Fintech Engineering Handbook

▤ Summary

This handbook lays out core engineering patterns for building fintech systems that handle money safely and audibly. It covers precision, rounding, currency handling, ledger design, reconciliation, idempotency, resumable flows, and external API integration. It also explains control frameworks such as audit trails, access control, segregation of duties, and testing practices. The appendix ties these ideas together with practical end-to-end examples for withdrawals, card deposits, and in-app conversions.

▦ Linked Companies

Modern Treasury

$10M to $25M