Subscribe to Salesforce Change Data Capture events for a custom object using the CometD streaming interface to detect record inserts, updates, deletes, and undeletes

In-depth guide

Steps

1. Enable Change Data Capture for the target custom object in Setup under Integrations > Change Data Capture and move the object to the Selected Entities list
2. Authenticate to Salesforce using OAuth to obtain an access token and instance URL for the CometD endpoint
3. Connect a CometD client to https://<instance>.salesforce.com/cometd/<API-version>/ using the access token as the Authorization header value during the handshake
4. Subscribe to the CDC channel /data/ObjectName__ChangeEvent (custom objects) or /data/ChangeEvents (all enabled objects) specifying a replayId of -1 for new events
5. Parse incoming Avro-encoded or JSON payloads; the payload contains a header with changeType (CREATE, UPDATE, DELETE, UNDELETE), changedFields list, and the record fields
6. Store the last processed replayId durably so your subscriber can resume from the correct position after a restart without missing events within the 3-day retention window