Are you an engineer who thrives in a fast-paced, experimental environment? Do you relish the challenge of building complex data systems, testing ideas, and learning from failure as much as success? Mustard Systems is seeking a Senior Data Engineer to join our talented and high-growth Horse Racing team, where you'll collaborate with a unique blend of mathematicians, statisticians, international chess masters, and Countdown Octo-Champs to tackle some of the most complex and exciting problems in sports prediction.What You Won't Have To Do In This RoleBe bogged down by red tape or excessive bureaucracyCheck in repeatedly or wait for permission to try new ideasAim for perfect code or endless code reviewsThe Horse Racing team specialises in predicting the outcomes of Horse Racing around the world, building in-house sophisticated trading systems and predictive models.In this role, you'll work alongside some of the sharpest minds in the industry, in a culture that values creativity, experimentation, and diversity of thought. If you're ready to make an impact by innovating at the cutting edge of sports prediction, we'd love to hear from you.This isn't a role for a by-the-book engineer. Instead, it's perfect for someone who enjoys exploring uncharted territory, using their technical expertise to experiment, innovate, and deliver rapid results.What You'll DoBuild and maintain the data infrastructure that powers our trading operations. This includes:Building and maintaining data pipelines that ingest data from multiple external providers, APIs, and real-time feedsDesigning and implementing streaming data architectures to support low-latency trading requirementsOptimising our data warehouse for both cost and performance as data volumes growEnsuring data quality and reliability through testing, validation, and CI/CD best practicesImproving observability, monitoring, and alerting around data freshness, volume anomalies, and pipeline healthPartnering with quantitative analysts and traders to understand data requirements and deliver robust solutionsMentoring other team members on technical decisions and best practicesRequirementsWhat We're Looking For5+ years of experience in data engineering, with deep experience in Python, SQL, and data modellingExperience with cloud data warehouses, orchestration frameworks, and transformation toolsHands-on experience with streaming technologies (Kafka or similar)Experience integrating data from external APIs and third-party providersExperience working in environments where the speed of development is prioritised over formal processesA self-starter attitude, with the confidence to take ownership of projects and experiment with new ideasStrong decision-making abilities, with a knack for making thoughtful trade-offs balancing speed, quality, and maintainabilityExcellent communication skills - able to discuss technical concepts clearly with both technical and non-technical colleaguesA degree in Computer Science or a numerical subject from a top universityNo prior knowledge of horse racing is required.Our Tech StackYou'll have the freedom to choose the tools and technologies that fit each problem best, but here's a snapshot of what we currently use:Snowflake for data warehousingDagster for orchestrationPython 3.12+DBT for transformationsKafka for streamingClickHouse for real-time analyticsOn-Prem (Linux) + AWSYour Portfolio or Personal ProjectsWe're especially keen to see what you've built outside of your day job. Whether it's a passion project, an experimental tool, or something a little quirky, we'd love to hear about it. These projects often tell us more about your creativity and approach to problem-solving than a standard CV ever could.BenefitsWhy join Mustard Systems?Hybrid working environment. We're in the office every Monday, Tuesday and Thursday, and work from home every Wednesday and Friday Work on cutting-edge systems in a competitive and innovative fieldCollaborate with a smart, driven team, where your contributions directly impact business performanceOpportunity to drive the company's technical direction and double its revenue in the next three yearsComprehensive benefits, including:Competitive salary and significant bonus potential Enhanced pension match with salary sacrifice optionHealth insurance and life assuranceSabbatical leave after five years33 days of annual leave (including bank holidays)