Senior+ Python Developer

Overview

Senior Software Engineer – Python | Microservices | AWS

📍 Hybrid (Central London - 2–3 days a week)

📈 Profitable, Series A Gov/Sec Tech Scale up

High-trust work with real-world impact across public safety and financial systems

We’re partnered with a well-funded, Series A stage Gov/Sec Tech startup operating in the blockchain analytics space.

You d build software to support use cases such as financial crime prevention, terrorism risk analysis and crypto market safety. Much of their work sits under NDA, but the impact is tangible and meaningful.

They’re around 25–30 people today and growing quickly.

We re hiring a Senior/Senior+ Software Engineer to work closely with the Head of Engineering in an autonomous, hands-on role. This is an elevated senior position for someone who enjoys being close to the code, taking ownership of complex, high scale, backend systems, and solving ambiguous technical problems.

You’ll be designing and building core backend software and infrastructure in a microservices environment, with real influence over architecture, standards and how the platform evolves as the team scales.

The tech stack today includes Python (FastAPI), Temporal for workflow orchestration, Kubernetes and Docker on AWS, with SQL-based databases and system-to-system integrations across services.

This is a high-impact senior role in a business that already has real customers, real revenue and real-world consequences to its work. You’ll be trusted with autonomy, given big technical responsibility, and have the opportunity to shape both the platform and the engineering culture as the team grows.

• Design and build core backend software and infrastructure in a microservices environment.
• Work closely with the Head of Engineering in an autonomous, hands-on role.
• Take ownership of complex, high-scale backend systems and solve ambiguous technical problems.
• Influence architecture, standards and how the platform evolves as the team grows.
• Contribute to shaping engineering culture and practices as the team expands.

• 5+ years commercial backend engineering experience
• Strong Python background (other languages such as GO are fine if you re happy to move into Python)
• Experience building and running systems at scale (100k+ users or equivalent data volumes)
• Exposure to cloud-hosted microservices architectures
• Experience contributing to architectural decisions in previous roles

• Docker and Kubernetes experience in production environments
• Terraform or infrastructure-as-code exposure
• Big Query / Big Table or large-scale data systems
• Blockchain domain experience or interest (not required)