Fiftify: WMS integration with BAS, the Ukrainian ERP

Fiftify customers in Ukraine keep their books in BAS KUP, the local ERP standard. Every receipt was entered twice: once by the warehouse team in Fiftify, then re-typed by accounting into BAS. Stock in the books trailed the floor by a day or more, mismatches were reconciled by hand at month close, and documents went missing between the two systems. What they needed was a single exchange channel with unambiguous ownership for every entity, so neither system could overwrite the other.

We built the exchange on the BAS KUP HTTP services. On the ERP side we exposed services for items, prices, counterparties, orders and stock documents; on the Fiftify side we shipped a NestJS connector with a BullMQ queue on Redis. Data ownership is explicit: items, price types and counterparties originate in BAS and are read-only inside Fiftify, while physical stock and movements are born on the warehouse floor, so BAS receives them as already posted receipt and write-off documents. Every document carries a GUID, so redelivery never creates duplicates. Items are matched by code and barcode, with units of measure and packaging handled separately so a six-pack never lands in the books as six units. Customer orders from Shopify enter BAS through the same channel. Each night the connector runs a full stock reconciliation and reports any drift to accounting.