> For a complete page index of the Captain API documentation, fetch https://docs.captain.dev/llms.txt?excludeSpec=true

# Real-Time Sync Events for Every Provider

* **Real-time events for every sync provider**: [Subscribe Webhook](/reference/sync/manage/webhooks) returns a `queue_arn` for S3 (events travel AWS-natively) and a Captain-hosted `ingest_url` for GCS, R2, Supabase, and Backblaze, so object changes propagate in under a minute. Google Cloud Storage joins the sync providers. See [Set Up Sync](/guides/sync/set-up).

Same day: [Stable Document IDs](/changelog/2026-08-10-stable-document-ids), [Zero-Downtime Overwrites](/changelog/2026-08-10-zero-downtime-overwrites)