We’re syncing 50,000+ contacts from our marketing automation platform to Zendesk Sell using the Integration Hub API, but we keep hitting rate limit errors that cause incomplete data syncs. The sync starts fine but after about 15 minutes we get 429 responses and the process fails.
Error we’re seeing:
HTTP 429 Too Many Requests
Retry-After: 3600
X-Rate-Limit-Remaining: 0
We’re batching requests at 100 records per call, but apparently that’s still too aggressive for the API rate limits. The documentation mentions rate limits but doesn’t provide clear guidance on optimal batch sizes or request timing for bulk operations. We need to complete these syncs within our nightly maintenance window but can’t afford to wait an hour between retries. What’s the recommended approach for bulk contact syncing that respects rate limits while maintaining reasonable performance?
Batch size of 100 might be part of your problem. Each batch request counts against rate limits differently than individual requests. Try reducing to 50 records per batch and add a small delay between batches. We use 25 records per batch with 500ms delays and rarely hit limits even with large syncs.
You need to implement exponential backoff and respect the Retry-After header. When you get a 429, don’t just fail - wait the specified time and retry. Also, monitor the X-Rate-Limit-Remaining header on successful requests to slow down before hitting the limit. We throttle our sync speed dynamically based on remaining quota.
The Integration Hub has different rate limit tiers depending on your Zendesk Sell plan level. Enterprise plans get higher limits than Professional. Check what tier you’re on and whether you can request a rate limit increase for your use case. We had similar issues and got our limits raised after explaining our bulk sync requirements to support.