Sync config folder (see below). Community plugins (.obsidian/plugins/) and the plugin's own sync-state database are never synced, regardless of settings — they hold executable code and device-specific state, which is unsafe to overwrite across devices.

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Limitations

• End-to-end encryption (E2EE) relies on the HTTPS transport layer; the plugin does not add a redundant encryption layer of its own. This is a deliberate trade-off favouring maximum transport security and performance.
• Config folder sync is opt-in and selective. Enable Sync config folder in settings to sync chosen categories of .obsidian/ across devices: Appearance, Themes & snippets, Hotkeys, Core plugin settings, and Bookmarks. Community plugins and the plugin's own sync-state database are never synced (executable code / device-specific state). A synced change to core-plugin settings may require an Obsidian restart on the other device to take effect.
• Designed primarily for Markdown / text Vaults; single files in the hundreds-of-MB range are beyond the v1 design target.
• Keep the Vault on local storage — don't double-manage it with another cloud sync (e.g. iCloud Drive) at the same time.
• Nextcloud-specific features require a compatible server version; older or non-Nextcloud servers transparently fall back to core WebDAV sync.

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Contributing & feedback

Issues and pull requests are welcome on GitHub. The plugin is still maturing, so feedback of any kind is especially valuable:

• 🐛 Report a bug → GitHub Issues
• 🙋‍♂️ Request a feature / share your impressions → GitHub Discussions

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License

MIT © Daisuke ITO