# Sync

This section documents the **sync provider modules** under `sync/`.

They are the low-level engine used by the [Orchestrator](/blueprint-architecture/orchestrator.md).

{% tabs %}
{% tab title="End users" %}
{% hint style="info" %}
If you want setup steps, use [Syncing](/getting-started/first-time-setup/what-do-you-need/syncing.md) and [Configure Pairs](/crosswatch/configure-pairs.md).
{% endhint %}

### What a “sync module” is

Each module exposes the same surface:

* `health()`
* `build_index(feature)`
* `add(feature, items)`
* `remove(feature, items)`

The orchestrator uses those to:

1. Build snapshots.
2. Diff snapshots.
3. Apply writes.

### Modules (in this section)

Open a module page when you’re debugging provider behavior or reading code paths.

Media servers:

* [\_mod\_PLEX](/blueprint-architecture/sync/_mod_plex.md)
* [\_mod\_JELLYFIN](/blueprint-architecture/sync/_mod_jellyfin.md)
* [\_mod\_EMBY](/blueprint-architecture/sync/_mod_emby.md)

Trackers:

* [\_mod\_TRAKT](/blueprint-architecture/sync/_mod_trakt.md)
* [\_mod\_SIMKL](/blueprint-architecture/sync/_mod_simkl.md)
* [\_mod\_MDBLIST](/blueprint-architecture/sync/_mod_mdblist.md)
* [\_mod\_ANILIST](/blueprint-architecture/sync/_mod_anilist.md)

Other:

* [\_mod\_TMDB](/blueprint-architecture/sync/_mod_tmdb.md) (TMDb account sync)
* [\_mod\_TAUTULLI](/blueprint-architecture/sync/_mod_tautulli.md) (history import)
* [\_mod\_CROSSWATCH](/blueprint-architecture/sync/_mod_crosswatch.md) (local backup)

### Related topics

* Feature semantics: [Engine-level features](/blueprint-architecture/sync/engine-level-features.md)
* Orchestrator internals: [Orchestrator](/blueprint-architecture/orchestrator.md)
  {% endtab %}

{% tab title="Power users" %}

### Code map

* `sync/_mod_*.py`
* `providers/<provider>/_watchlist.py`, `_history.py`, `_ratings.py` (feature implementations)

### How to read these module pages

Each `_mod_*` page documents:

* entry point (`sync/_mod_*.py`)
* feature submodules per provider
* capabilities (bidirectional, provides IDs, index semantics)
* state/shadow/unresolved files (when present)
* config namespaces and common keys

### Related blueprint docs

* Planning and applying: [One-way sync](/blueprint-architecture/orchestrator/one-way-sync.md), [Two-way sync](/blueprint-architecture/orchestrator/two-way-sync.md)
* Snapshot rules: [Snapshots](/blueprint-architecture/orchestrator/snapshots.md)
* Provider contract: [Provider contract](/blueprint-architecture/orchestrator/provider-contract.md)
* Real-world quirks: [Provider specifics](/blueprint-architecture/orchestrator/provider-specifics.md)
  {% endtab %}
  {% endtabs %}


---

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