Senior Python Engineer, Investment Platform

Location: London, UK We are looking for a Senior Python Engineer who writes production code every day. You will build new components and refactor business-built tools into well-engineered applications. You will work directly with portfolio managers to understand how the tools are used and what must not break. This is a 100% hands-on role, not an advisory or architectural role. This is a hybrid position requiring onsite presence at the client’s London office three days per week. Duration: 12+ months Design, develop, and maintain production-grade Python applications and APIs. Refactor and modernize Python/Excel tools built by business teams by adding tests, structure, security, and observability. Work directly with portfolio managers and front-office users to clarify requirements and validate results. Build data-intensive and analytics features using SQL and cloud data platforms. Contribute to CI/CD, automated testing, and code reviews. Apply AI-assisted development practices where they improve speed and quality. 5+ years of hands-on experience in production Python development. Python is the main language in your current role. ETF or investment front-office experience (asset management, investment banking, or capital markets). At a minimum, you have worked directly with portfolio managers or traders. Experience modernizing legacy or business-built applications. Strong SQL skills and experience with cloud platforms (AWS preferred). Experience with API design and integration, automated testing, CI/CD, and Git. Ability to gather requirements directly from business users and communicate clearly with non-technical stakeholders. Ability and willingness to work on-site at the client’s London office three days per week. Experience with fixed-income ETFs, portfolio management, or investment analytics. Experience with Aladdin, BNY, or comparable investment platforms. Experience with Snowflake, Redshift, Databricks, or BigQuery. Experience with AI-enabled development, agentic workflows, or AI-assisted SDLC.