Illustrative example: real-time inventory sync across 40 seller feeds with signed webhooks

Illustrative example. This is a composite scenario written to show how AACSearch can be used. It does not describe a named customer, and the figures are illustrative, not measured results.

The problem

Forty sellers, forty independent update cadences: some push a fresh feed nightly, a few poll an ERP every few minutes, one still emails a spreadsheet. The marketplace's nightly batch reconciliation job meant a product could show "in stock" for most of a day after a seller actually sold out — shoppers ordered it anyway, and the marketplace absorbed the cancellation and the support ticket.

The move to event-driven sync

Sellers with a real-time feed push stock and price changes straight into the shared collection through the custom push API, each write carrying an Idempotency-Key derived from the seller's own change-event id — so a seller's retry logic (their own network hiccups, their own redeploys) can never double-apply a stock delta on the marketplace's side. Sellers without a real-time integration keep their existing scheduled feed, now pulled hourly instead of nightly.

On the way out, the marketplace subscribed its own inventory service to AACSearch's webhooks: the moment a document's in_stock field flips through an update, a signed webhook fires, verified by HMAC before the inventory service trusts it, and the marketplace's own "sold out" banner and email-alert system react within the same request cycle instead of waiting for the next batch job.

What could change (illustrative figures)

• Propagation time: 24h → under a minute (illustrative) for sellers on the real-time path; the remaining nightly-feed sellers stay on an hourly cycle, a smaller but still real improvement over the previous full-day batch.
• Duplicate-write incidents: zero since cutover (illustrative). The idempotency key absorbed several seller-side retry storms during the migration itself without a single double-applied stock change.
• Out-of-stock orders: −31% (illustrative), measured as orders subsequently cancelled for lack of stock against the pre-migration baseline.

Why it matters

Nothing about the underlying catalogue schema changed — stock is still a facetable field on the same collection. What changed is the path a stock update takes to get there, and the guarantee that a retried update can never apply twice. The webhook side closes the loop: the marketplace's own systems no longer poll AACSearch to find out what already happened.