Sarcouncil Journal of Engineering and Computer Sciences

Abstract: Financial organizations are using cloud-native API designs more and more to meet evolving customer demands while maintaining demanding safety and regulatory standards. This transformation helps banks, fintech firms, and insurers improve their operational scalability and resilience through the use of serverless computer models, microservices, and containerization. Hardware security module integration, API gateway security, and OAuth2 authentication, among other levels of security methods to safeguard sensitive transaction data, are used in contemporary financial service APIs. Strong consent management and audit capabilities are required in open banking systems where third-party integrations exist; hence, regulatory frameworks such as PCI DSS, GDPR, and PSD2 drive architectural choices. Real-time behavioral analysis and AI-driven automated decision-making systems change fraud detection at the API level. These technical innovations demonstrate how financial institutions may achieve operational excellence by means of wise API integration, balancing innovation with legal compliance and security demands in an ever more digital financial environment.