Mid Backend Developer (Firebase) - Part-time - APAC/EMEA

This is a senior, backend-weighted engineering position supporting a live, revenue-generating mobile application with a substantial existing user base on iOS and Android.

The role is approximately 80% backend infrastructure and 20% Flutter client work, structured as an ongoing part-time contract with significant ownership over technical decisions within the backend domain.

• Firebase Backend Development Proven, hands-on experience designing and operating Firebase backends that support real users at scale. This includes Firestore, Cloud Functions, security rules, indexing strategy, and a working understanding of the platform’s cost model sufficient to keep it under control as usage grows.
• Data Modelling Demonstrated expertise in Firestore data modelling, including direct experience redesigning a schema that did not hold up under growth. Candidates should be able to speak concretely about trade-offs in read/write patterns and cost per operation.
• Production Data Migrations Experience planning and executing migrations against live production databases without downtime or data loss, including dry runs, verification steps, and a clear rollback plan.
• Operational Experience Experience supporting a live application with a real user base, including firsthand experience managing the downstream impact of production issues.
• AI-Assisted Development Experience operating multiple AI coding agents in parallel, paired with a rigorous and repeatable process for reviewing and validating their output before it reaches production. This is a requirement for the role, not a preference.
• Ownership & Autonomy Comfort taking full ownership of a technical domain within a small team, and the ability to work effectively from desired outcomes rather than detailed specifications., * Experience with in-app subscriptions (RevenueCat, StoreKit, Play Billing), push notifications at scale, hosted search, BigQuery or analytics pipelines, and Google Cloud Platform services beyond Firebase.
• Flutter Development Ability to write and ship production-quality Flutter code independently, without close supervision.

ORYX LOOP Studio is an up-and-coming mobile app development studio. Our founder previously worked with an award-winning app development agency, contributing to the delivery of multiple applications - including one that grew to over 50,000 users. We are now applying that experience to our own portfolio of products.