Cosmos change feed

Pick the change feed mode

Latest version mode is the default. It exposes inserts and updates, keeps only the latest visible version, and does not capture deletes. All versions and deletes mode captures every change, including deletes, but needs continuous backup and has different client support.

Choose how Python consumes it

Python can use the pull model with continuation tokens or an Azure Functions Cosmos DB trigger. The change feed processor library itself is available for .NET and Java.

changes = container.query_items_change_feed(start_time="Beginning")
for item in changes:
    handle(item)

Save the continuation token so a restarted pull consumer resumes from the same position.

Separate independent consumers

A processor or Functions trigger stores progress in leases. Instances with the same logical lease identity split the work. Give independent consumers different processor names, lease prefixes, or lease containers when each must see every change.

Design for retries

Delivery is at least once. Make handlers idempotent and catch item-level failures so one malformed item does not keep the same batch from checkpointing.