Software Developer
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:
Key Responsibilities
Must-Haves:
Why join Mustard Systems?
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
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
- 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
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
- 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
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
- 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)
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Seniority level
Mid-Senior level -
Employment type
Full-time -
Job function
Engineering and Information Technology -
Industries
IT Services and IT Consulting