Syncsafe keeps inventory in sync between two Shopify stores, one way, matched by SKU. What makes it different is what it refuses to do. Every stock change goes through a validation gate before anything is written: it checks the SKU resolves to exactly one variant in the other store, that the result is not negative, and that the change is not big enough to look like a mistake. Anything that fails is recorded and held, not written — and the app names the check that refused it.

• Every stock change is checked before anything is written to the other store
• Refuses writes that would zero or wreck your stock, and tells you why
• Matches variants by SKU, and flags duplicates instead of guessing
• A permanent record of every stock change and why it was or was not written
• Fix a mapping and resync — nothing is lost while it is blocked