Building integrations in-house presents complex technical challenges that multiply as fintech startups scale. API fragmentation creates immediate obstacles; for example, QuickBooks uses OAuth 2.0 while NetSuite demands token-based authentication. Xero returns dates in ISO 8601 format while competitors use Unix timestamps. These differences compound into major engineering efforts.
Financial logic varies dramatically across platforms. A straightforward invoice in one system becomes a complex multi-object transaction in another. Multi-entity consolidation, foreign exchange calculations, and revenue recognition rules all follow platform-specific implementations.
A properly built integration typically requires 2-3 months of focused engineering effort. Supporting five platforms means 10-15 months of development before achieving basic market coverage. Once deployed, maintenance consumes 20-30% of initial development time annually. Compliance requirements add another layer, as financial data demands audit trails, adherence to ASC 606 and IFRS 15, and careful attention to data residency regulations.
Integration platforms address these challenges by abstracting differences behind consistent interfaces, compressing timelines from months to weeks while standardizing data models across systems.