Python/Polygot Engineer (Market Data) - Inside IR35 - Up to £700 per day

Senior Full Stack Engineer – Market Data Platforms (Python / gRPC / MongoDB) Hybrid working in London Inside IR35 - Up to £700 per day We are seeking a Senior Full Stack Engineer to develop and enhance market data platforms within a Global Markets environment. You'll build scalable applications across the UI, APIs and data layers, supporting market data analytics, distribution and consumption in a high-performance, business-critical setting. Key Responsibilities Design, develop and maintain full-stack applications across UI, backend services and data layers. Build and enhance market data platforms supporting analytics, distribution and data consumption. Develop high-performance APIs and services using Python, REST and gRPC. Design and manage large-scale NoSQL data stores (MongoDB, HBase or similar). Investigate production issues, perform root cause analysis (RCA) and deliver end-to-end resolutions. Translate business requirements into scalable technical solutions. Collaborate with Trading, Analytics and Data teams to deliver robust, high-quality solutions. Drive platform performance, scalability and continuous improvement. Essential Skills Strong full-stack development experience across frontend, backend APIs and databases. Excellent Python development skills (polyglot experience beneficial). Experience building REST and gRPC services. Hands-on experience with MongoDB, HBase or other NoSQL databases. Strong debugging, troubleshooting and problem-solving skills. Experience working with large datasets and data-intensive applications. Ability to take ownership of issues through to resolution. Preferred Experience Front Office trading environments (Fixed Income, FX or Derivatives). Strong understanding of market data, trade lifecycle, pricing and risk. Experience developing enterprise market data or trading platforms. Knowledge of market data modelling, instrument reference data or metadata-heavy systems (e.g. FRTB taxonomies). Experience integrating with downstream analytics platforms and distributed systems. Exposure to cloud platforms, data streaming or real-time processing technologies. Previous experience within global banking or financial services. Experience Approximately 9–15 years' experience (flexible for exceptional candidates).