Fintech payments API platform

Secure REST and microservice APIs for payments and e-commerce, built and led with a team of five engineers.

01 — The problem

Merchants and partners needed one dependable way to take payments, check status and reconcile, while the old monolith made every change slow and risky.

02 — What I built

✦Domain-driven split of the monolith into independently deployable services
✦Versioned REST APIs with authentication, rate limiting and OpenAPI docs
✦Dependency injection and clean layering for testable code
✦Database migration from Oracle to MySQL and SQL Server without downtime

03 — What changed

Faster releases, fewer incidents, and an API partners could integrate with on their own. Client names stay confidential.

04 — Tools

JavaGroovy / GrailsMicroservicesRESTMySQLSQL ServerDocker

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