Algorithm Engineer

Harrington Starr; Greater London; On-site; GBP 80,000 - 120,000; Full time

Job summary

Harrington Starr is seeking a Senior FIX Connectivity & Algorithmic Trading Consultant to work fully remotely, preferably in South Africa. This critical role involves advising on trading architecture and execution performance, with direct influence over electronic trading systems.

The ideal candidate has deep sell-side experience, strong FIX connectivity expertise, and a proven track record in designing market-making algorithms. The position offers high trust and access to senior trading leadership.

Qualifications

• Deep sell-side experience in electronic trading infrastructure.
• Strong hands-on background with FIX connectivity (ULLink, Onix FIX or equivalent).
• Proven experience designing market-making and hedging algorithms.
• Low-latency systems expertise (Java, GC tuning, memory management, threading).
• Ability to operate autonomously in senior advisory environments.

Responsibilities

• Own the end-to-end FIX adapter migration strategy from legacy ULLink into Onix FIX.
• Define architecture and execution logic for market-making, hedging, and risk algorithms.
• Act as the authority on FIX connectivity and latency optimisation.
• Influence structure, benchmarking, and deployment of trading engines.
• Set standards for algorithm design, testing, and performance validation.

Skills

Electronic trading infrastructure

FIX connectivity

Market-making algorithms

Low-latency systems expertise

Autonomous operation in advisory environments

Technical presentation skills

South African capital markets exposure

Tools

Java

Job description

Senior FIX Connectivity & Algorithmic Trading Consultant – Capital Markets (Fintech)

• Location: Fully remote – EUR time zones (strong preference for South Africa)

This engagement sits at the sharp end of institutional trading technology. The client is a well-established capital markets participant undergoing a critical modernisation of its electronic trading stack, with a specific focus on FIX connectivity, low-latency execution and market-making infrastructure.

They are mid-way through a multi-phase transformation programme, replacing legacy FIX adapters and execution logic with a modern, high-performance Onix FIX-based architecture. This role exists because the work is business-critical — and they need senior, sellside experience to get it right.

The Role

This is a high-impact senior advisory engagement, working directly with trading, quant and technology leadership.

Responsibilities

• Own the end-to-end FIX adapter migration strategy from legacy ULLink into Onix FIX
• Define architecture and execution logic for market-making, hedging and risk algorithms
• Act as the authority on FIX connectivity, latency optimisation and order routing
• Influence how trading engines are structured, benchmarked and deployed
• Set standards for algorithm design, testing and performance validation
• Work directly with front-office stakeholders to align technology with trading intent
• Provide architectural direction without needing internal sign?off or escalation

What We’re Looking For

• Deep sell-side experience in electronic trading infrastructure
• Strong hands?on background with FIX connectivity (ULLink, Onix FIX or equivalent)
• Proven experience designing market-making and hedging algorithms
• Low-latency systems expertise (Java, GC tuning, memory management, threading)
• Ability to operate autonomously in senior advisory environments
• Comfortable presenting technical decisions to trading and senior stakeholders
• South African capital markets exposure (JSE, local market structure) is a strong advantage

Why This Role

• Direct influence on live trading architecture and execution performance
• High-trust advisory role — you are brought in for judgement, not delivery volume
• Close access to senior trading and quant leadership
• Fully remote with CET / SAST overlap
• Clear scope, urgency and decision-making authority