Core Developer (London)

G-20 Group; Greater London; On-site; GBP 67,000 - 98,000; Full time

Job summary

A leading financial technology firm in Greater London is seeking a highly skilled Core Python Developer to enhance its proprietary trading engine. The ideal candidate has a strong background in developing large-scale low-latency systems and will handle core components such as trading and pricing strategies. Responsibilities include optimizing performance and collaborating with trading teams. This position requires at least 5 years of software development experience, preferably in a fast-paced trading environment, and expertise in Python and related technologies. The role is full time in the London office, and applicants must have the right to work in the UK.

Qualifications

• At least 5+ years’ experience in software development, ideally in a high-paced trading environment.
• Familiarity with low latency and high throughput systems is preferred.
• Experience in the finance or cryptocurrency sectors is nice but not mandatory.

Responsibilities

• Develop and maintain trading engine components.
• Optimize trading engine performance and ensure smooth daily operations.
• Collaborate with the trading team to deliver solutions aligned with strategic goals.

Skills

Python

Async

Unix based systems

Real-time data messaging (Redis, websockets)

CI/CD tools (Jenkins, Supervisor, Docker)

Problem-solving skills

Education

Bachelor’s or Master’s degree in Computer Science or Engineering

Job description

About G20 Group

The G-20 Group is a pioneer in Quantitative Trading systems in cross-asset markets. Headquartered in Switzerland, we operate at the intersection of Quantitative Research, Software Engineering and Trading. The team combines a startup mindset with extensive experience in proprietary Trading, Technology and Quantitative Finance.

Role Overview

The G-20 London Office is seeking a highly skilled and motivated Core Python Developer to further develop and maintain the proprietary, in-house trading engine.

We are seeking a candidate with a strong background in building large-scale low-latency systems. The role involves maintaining daily trading operations as well developing scalable, high-performance code, optimizing system architecture and modularity to ensure seamless operations and functionality.

The ideal candidate will be self-driven, motivated, responsible and highly responsive, working independently to develop and improve the existing code base, while collaborating closely with diverse cross-functional teams of stakeholders and fellow developers. We are looking for someone with strong expertise in python programming, debugging, and system optimization, who is passionate about delivering practical, high-quality, PnL-focused solutions.

The primary focus for this role will be working on core engine components, including trading engines, pricing, market making strategies and underlying trading infrastructure.

Key Responsibilities

• Trading Engine Development: Develop the existing and new components within the trading engine while maintaining overall system design.
• Ownership of Engine Components: Grow into ownership of existing or newly developed trading engine components, such as pricing, market‑making, hedging, etc.
• Performance Optimization: Continuously monitor and optimize trading engine performance.
• Systems Refactorization: Work on appropriate code modularization, versioning, deployment and test processes.
• Trading Infrastructure Development: Develop, improve and maintain overall trading infrastructure, including reference and market data, trades and balance dissemination services.
• Trading Engine Operations: Ensure that day‑to‑day trading operations run smoothly.
• Collaboration with Trading: Work directly with the trading team to understand their needs and deliver appropriate solutions that support the firm’s strategic goals.

Education and Experience

• Education: Bachelor’s or Master’s degree in computer sciences, Computer Science, Engineering, or a related field.
• Experience: At least 5+ years’ experience in software development, ideally in a high‑paced trading environment.

Personal Qualities

• self-driven, motivated, responsible and highly responsive individual.
• mature enough to work collaboratively on the existing code base.
• ability to work effectively in a fast-paced trading environment.
• strong and tactful communication skills, both verbal and written

Tech Skills

• Proficiency in Python and Async. Rust and React.js are bonuses.
• Proficiency in Unix based systems.
• Experience of cloud‑based platforms (e.g. AWS).
• Experience with real-time data messaging (e.g. Redis, websockets).
• Experience with CI/CD tools, Jenkins, Supervisor and docker in particular
• Fast problem‑solving skills, combined with attention to details

Preferred / Desirable Experience

• Familiarity with low latency and high throughput systems.
• Experience in the finance or cryptocurrency sectors is nice but not mandatory.
• Experience with high‑paced production or trading environments.

Deadline for applications: January 9th, 2026

Location and Right to Work

This role will be based full time from our London office. Only candidates who possess the right to work in the UK need apply.

Join G-20 and be a part of a team that is at the forefront of financial markets, driving innovation and excellence in the sector.