01Case Study

Halcyon — FinTech API

backend / integrations

Designed and built a financial data aggregation API that connects with multiple banking providers, Stripe, and accounting platforms. The API serves as the backbone for a fintech startup's dashboard and reporting features.

Built with GraphQL for flexible querying, queued workers for reliable data sync, and comprehensive monitoring from day one.

Results

  • Aggregates data from 15+ financial providers within seconds
  • Sub-200ms p95 response times on complex GraphQL queries
  • Zero data-loss incidents across 2M+ transactions processed
  • Automated reconciliation runs nightly with alerting