Senior Python Developer, Investment Technology (ETF Technology)

Selby Jennings; City Of London; Hybrid; GBP 90,000 - 130,000; Full time

Job summary

Selby Jennings is recruiting a Senior Python Developer for a global asset manager in London.

You will design and ship production-grade Python services and APIs used by portfolio managers and quants, with ownership over scalable systems across Equities, Fixed Income and Alternatives.

Qualifications

• Strong, hands-on Python with production service and API design experience.
• Experience designing scalable systems with attention to concurrency and reliability.
• Ability to translate front-office requirements into robust, production-grade software.

Responsibilities

• Design and build Python services and APIs for portfolio construction, trading, analytics, and workflows across asset classes.
• Collaborate with portfolio managers and quants to turn research tools into production platforms.
• Review AI-generated code and apply rigorous quality controls in daily work.

Skills

Python

API design

System design

Front-office collaboration

Financial services experience

Tools

AWS

PostgreSQL

SQL Server

Snowflake

Kafka

Docker

FastAPI

Job description

Senior Python Developer, Investment Technology
London Wall, hybrid (4 days on site) | Permanent

A well-established global asset manager is hiring a senior engineer to join their Investment Technology team, working directly with Portfolio Managers and Quantitative Researchers to turn internally built tools into production-grade platforms. This is a hands-on individual contributor role with real ownership over the systems you design and ship, not a data engineering seat buried in a wider platform team.

What you'll be doing

You’ll design and build Python services and APIs that support portfolio construction, trading, analytics, and operational workflows across Equities, Fixed Income, and Alternatives. You’ll partner directly with the investment side of the business, taking research tools and business-critical workflows and turning them into resilient, well-architected software. Expect real system design work: service boundaries, API contracts, concurrency, scalability, not just pipeline maintenance.

You’ll also be expected to use AI tools daily as part of how you work, Copilot, Claude, ChatGPT, or similar, and to know how to review and correct AI-generated code with the same rigour you’d apply to your own.

What we’re looking for

• Strong, hands‑on Python as your primary language, ideally 5+ years, with genuine production service and API design experience
• AWS experience across Lambda, S3, ECS/EKS, Step Functions, or Aurora
• One of PostgreSQL, SQL Server, or Snowflake used in a real production environment
• Kafka or equivalent event-driven/streaming architecture experience
• Comfort working directly with front-office stakeholders, translating business and research requirements into scalable systems
• Experience in financial services, asset management, or a similarly regulated environment is a strong plus

Nice to have: exposure to ETF mechanics (creation and redemption, basket construction, NAV/iNAV), FastAPI, dbt, or Snowpark.

The details

London Wall, four days a week on site. Permanent role, competitive base plus bonus, with genuine flexibility for exceptional candidates. No visa sponsorship or relocation support is available for this role, so applicants must already hold the right to work in the UK.

If you want a role where you’re genuinely close to the investment decisions your code supports, not several layers removed from it, this is worth a conversation.

Desired Skills and Experience

Python, AWS, Kafka, PostgreSQL, SQL Server, Snowflake, API design, microservices, system design, FastAPI, distributed systems, event-driven architecture, CI/CD, Docker, financial services, asset management, investment technology, portfolio management, quantitative research, fintech.