Java integration engineer

Onlyplay is looking for a Java Developer to join our Integrations team.

Our goal is to build reliable and scalable connections with external systems such as gaming platforms, billing services, and real-time data APIs. We develop our own high-performance Java framework based on Netty, with custom service bootstrapping and command-line configuration. In this role, you’ll be at the core of our connectivity layer: building adapters, processing data in real-time, and evolving the infrastructure that links our game platform to the outside world.

Responsibilities:

• Develop and maintain integrations with external partners (game platforms, billing APIs, data providers)
• Build network adapters using our internal Java framework (based on Netty)
• Design and implement protocol parsers (JSON, XML, Protobuf, etc.)
• Collaborate with backend, infrastructure, and QA teams to ensure smooth integrations
• Monitor, debug, and optimize the performance of partner connections
• Document protocols, endpoints, and integration flows
• Participate in code reviews and architecture discussions

Required Skills and Qualifications:

• 3+ years experience
• Prior experience working on partner integrations or similar systems (e.g., gaming platforms, payment providers, analytics APIs, affiliate networks, etc.)
• Strong knowledge of Java 11+, including multithreading and collections
• Experience with Netty, NIO, or any event-driven networking framework
• Solid understanding of HTTP, WebSocket, and UDP protocols
• Experience working with JSON and XML serialization/deserialization
• Familiarity with command-line tools and argument parsing (e.g., Apache Commons CLI)
• Proficient with Git, Docker, Grafana, Postman, Linux-based environments, and logging tools (e.g., Log4j)
• Ability to read and navigate existing codebases without full documentation (yes, we don’t have it yet)

We Offer:

• Remote-first and flexible working hours
• A mature codebase with a custom Java framework (no Spring overhead)
• Real influence on architecture and technical decisions
• Interesting challenges: low-level networking, real-time data, partner protocols
• Small agile team without bureaucracy
• Competitive compensation (based on skills and experience)
• Opportunity to grow inside a fast-evolving company in the gaming industry

Now we are looking for a new teammate to help us conquer new horizons. If you dream of something really extraordinary, then we are on the same path. We really hope that we will have a match!