Reference Agency - Kotlin Back-End Developer

Back-End Developer is needed in Egypt.

Client: Reference Agency

Location: Cairo, GZ, eg

Contract: Part-time

Job Description

Our Client is a fast-growing HealthTech company building the Arab world’s first unified health-data platform — one Arabic-first dashboard that brings together users’ sleep, nutrition, activity and heart data from 15+ smart devices, powered by an AI health assistant.

We’re looking for a hands-on Back-End Developer to work part-time and fully remote on the core services that ingest, process and serve millions of health-data points. You’ll own backend features end-to-end in a modern Kotlin + Spring Boot stack, working closely with the mobile team on clean, well-documented APIs.

Key Responsibilities

• Design, build and maintain backend services in Kotlin 2.x and Spring Boot 3.x
• Model and optimize data across PostgreSQL 17 (transactional) and ClickHouse (analytics/OLAP)
• Build and document clean, versioned REST APIs consumed by the iOS and Android apps
• Integrate and normalize data from third-party wearable/device APIs
• Design efficient data flows between the transactional store and the analytics layer
• Ensure security, encryption and privacy standards for sensitive health data
• Write tests, participate in code reviews, and keep technical documentation current

Requirements

• Proven experience shipping production backend systems in Kotlin
• Strong hands-on Spring Boot 3.x experience
• Solid PostgreSQL skills (schema design, indexing, query optimization)
• Working experience with ClickHouse or a comparable OLAP/columnar store
• Comfortable designing REST APIs and working with JSON at scale
• Self-directed and reliable in a remote, part-time setup
• Good written English; Arabic is a plus

Skills

• Kotlin · Spring Boot · REST API design · PostgreSQL · ClickHouse
• Coroutines/concurrency · Gradle · Docker · CI/CD · Git
• Data modeling · performance tuning · secure data handling

Benefits

• 100% remote, flexible part-time hours
• Modern greenfield stack with real ownership
• High-impact product in a fast-scaling regional HealthTech