Mobile App Developer - Remote in United Kingdom

Role Title: Senior Mobile Software Engineer

Role Type: Contractor (~15 hrs a week)

Location: Remote

In this role, you'll apply your expertise to help train next-generation AI systems. Your work will shape how models learn, reason, and perform through high-quality, real-world input.

As an expert, you will create Reinforcement Learning Environments that test an AI model’s ability to solve complex mobile software engineering problems related to fixing code, creating features, refactoring code, and optimizing performance. You will be tasked with creating a reproducible environment and a golden reference solution for each problem.

Scope of Work

• Create realistic, interesting, and extremely challenging mobile coding tasks for frontier AI models using your preferred repositories.
• Design problems that require strong mobile engineering skills, such as tracking down subtle bugs, building non-trivial features, handling application state and lifecycle, or improving performance.
• Develop tasks relevant to your expertise: cross-platform applications using TypeScript, JavaScript, or Dart; iOS applications using Swift; or Android applications using Kotlin.
• For each task, define the problem, build a reproducible environment, and write deterministic verifiers that accept correct solutions across different valid implementations while rejecting incorrect, incomplete, or hard-coded approaches.
• Provide a reference solution showing how the task can be solved.

Preferred Qualifications

• Significant hands-on expertise in at least one of the following mobile development tracks:
• Cross-platform: TypeScript or JavaScript with React Native, or Dart with Flutter.
• iOS: Swift with SwiftUI or UIKit.
• Android: Kotlin with Jetpack Compose or the Android View system.
• Deep understanding of mobile application architecture, state management, asynchronous programming, and application lifecycle.
• Proven ability to debug complex mobile applications, resolve bugs, and deliver effective performance improvements.

Compensation Structure

Compensation is output-based; experts are paid per task that meets the project specifications. The time required to complete work may vary depending on the expert’s experience and workflow. Minimum weekly submission requirements apply and will be communicated during onboarding.

Start Timeline & Availability

• We typically fill roles within