You build backend systems that stay up when things get ugly.
You care about correctness, performance, and clarity over cleverness.
You want your code to power decisions involving real money.
If you have only worked on internal tools or low-impact services, this is not the role.
You will build the backend systems that power Reflexivity’s AI-driven investment platform.
This role exists because scale, data complexity, and latency matter deeply in finance.
You will work closely with AI and product teams to ship production-grade systems.
- Build and maintain Golang services that power core product workflows
- Design APIs and data pipelines used by AI and reasoning systems
- Improve system performance, reliability, and observability
- Review and challenge designs to keep systems simple and scalable
- Debug production issues with speed and discipline
After 3 months:
You ship production code confidently and understand system trade-offs.
After 6 months:
You own critical services and improve their performance or reliability.
After 12 months:
You influence architecture decisions and mentor other engineers.
- 5 plus years backend engineering experience
- Strong Golang experience in production systems
- Startup experience on a core product
- Experience working with data-heavy systems
- Comfortable using AI-assisted coding tools daily
- Fintech or investment domain exposure
- Experience supporting ML or LLM systems
- Distributed systems or low-latency data pipelines
- Engineers own systems end to end
- Clear accountability and direct feedback
- In-office team with high trust and high ownership
- Work on systems that directly affect investor outcomes
- Strong technical ownership
- High bar engineering culture without bureaucracy
- £80,000 to £160,000 depending on experience
- Equity included
- In-office role based in London
- No agencies
Skills Required
- 5+ years backend engineering experience
- Strong Golang experience in production systems
- Startup experience on a core product
- Experience working with data-heavy systems
- Comfortable using AI-assisted coding tools daily
- Fintech or investment domain exposure
- Experience supporting ML or LLM systems
- Distributed systems or low-latency data pipelines
- In-office role based in London
What We Do
We empower organizations and institutions with the capabilities to more effectively identify mental health challenges to ensure patients, team members, and constituents receive the care they need. Toggle offers a new form of artificial intelligence that merges advances in computational cognition with machine learning. We call it Comp Cog AI, and it predicts anxiety, depression, and suicidal planning using a single 3-minute assessment involving images. Its accuracy is cutting-edge against peer-reviewed findings for these three mental health challenges and is immune to manipulation or gaming, ensuring highly repeatable results. Fast, accurate & inexpensive, Toggle’s solution is built on the latest developments in neuroscience and supported by deep academic review and competitive government funding. Example Use Cases: - Rapid & regular screening for Military, Defence and Public Safety personnel - Screen for mental health during every visit to the Emergency Room or Medical Clinic - Triage and best route callers in crisis line and telehealth environments - Regularly assess at-risk groups remotely, triggering outreach where needed - Offer screening to students and the workforce to deliver timely intervention
