Sync

Sync is the CDA endpoint that synchronizes a Space's published material incrementally (as deltas). Instead of re-fetching all published Content, Media, and Content Type every time, a client fetches everything once and caches it locally, then from that point on receives only what has changed and what has been deleted since the last sync and updates that cache. Apps that need to hold the entire published material (offline caches, search indexes, static site builds, and so on) use it to reduce the amount of data transferred.

Synchronization runs in two phases. First you fetch everything with an initial sync and save the nextSyncUrl carried in the response. From then on you call a delta sync with the sync-token contained in that URL to receive only the changes and deletions, and because the response again gives you a new nextSyncUrl, you save that value and repeat.

Sync flow

1. Initial sync: Call with ?initial=true&type=All to fetch all published material. A nextSyncUrl is carried at the end of the response.
2. Save nextSyncUrl: Save the received nextSyncUrl value as is. This URL contains the sync-token to use on the next call.
3. Delta sync: Call again with the sync-token from the saved nextSyncUrl. Only what has changed and what has been deleted since the last sync is carried in the response, along with a new nextSyncUrl at the end.
4. Repeat: Save the new nextSyncUrl you received, and repeat step 3 whenever you need to sync.

sync-token is not a value you create yourself but an opaque cursor. Do not interpret its format or assemble it by hand; pass the value you received from the previous response's nextSyncUrl to the next call as is.

Response structure

The following is the initial sync (type=All) response of the demo Space. items carries published entities and deletion markers mixed together, and at the end comes the nextSyncUrl to use for the next delta sync.

{
  "sys": { "type": "PageResponse" },
  "limit": 15,
  "items": [
    {
      "sys": {
        "id": "3trmXRM3RqbgSnifyg7PBUM8Ds0Xvw",
        "type": "Content",
        "space": { "sys": { "id": "tcq4V2Xb", "type": "Refer", "targetType": "Space" } },
        "contentType": { "sys": { "id": "3trmXRM3RqbgSnifyg7PAmlxvX4fGY", "type": "Refer", "targetType": "ContentType" } },
        "createdAt": "2026-06-17T16:58:56.660Z",
        "updatedAt": "2026-06-18T01:46:55.604Z",
        "revision": 3
      },
      "fields": {
        "price": { "en-US": 18000 },
        "description": { "en-US": "Double-wall vacuum insulation keeps drinks hot or cold for hours. A roomy 500ml." },
        "photo": {},
        "productName": { "en-US": "Stainless Tumbler 500ml" }
      }
    }
  ],
  "links": {},
  "nextSyncUrl": "/v1/spaces/tcq4V2Xb/sync?sync-token=165rWhDiuLNoYOwjVQQAYXMA7makztXnhAV3qamYU75jFldqtvaEhMnr29PqsKTAbcspOP6ziWrv2CuIaa450zqOtXNXBUwvoSl6VV7PzwI0SXaSv504321hl3hE7MoebljTlKeltN8fYIFldu1TPdfeIoqLtN"
}

Key properties:

• sys.type: The kind of the envelope wrapping the sync response. It is always "PageResponse".
• limit: The number of items carried at once.
• items: An array into which published entities and deletion markers go mixed together. The first item in the example above is a live Content (with its body), and a deletion marker (DeletedContent) carries only sys without a body. Item kinds are covered in Item kinds below.
• links: The page links object. Because Sync chains the next page and next delta through nextSyncUrl, this object can be empty.
• nextSyncUrl: The path to call for the next delta sync. Use the sync-token of this URL on the next call as is.

The fields of an items entry come as the locale map, not resolved by locale. As with productName being { "en-US": "Stainless Tumbler 500ml" } in the example above, each field value comes as a map holding per-locale values. Unlike CDA Content and CDA Media reads, which pick a single value with the locale parameter, Sync sends down the full map without resolving the locale. The client receives this map, caches it locally, and resolves it when needed. That is why Sync has no locale parameter.

photo being {} (an empty map) in the example above is because there is no linked Media in any locale.

Item kinds

items carries items with differing sys.type mixed together. Broadly there are two branches: live entities and deletion markers.

A deletion marker is a signal that the resource is no longer in the published material. The client looks at the marker's sys.id and removes that item from the local cache.

In an initial sync, the type parameter selects what to receive.

When type is Content or DeletedContent, you can narrow to only the items belonging to a specific Content Type with the content-type parameter.

API

The base URL for the two endpoints below is https://cda.weegloo.com/v1, and a Bearer token that authenticates against CDA is required in the Authorization header. Both use the same path GET /spaces/{spaceId}/sync, and query parameters distinguish initial sync from delta sync. Unlike Content and Media reads, Sync has no locale parameter. Values come as the locale map.

An empty items means there have been no changes since the last sync. A new nextSyncUrl still comes in this case, so save that value and use it as is on the next sync.

Related documents

• CDA overview: CDA as a whole and its common delivery behavior.
• CDA Content: Reading a single locale-resolved published Content.
• CDA Locale: The Locale list used when resolving the locale maps received via sync.
• Localization (concept): Resolving locale values and fallback.