When evaluating sync tools, one of the most important questions to ask is: how does it detect changes? The answer has a huge impact on how quickly your stores stay in sync.
How polling works
Polling tools check for changes on a schedule — every 5 minutes, every 15 minutes, or hourly. They compare the current state against a stored snapshot and sync any differences. This works, but it means your stores can be out of sync for up to the polling interval.
How webhooks work
Shopify fires a webhook the moment something changes — a product is created, updated, or deleted; an order is paid; inventory changes. MultiStore Sync registers for these webhooks and processes them in real time. The average sync time is under 500ms.
Why this matters
For inventory, the difference is critical. If you're running a flash sale and selling 100 units in 10 minutes, a polling-based tool might not catch inventory changes fast enough. Overselling becomes a real risk.
Webhook reliability
Shopify retries failed webhook deliveries up to 19 times over 48 hours. MultiStore Sync acknowledges webhooks immediately (returning a 200 status) and processes them asynchronously, so retries are rare.
The trade-off
Webhooks require a publicly accessible endpoint and proper HMAC verification. MultiStore Sync handles all of this — you don't need to configure anything. But it's worth understanding why webhook-driven sync is fundamentally more reliable than polling for high-volume stores.