Senior Backend Engineer (up to £175k)

Dex; Greater London; On-site; GBP 120,000 - 160,000; Full time

Job summary

Dex, a partner company of a leading AI-for-finance platform in London, seeks a senior backend engineer to own core services end-to-end and architect data pipelines for sensitive financial data. You will influence design reviews and mentor engineers as the platform scales in a regulated environment.

You will work with Python, FastAPI, PostgreSQL, Docker/Kubernetes, and cloud platforms to deliver high-throughput, secure backends and collaborate with ML engineers to productionise models.

Qualifications

• 7+ years of backend engineering experience with production systems.
• Expert-level Python, FastAPI, and PostgreSQL query optimisation.
• Experience with Docker/Kubernetes and cloud platforms.

Responsibilities

• Architect and build scalable backend services and APIs for an AI workspace handling sensitive financial data.
• Design and implement high-performance data pipelines for large-scale financial datasets with strict accuracy and latency requirements.
• Optimise database schemas, queries, and indexing strategies for PostgreSQL in a high-throughput, distributed environment.
• Partner with ML engineers to productionise models, integrating them into robust backend systems.
• Lead technical design reviews, mentor engineers, and contribute to shaping the engineering culture as the platform scales.

Skills

Backend engineering

Python

FastAPI

PostgreSQL tuning

Distributed systems

Docker/Kubernetes

Cloud platforms

Security & compliance

Event-driven

Tools

Kafka

Celery

Job description

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process.

The role

This company builds an AI workspace for sensitive financial data, serving some of the world's largest regulated institutions. Think workloads where SOC 2, GDPR, and FCA compliance aren't just buzzwords, but fundamental to the product. They've secured significant Series A funding from leading investors and are scaling fast.

You'll join a lean, senior backend team, reporting directly to the founders, at the intersection of AI and finance. This is a staff-track IC seat with visible influence, architecting core services and data pipelines. It's for an engineer who wants to own critical systems end-to-end, not just maintain a small component of a larger platform.

The work

• Architect and build scalable backend services and APIs for an AI workspace handling sensitive financial data.
• Design and implement high-performance data pipelines to process large-scale financial datasets with strict accuracy and latency requirements.
• Optimise database schemas, queries, and indexing strategies for PostgreSQL in a high-throughput, distributed environment.
• Partner with ML engineers to productionise models, integrating them seamlessly into robust backend systems.
• Lead technical design reviews, mentor engineers, and contribute to shaping the engineering culture as the platform scales.

What You Bring

• 7+ years of backend engineering experience, with a track record of building and scaling production systems.
• Expert-level Python, modern web frameworks (FastAPI), and deep expertise in PostgreSQL query optimisation and scaling.
• Experience with event-driven architectures, message brokers (e.g., Celery, Kafka), and designing clean REST APIs and microservices.
• Strong fundamentals in distributed systems, cloud platforms (Azure preferred), Docker/Kubernetes, and security (authn/authz, encryption).
• Experience shipping software in regulated environments (SOC 2, GDPR, FCA) is a significant advantage.