How One Team Fixed Data Inconsistency by Centralising Reference Data into One Service

A distributed system architecture split balance-related data across three separate services, each with its own database and read patterns. All three services relied on the same reference data — including account types, statuses, and product attributes — but maintained independent local copies. Over time, this led to semantic inconsistencies where the same account appeared under different categories or interpretations depending on which service was queried. Users noticed conflicting information across screens, while engineers faced incidents, manual reconciliation, and eroding trust in the data. The team ultimately concluded that shared business semantics require a single authoritative source, prompting a move toward a dedicated reference data service.