Backend Engineer — Java

Kolomoni Microfinance Institution (Gambia) is a CBG-licensed microfinance institution serving customers across The Gambia. We are recruiting a Backend Engineer to build and maintain the services our products run on.

THE ROLE

You will design, develop, test, deploy and maintain secure, scalable backend applications — the business logic, APIs, integrations and data processing behind our customer-facing products. The work is judged on what survives production: correctness under load, safety under failure, and code the next engineer can maintain. You will report to the Chief Technology Officer.

WHAT YOU WILL DO

• Design and develop secure, scalable, maintainable APIs and application business logic in Java.

• Design database structures and data-access components, and optimise application and database interactions.

• Apply transaction and concurrency management, and idempotency where an operation must not run twice.

• Build applications that handle retries, duplicate requests and partial failures safely.

• Implement authentication, authorisation and application-security controls, and protect sensitive data in transit, at rest and in logs.

• Develop logging, monitoring and audit capability sufficient to reconstruct an incident.

• Write and maintain automated tests, participate in peer review, and resolve production defects.

Requirements

WHAT WE ARE LOOKING FOR

• Substantial hands-on experience building and maintaining production backend services in Java.

• Spring Boot or an equivalent framework, relational databases and SQL, and REST API design.

• Understanding of asynchronous and event-driven architecture, caching, and application security.

• Git, automated testing, containerisation and modern deployment.

• A first degree in computer science, engineering or a related discipline, or demonstrable equivalent experience.

• Experience in financial services or payments — where correctness under failure matters more than speed of delivery — is an advantage.