Software Developer (Platform Engineering) in London

At Hudson River Trading (HRT) the Applied AI team's mission is to increase the speed and quality of work across the firm's most consequential workflows. We build AI systems that help researchers and developers iterate faster, automate increasingly complex work, and enable autonomous exploration at a scale that would not otherwise be possible. We apply frontier models and agentic systems to how quantitative research, software development, and other critical work at HRT gets done. We combine cutting-edge commercial and open-source models and tools with infrastructure, research, and systems of our own. Our work spans the full stack required to make this successful: AI infrastructure, research engineering, post-training and reinforcement learning, agent evaluation, security and alignment, and deployment into real workflows. ResponsibilitiesBuilding scalable infrastructure for training, evaluating, and operating language models and AI agentsDeveloping research environments, evaluation systems, and experimentation platforms that allow us to measure and improve agent performanceImproving model and agent capabilities through post-training, reinforcement learning, prompting, tool design, and workflow optimizationDesigning sandboxing, policy enforcement, monitoring, and other safeguards for increasingly capable autonomous systemsPartnering with teams across HRT to identify work AI can newly perform, develop effective solutions, and turn successful experiments into durable systemsEvaluating new models, techniques, and products, and making informed decisions about when to build, buy, or adapt themSharing technical knowledge and establishing effective practices for building and working with AI across HRTProfileYou are an excellent engineer who can turn ambiguous problems into working systemsYou learn unfamiliar technical and business domains quickly and enjoy moving between themYou care about advancing what AI systems can reliably accomplishYou use rigorous measurement and experiment design to guide decisionsYou are comfortable operating across research and production engineeringYou communicate clearly and collaborate well with people from different technical backgroundsYou are curious about the capabilities, limitations, and risks of increasingly autonomous systemsQualificationsBachelor's degree in Computer Science, Engineering, or a related field, or equivalent practical experience requiredStrong Python proficiency requiredExcellent software design, debugging, and problem-solving skills requiredExperience building and operating substantial software systems requiredDemonstrated engagement with modern AI systems, tools, or research requiredMachine learning research or engineering, including post-training, fine-tuning, reinforcement learning, or alignmentAI-agent architecture, evaluation, or tool-use environmentsDistributed systems, model serving, orchestration, or high-throughput research infrastructureSecurity sandboxing, policy enforcement, adversarial testing, or governance for AI systemsForward-deployed engineering: working closely with users to discover, build, and operationalize new capabilitiesLinux, systems performance, networking, C++, or TypeScriptThe estimated base salary range for this position is 200,000 to 300,000 USD per year (or local equivalent). This role will also be eligible for discretionary performance-based bonuses and a competitive benefits package. CultureHudson River Trading (HRT) brings a scientific approach to trading financial products. At HRT we welcome a variety of expertise: mathematics and computer science, physics and engineering, media and tech. We're a community of self-starters who are motivated by the excitement of being at the cutting edge of automation in every part of our organization—from trading, to business operations, to recruiting and beyond. At HRT we're friends and colleagues – whether we are sharing a meal, playing the latest board game, or writing elegant code. We embrace a culture of togetherness that extends far beyond the walls of our office. Use of AI tools by an applicant during interviews or assessments is strictly prohibited, unless otherwise instructed or agreed upon. If we determine that AI assistance was used by an applicant during an interview or an assessment, we reserve the right to immediately end the interview or assessment, disqualify the applicant's candidacy and/or rescind any job offers extended.