Software Developer

Affinity Labs

Affinity Labs

Software Engineering
London, UK
Posted on Nov 14, 2025
At Mustard, we value quick delivery and real-world impact over perfect code. If you're an engineer who thrives on solving problems quickly and enjoys a flexible, outcome-focused culture, you'll fit right in.

What You'll Work On:

  • Expand our access to new liquidity providers, through advanced web scraping and reverse engineering techniques
  • Develop and maintain low-latency real-time data feeds, based on the data extracted, to support trading strategies
  • Enhance system visibility for our teams to provide insight into integration issues and improvements

We work with an agile approach, following a flexible plan that adapts to new information and opportunities as they arise. Developers are a core part of this process, taking full ownership of their software throughout its lifecycle—from design and development to testing, review, and production support.

Key Responsibilities

  • Design and Build Impactful Features: Develop new features that align with and drive our business goals, delivering high-quality code that brings measurable value
  • Collaborate on Code Quality: Review and test code from teammates to ensure functionality, maintainability, performance, and quality standards
  • Support in Production: Take ownership of your team's software in production, ensuring stability and quickly addressing any issues that arise
  • Cross-Team Collaboration: Work closely with other development teams on cross-functional projects, and partner with traders and quants to design and implement the best solutions to real business problems
  • Participate in Out of Hours Support for our Software Systems


Core Tech Stack:

  • Languages: Python (Python 3.10+), JavaScript/TypeScript for frontend work, and Go for select infrastructure
  • Tools: RabbitMQ and Kafka for messaging, PostgreSQL and Redis for data storage
  • Environment: Linux servers
  • Observability: OpenTelemetry, Prometheus, Grafana and Zabbix


Requirements


Must-Haves:

  • Strong background in software development, with strong experience with Python
  • A degree in Computer Science or a numerical subject from a top university
  • Exceptional communication skills, enabling you to convey complex technical ideas clearly to both technical and non-technical audiences
  • Strong decision-making abilities, with a knack for making thoughtful trade-offs in both implementation and architectural choices, balancing innovation and practicality
  • Experience with web scraping and reverse engineering techniques, including working against bot protection tooling


Nice-to-Haves:

  • Familiarity with building event-driven systems
  • Comfort with Linux/Unix environments
  • Track record of driving successful cloud migrations, ideally to AWS, including setting up secure, scalable account and access structures


Benefits


Why join Mustard Systems?

  • Work on cutting-edge systems in a competitive and innovative field
  • Collaborate with a smart, driven team, where your contributions directly impact business performance
  • Opportunity to drive the company's technical direction and double its revenue in the next three years


Comprehensive benefits, including:

  • Competitive salary and significant bonus potential
  • Enhanced pension match with salary sacrifice option
  • Health insurance and life assurance
  • Sabbatical leave after five years
  • 33 days of annual leave (including bank holidays)
  • Seniority level

    Mid-Senior level
  • Employment type

    Full-time
  • Job function

    Engineering and Information Technology
  • Industries

    IT Services and IT Consulting