Senior Software Development Engineer (Java)

At Halcyon Labs , we build a high-performance real-time data platform used in mission-critical systems across industries such as finance, e-commerce and telecoms. Our platform enables applications to access and process data in milliseconds, powering use cases like fraud detection, real-time inventory tracking and dynamic pricing. We’re looking for a senior Java software development engineer to join the Core team, the group responsible for the engine at the heart of the Halcyon Labs Platform. This distributed, Java-based system combines low-latency data storage, in-place compute and stream processing across clusters of machines. This role is ideal for engineers who enjoy building core backend systems and working on the mechanics of distributed platforms, such as concurrency, coordination, data distribution and behaviour under load, failure and changing cluster topology. WHAT YOU’LL DO Build the runtime engineDesign, implement and evolve core components of the Halcyon Labs runtime, including cluster services, distributed data structures and execution engines. Work on distributed systems problemsContribute to mechanisms for partitioning, replication, coordination and recovery in a distributed cluster. Develop production systemsWrite clean, well-tested Java code for long-running clustered systems that must remain reliable, observable and predictable in production. Contribute to architecture Collaborate with experienced engineers and architects to shape the design and evolution of the platform’s core runtime. Raise the Engineering Bar Participate in design discussions, code reviews and mentoring to maintain the high standards of the Core team. WHAT YOU HAVE You’re a strong Java engineer who enjoys building complex backend systems and understanding how they behave in production. Must have Strong proficiency in Java and the JVM ecosystem Experience building backend platforms or complex systems Solid understanding of concurrency and multithreaded programming Experience designing reliable system components and APIs Ability to debug and reason about complex production systems Nice to have Experience with distributed data systems, messaging systems or databases Familiarity with replication, partitioning or distributed coordination Experience with networking, serialization or storage internals Experience profiling and optimizing latency-sensitive code paths Contributions to open-source systems or developer platforms BENEFITS 25 days annual leave + Bank holidays Group Company Pension Plan Private Medical Insurance Private Dental Insurance Life Insurance EAP (Employee Assistance Program) Originally posted on Himalayas