Who are we?

Papaya Stars is the latest innovation from Papaya, a groundbreaking subsidiary launched to redefine the intersection of social platforms and gaming. Imagine Instagram, Roblox, and TikTok Challenges rolled into one – that’s the revolution we’re building.

Our mission? Empower creators and players with advanced tools and an immersive platform that’s fun, engaging, and cutting-edge.

The role:

We’re looking for a Senior Full-Stack Engineer who thrives in fast-paced, experimental environments. You’ll be the kind of builder who loves turning ideas into end-to-end features - from concept to deployment - combining React Native on the client side with a .NET-based backend.

This role is backend-oriented but requires strong full-stack ownership, helping us design, develop, and launch monetization-focused and experimental features that drive engagement and growth.

• Design, build, and maintain scalable mobile features using React Native and .NET Core.
• Take features end-to-end - from ideation and prototyping to production rollout and performance optimization.
• Collaborate closely with Product, Design, and Data teams to experiment rapidly, test hypotheses, and improve market fit.
• Implement and iterate on monetization-related functionalities, in-app experiences, and growth-driven mechanics.
• Debug complex technical issues across the stack and improve performance and reliability.
• Contribute to architecture decisions, code reviews, and mentoring as the team grows.

• 4+ years of experience in software development, with hands-on full-stack experience (React or React Native + .NET Core).
• Proven experience building consumer-facing features (B2C, gaming, e-commerce, or social platforms preferred).
• Strong understanding of API design, backend architecture, and cloud environments.
• Practical experience with mobile development (React Native or native mobile).
• Comfort with rapid prototyping, working iteratively, and adapting to changing priorities.
• Ability to handle both feature implementation and DevOps/infrastructure tasks when needed.
• Excellent problem-solving, debugging, and communication skills.

Nice to have:

• Experience with machine learning algorithms or recommendation systems.
• Experience with GraphQL.
• Familiarity with feature flagging, experimentation frameworks, or A/B testing.

What we offer:

• Join a profitable company with the heart of a startup – stable, growing, and full of energy.
• Enjoy a hybrid work model with flexibility and a growing Warsaw office.
• Receive competitive compensation tailored to the Polish market - B2B Service agreement
• Comfortable office in central Warsaw equipped with all the necessary tools to conquer the universe
• Luxmed Medical services
• Monthly 'Pyszne.pl' voucher
• Multisport card
• Monthly Happy Hours
• Snacks and Breakfasts