CountProof keeps your stock and orders perfectly in sync between Shopify, eBay and Amazon — in real time, at a flat price, with every count change explained. Because one oversold order is an angry customer; three is a suspended seller account.
These are real reviews of the most-installed marketplace sync apps, from this year:
“Inventory synchronization between Shopify and eBay is not functioning reliably… This creates a significant risk of overselling. Multiple support requests, no resolution timeline.”
1★ review — Shopify's own sync app, May 2026“Amazon just stopped syncing and I could not get it fixed… every 3 months they update their software and overwrite my customisations.”
1★ review — leading sync app, Jan 2026“Over 300 SKUs… keeping track of stock across multiple sales channels has become a nightmare. I've oversold products.”
Shopify Community, 2025Shopify first, then eBay and Amazon. No CSV files, no field mapping homework — sensible defaults, tweak only if you want.
A sale anywhere updates every channel in seconds — not on a 30–60 minute polling cycle. Marketplace orders flow into Shopify so you pack from one screen.
Every count change is logged: what changed, where, why, when. When a number looks odd, the answer is one click away — not a support ticket away.
The others are black boxes — when counts drift, you can't tell why. CountProof shows its work on every single unit.
Webhook-first architecture. The moment something sells, every other channel knows — during BFCM too.
The “reliable” incumbent triples its price as you grow. CountProof is one flat price. Sell more, pay the same.
Public status page, and support answered by the founder in writing — with your sync log already in hand.
CountProof launches first for Shopify ↔ eBay, with Amazon next. The first 25 founding merchants lock in:
→ $29/mo flat, locked for life (planned pricing)
→ free white-glove migration off your current app
→ a direct written line to the founder