Senior Backend Engineer

Rainfall Ventures; Polska; Hybrid; PLN 335,000 - 580,000; Full time

Benefits offered by this job

Hybrid Warsaw office

Luxmed

Pyszne.pl voucher

Multisport

Monthly Happy Hours

Snacks & Breakfasts

Job summary

Papaya Gaming in Warsaw is seeking an experienced Backend Developer to join the Payments & Fraud team. You will design and build high-scale backend services powering payments, fraud detection, and user transactions for millions of players.

You will work in a fast-paced environment, mentor teammates, and explore new technologies to improve reliability, scalability, and time-to-market. Hybrid work model with a modern office in central Warsaw and competitive B2B terms.

Qualifications

• 6+ years of server-side development experience and architecture.
• Hands-on experience with cloud-based architectures and scalable backend systems.
• Proficiency in Node.js or another major backend language.
• Interest in agentic coding and AI-assisted development tools.
• Passion for learning and adopting new technologies.

Responsibilities

• Develop and maintain a high-scale backend platform serving millions of users.
• Design end-to-end solutions to improve time-to-market and system efficiency.
• Write high-quality, performant, maintainable code following best practices.
• Experiment with new technologies, tools, and third-party frameworks to drive innovation.
• Mentor new team members and contribute to a culture of engineering excellence.

Skills

Server-side

Cloud architecture

Node.js

AI tooling

Learning mindset

Problem solving

Tools

AWS

Kubernetes

TypeScript

Redis

MySQL

Job description

Description

At Papaya, we believe in the power of play. We create skill-based mobile games that combine fun, competition, and real rewards — enjoyed by millions of players worldwide.

We're building a platform where players join tournaments, connect with others, and keep coming back. With a strong focus on innovation, scalability, and user experience, we aim to redefine what mobile gaming can offer.

We’re a fast-growing, profitable company with the spirit of a startup — no corporate bureaucracy, no endless layers of approvals. Everyone on the team makes a real impact on the product, and your voice truly matters.

The Core R&D group is a key part of Papaya Gaming’s Platform division, responsible for developing and maintaining core products that shape the player’s journey. From registration, account management, payments, and restrictions to tournaments and matchmaking, the team ensures a seamless and scalable gaming experience for millions of players worldwide.

We handle payments and fraud prevention across the platform. The team integrates with multiple banking systems, manages secure transactions, and develops fraud detection mechanisms. Supporting millions of players, Typhoon ensures smooth and safe financial operations within Papaya’s ecosystem.

We are looking for an experienced Backend Developer to join our Payments & Fraud team and help build high-scale, mission-critical backend solutions. You will work in a fast-paced, highly technical environment, designing and developing scalable, resilient, and high-performance backend services that power the Payments and Fraud ecosystem.

We offer a hybrid work model with flexibility at our growing Warsaw office.

Responsibilities

• Develop and maintain a high-scale backend platform serving millions of users.
• Design and implement end-to-end solutions that reduce time-to-market and improve system efficiency.
• Write high-quality, performant, and maintainable code following industry best practices.
• Experiment with new technologies, tools, and third-party frameworks to drive innovation.
• Mentor new team members and contribute to a culture of engineering excellence.

Tech Stack

• AWS, Kubernetes, Node.js, TypeScript, Redis, MySQL

Requirements

• 6+ years of experience in server-side development and architecture.
• Hands-on experience in cloud-based architectures and scalable backend systems.
• Proficiency in Node.js or another major backend language.
• Experience or strong interest in agentic coding and AI-assisted development tools.
• Passion for learning and adopting new technologies.
• A can-do approach, problem-solving mindset, and ability to work in a fast-paced environment.

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