Senior Java Developer at ajax

Ajax Systems is a full-cycle company working from idea generation and R&D to mass production and sales. We create security solutions for residential and commercial properties, with a portfolio of 280+ devices across intrusion protection, video surveillance, fire safety, and automation. The whole team is in one office in Lviv, all technical and product decisions are made locally. We’re looking for an Java Developer to join us and continue the evolution of a product that we love: someone who takes pride in their work to ensure that user experience and development quality are superb. You will be able to develop the apps in the best hardware company of Ukraine with around 300M active users around the world. Moreover, very soon you will have a chance to start several new products from scratch. Required skills: • 5+ years of commercial experience in backend development with Java in an enterprise environment; • Strong understanding of Java Concurrency and hands-on experience with concurrent programming in production systems; • Solid understanding of SOA, microservices, and event-driven architecture; • Practical experience with cloud computing platforms; • Experience building and supporting high-load, scalable, and highly available systems; • Hands-on experience with messaging brokers; • Strong understanding of modern backend infrastructure, NoSQL, key-value databases, and in-memory storage solutions; • Practical experience with Docker or Kubernetes; • Experience with Git, Gradle or othet CI/CD tools; • Strong knowledge of unit testing and automated testing approaches. Would be a plus: • Experience with some of technologies: Redis, Netty, Akka, NATS, AWS, MQTT, Kafka, MongoDB, gRPC. • Practical experience with Kotlin. What you will do: • Design and develop core backend services and data pipelines for the product line; • Build clean, maintainable, and production-ready code with a strong focus on quality; • Contribute to backend architecture, drive technical decisions, and document solutions for reliable deployment and operations; • Ensure proper test coverage with unit and integration tests; • Take ownership of performance, scalability, and cost efficiency within your domain; • Maintain production reliability through monitoring, alerting, dashboards, and runbooks; • Investigate and resolve production issues, including deep-dive analysis of complex cases; • Work in a strong engineering culture with testing, continuous delivery, and DevOps practices; • Collaborate closely with product and engineering teams to deliver new features and improve existing services. Why this role is interesting: • Opportunity to work on high-load backend systems and distributed architecture; • Real impact on core product development and architectural decisions; • Modern technology stack and engineering-driven environment; • Close collaboration with experienced engineers in a culture that values quality, ownership, and technical excellence; • Challenging tasks where performance, reliability, and scalability truly matter. We offer: • The opportunity to share and implement your own ideas that could impact products and production; • Work with a motivated team and an environment with a zero-bullshit culture; • Competitive salary; • Medical insurance; • Corporate English classes; • Compensation for professional training; • The chance to take part in beta testing of Ajax security systems — receive and test new devices before their release. Ajax Systems is a Ukrainian success story, a place of incredible strength and energy. Join us in making Made in Ukraine 🇺🇦 synonymous with reliability.