Senior Full-stack Engineer

1 Hour ago • 4 Years +

Full Stack Development

Job Description

Papaya Stars, a subsidiary of Papaya, is building a revolutionary social gaming platform combining elements of Instagram, Roblox, and TikTok Challenges. The company aims to empower creators and players with advanced tools and an immersive, engaging platform. They are seeking a Senior Full-Stack Engineer to thrive in a fast-paced, experimental environment, turning ideas into end-to-end features using React Native for the client side and a .NET-based backend. This backend-oriented role requires strong full-stack ownership to design, develop, and launch monetization-focused and experimental features driving engagement and growth.

Good To Have:

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

Must Have:

Design, build, and maintain scalable mobile features using React Native and .NET Core.
Take features end-to-end from ideation to production rollout.
Collaborate with Product, Design, and Data teams for rapid experimentation.
Implement and iterate on monetization-related functionalities.
Debug complex technical issues and improve performance.
Contribute to architecture decisions and code reviews.
4+ years of full-stack experience (React/React Native + .NET Core).
Proven experience building consumer-facing features.
Strong understanding of API design, backend architecture, and cloud environments.
Practical experience with mobile development.
Ability to handle feature implementation and DevOps/infrastructure tasks.

Perks:

Join a profitable company with the heart of a startup.
Hybrid work model with flexibility and a growing Warsaw office.
Competitive compensation tailored to the Polish market - B2B Service agreement.
Comfortable office in central Warsaw equipped with all necessary tools.
Luxmed Medical services.
Monthly 'Pyszne.pl' voucher.
Multisport card.
Monthly Happy Hours.
Snacks and Breakfasts.

Add these skills to join the top 1% applicants for this job

communication

problem-solving

game-texts

alphabeta-testing

react

prototyping

.net-core

graphql

algorithms

react-native

machine-learning

Description

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.

Responsibilities

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.

Requirements

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