Senior Android Developer (For Independent Contractors)

Details

As part of the Car Hire Insurance & Flexibility Team in Amsterdam, you will expand the reach and impact of two mobile experiences in Booking.com's Android app: Car Hire Insurance, protecting customers when they rent a car, and Flexibility products for Accommodation, giving guests the freedom to change their plans. You will work with Android, iOS, backend engineering, UX design, product, data, and quality teams to create seamless mobile experiences for millions of customers.

Responsibilities

• Build new features end to end, collaborating with Android, iOS, and backend engineers.
• Own technical decisions and lead architectural discussions, supported by RFCs, ADRs, and design documentation.
• Maintain high production quality by monitoring crashes, handling incidents, resolving complex bugs, and leading incident investigations.
• Support the professional growth of colleagues and help onboard new team members.
• Improve owned services by optimizing performance and resource usage.
• Keep insurance products and new features aligned with current technology standards and department guidelines.
• Meet service-level agreements for test coverage and quality through appropriate tests and processes.
• Profile applications to identify bottlenecks, optimize performance, and monitor app health metrics.
• Connect business and product goals to complex technical tasks.
• Prioritize issue resolution based on customer impact.
• Collaborate with app developers, backend developers, product owners, and quality specialists to improve the customer experience.

Requirements

• 6+ years of experience as an Android Developer, with Kotlin as the primary language.
• Strong hands-on experience building production UI with Jetpack Compose.
• Deep understanding of Kotlin Coroutines and Flow, including structured concurrency, cancellation, threading, and testing asynchronous code.
• Experience with modern Android architecture, including MVVM/MVI, Jetpack ViewModel, Navigation, and dependency injection with Hilt or Dagger.
• Extensive experience writing unit, UI, Compose, Espresso, and screenshot tests.
• Strong knowledge of full-stack engineering and backend software concepts.
• Experience designing and evolving API contracts between applications and backend services.
• Experience with multi-module Gradle projects.
• Excellent communication skills, including the ability to communicate with technical and non-technical stakeholders.
• Experience profiling Android applications using Android Studio Profiler, Baseline Profiles, and Macrobenchmark.
• Experience with A/B testing and release planning.
• Fluency in written and spoken English.

Nice to Have

• Experience with GraphQL, including schema design, queries, mutations, and fragments, ideally in a federated setup.
• Experience with Kotlin Multiplatform.
• Experience shipping an application to the Google Play Store.
• Motivation to explore new technologies, applications, and environments.

Contract Details

• Independent contractor position.
• Duration: 1 year, from October 16, 2026, to October 15, 2027.
• Working time: 40 hours per week.
• Pay rate: €60–€130 per hour.

Offered

• The opportunity to contribute to a high-scale, complex, world-renowned product used by millions of travellers.
• A fast-paced and performance-driven culture.
• Opportunities to use technical expertise, leadership capabilities, and entrepreneurial skills.
• The opportunity to promote and drive impactful engineering solutions.
• Technical, behavioural, and interpersonal development through on-the-job opportunities, hackathons, conferences, and community participation.