Senior Software Engineer - Algo Development About Millennium Millennium is a global, diversified alternative investment firm, founded in 1989. Defined by evolution, innovation and focus, Millennium's mission is to deliver results for our investors. Our people are empowered with both independence and support: the autonomy to pursue ideas with conviction and the backing of a global network committed to collaboration, disciplined risk management and continuous learning. With opportunities to deepen expertise and accelerate development, talent at Millennium is equipped to adapt, evolve and build lasting impact over time. Discover how transformative growth accelerates impact. Meet the Team The Algo Development Technology team is part of Millennium's Information Technology organization. The firm's active, multi-manager business model relies on flexible, scalable technology and advanced proprietary systems, including next-generation analytical and trading capabilities. The team builds the execution algorithms and trading platform that Millennium's portfolio managers use to trade equities and futures globally, working closely with quants and execution traders in a collaborative, global engineering environment. It is a small, senior team where engineers own their work end to end and make extensive use of automation and AI-assisted tooling across development, testing and support. What You'll Do • Build real-time algorithmic trading systems focused on execution optimization. • Develop, support and enhance a Java-based proprietary trading framework, a sequencer-based platform designed to be scalable, replayable and reproducible. • Tune and optimize system performance to support low-latency, high-throughput trading workflows. • Own automated testing for algorithms, including simulation, backtesting, regression suites and replay frameworks. • Partner with the production support team to ensure systems are effectively monitored and supported. • Partner with quants, execution traders and global technology teams, facing off with the business to help define and deliver new features. What You Bring • 7+ years of experience with equities execution systems, ideally buy-side. • Experience developing execution algorithms, including VWAP, TWAP, inline and pairs strategies. • Experience working with matching engines, dark pools and algorithm container frameworks. • Experience implementing automated testing strategies for algorithms, including simulation, backtesting, regression suites and replay frameworks. • Deep understanding of market microstructure, pre-trade risk checks, limit frameworks, regulatory requirements and their impact on execution algorithm performance. • Expert-level Java experience building low-latency, GC-aware, high-throughput distributed systems, with a strong grasp of event-driven architectures and messaging platforms such as Kafka, Solace or similar technologies. • Experience building financing or post-trade systems, working with futures trading platforms, using KDB/Q, or familiarity with AI-based code-generation tools is a plus. • Bachelor's degree in Computer Science or a related field. Salary Range Millennium offers a total compensation package which includes a base salary, discretionary performance bonus, and comprehensive benefits. The estimated base salary range for this position is $175,000 to $250,000, which is specific to New York and may change in the future. When finalizing an offer, we take into consideration an individual’s experience level and the qualifications they bring to the role to formulate a competitive total compensation package.