X-FLOW is a mobile game development company established in 2018. We gained recognition after the release of Happy Color, the most popular digital coloring book and one of the most successful ad-driven mobile apps in the world. We take pride in our diverse and talented team and partners, spread across the UK, Cyprus, the Netherlands, and other regions worldwide.

Happy Color is the largest mobile application in its category, with tens of millions of monthly active users. We are developing a live product with a massive audience, high technical load, and a substantial UI footprint.

We’re looking for a strong Unity developer who is confident working with UI-heavy client-server applications and wants to influence product quality and architecture.

What You Will Do:

• Develop and improve client-side features.
• Collaborate with Backend, Design, QA, Analytics, and Marketing teams.
• Integrate and update third-party SDKs (ads, analytics, social).
• Investigate and resolve crashes, ANRs, and performance issues.
• Maintain build stability, asset cleanliness, and UI quality.
• Participate in designing and improving the client’s technical architecture.

Why This Role Is Interesting:

• A product used by millions of people every day.
• Real technical challenges: low-end optimization, large server-driven content catalogs, CDN pipelines, and async resource loading.
• A chance to influence client architecture - we value engineering insight and initiative.
• A low-bureaucracy environment with quick decision-making and respect for developers.
• A mature project that continues to grow and deliver stable results.

Requirements (Must-Have):