Senior Developer

ML; Greater London; On-site; GBP 90,000 - 150,000; Full time

Job summary

ML in London seeks a Senior Back-End Developer to anchor a fast-moving payments platform built on .NET microservices with PostgreSQL and Redis. You will own the codebase, drive design, enforce quality, and mentor peers in a regulated payments environment.

You will design robust APIs (REST), optimise data access, and contribute to CI/CD pipelines on GKE, with security and auditability at the forefront as the team scales.

Qualifications

• Extensive production backend experience in C# / .NET, including microservices.
• REST API design experience with inter-service communication patterns.
• Strong knowledge of PostgreSQL and Redis.
• Experience with cloud deployments on Google Cloud Platform (GKE).
• Leadership or mentoring experience in an engineering team.

Responsibilities

• Lead design, development, and maintenance of .NET microservices from API design to data modelling.
• Drive code quality, architectural coherence, and technical debt reduction.
• Design robust services for payments, FX, and treasury workflows with auditability.
• Contribute to and improve GitLab CI/CD pipelines and automated testing.
• Mentor and review work of other developers; set engineering standards.

Skills

C# / .NET

REST API design

PostgreSQL

Redis

Kubernetes / GKE

CI/CD / GitLab

Cloud platform (GCP)

Mentoring

Education

Bachelor's degree in Computer Science or related

Tools

GitLab

Kubernetes

GKE

Job description

Senior Backend Developer .NET - Payments - URGENT!

My client, a leading provider of payments, fx and financial services is looking to hire a Senior backend Developer in their London based team.

Role Summary

We are looking for a Senior Back-End Developer to become the technical anchor of our newly forming in-house engineering team.

Our platform is built on a suite of .NET microservices, backed by PostgreSQL and Redis, running on Google Cloud Platform (GKE) and delivered through GitLab CI/CD. You will take deep ownership of this codebase: leading its ongoing development, raising engineering standards, and guiding the work of other developers as the in-house team grows.

This is a senior, high-influence role in a regulated payments business. The services you build and harden move real money; correctness, resilience, and security are not nice-to-haves here, they are the job.

Key Responsibilities

• Lead the design, development, and maintenance of our .NET microservices, from API design through to data modelling and integration
• Take ownership of the codebase: drive code quality, architectural coherence, and technical debt reduction across services
• Design robust, well-tested services for payments, FX, and treasury workflows, with strong attention to correctness, idempotency, and auditability
• Work with PostgreSQL and Redis for transactional data and caching, with an eye on performance and integrity
• Contribute to and improve GitLab CI/CD pipelines, including automated testing, quality gates, and safe release practices
• Mentor and review the work of other developers, in-house and external, setting the bar for engineering standards
• Collaborate with our DevOps function on observability, reliability, and secure deployment onto GKE
• Build with security and regulatory expectations in mind, and support audit and banking partner requests with technical input where needed
• Extensive commercial experience building production back-end systems in C# / .NET, including microservice architectures
• Strong API design skills (REST) and experience with inter-service communication patterns, messaging, and resilience techniques
• Deep working knowledge of PostgreSQL (schema design, query performance, transactions) and practical experience with Redis
• Experience running containerised services in Kubernetes; GKE experience is a plus
• Solid grounding in automated testing and CI/CD; GitLab experience is advantageous
• A track record of leading by example: raising standards through code review, mentoring, and pragmatic technical leadership
• Experience in payments, fintech, or another regulated environment is strongly advantageous
• Clear communication skills and the judgement to make sound technical decisions in a small, fast-moving team