API-FIRST ARCHITECTURE FOR MODERN FINTECH PLATFORMS: BEST PRACTICES AND DESIGN PATTERNS

Iyiola Ifeoluwa Johnson; Awogbade Kehinde; Omisope Abiodun Oluwasegun; Asiyanbola Olaoluwa Ebenezer; Samson Precious Loveth

doi:10.5281/zenodo.21501363

Abstract

Application Programming Interfaces (APIs) are becoming the basic protocol between business capabilities,
internal teams and external partners for financial technology (FinTech) platforms. In this article, we take a look
at API-first architecture as a design model for developing scalable, secure and regulatory compliant FinTech
systems. The article highlights how specific architectures – identified from peer-reviewed and industry literature
relating to microservices, open banking and event-driven design – can be used to model and resolve the specific
pressures faced by financial services in terms of regulatory requirements (e.g. PSD2, open banking requirements),
transactional consistency, fraud prevention, and third-party interoperability. Reported outcomes from the
literature have been made synthetical and presented comparatively in the form of a reference architecture diagram
and two summary tables. The talk emphasizes the compromises made between agility and complexity, and
provides some tangible suggestions for engineering organizations that need to implement API-first approaches in
regulated financial settings.

Keywords

API-first architecture; microservices; FinTech; open banking; design patterns; scalability; software engineering

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