Senior Backend Developer

Senior Backend Developer - Ruby/Elixir

Location: London - Remote

Outside IR35

Immediate starter.

We're supporting a technology business undertaking a major modernization programme and are looking for a Senior Backend Developer to drive a large-scale refactoring initiative across a complex, multi-service platform.

This is a hands-on role for someone who enjoys untangling legacy code, improving architecture, and leaving systems in a measurably better state than they found them. You'll combine deep engineering capability with pragmatic technical leadership to deliver safer, faster, and more scalable services.

What you'll be doing:

• Lead end-to-end refactoring across multiple backend technology stacks

• Redesign and modernise the messaging and event architecture

• Improve database performance, reliability, and schema design

• Reduce technical debt while keeping business disruption to a minimum

• Define and embed engineering standards and maintainability practices

• Support and mentor engineers working alongside you

What you'll need to bring:

Backend engineering

• Strong commercial experience with Elixir including OTP, GenServers and Phoenix

• Expert use of Ruby

• Roughly 5+ years working across both ecosystems

Data layer

• Advanced optimisation and performance tuning in MySQL

• Strong knowledge of PostgreSQL, including complex queries and administration

• Confidence managing migrations and schema evolution

Messaging & distributed systems

• Strong experience with Google Cloud Pub/Sub or comparable technologies such as RabbitMQ, Apache Kafka, or Amazon SQS

• Practical understanding of event-driven patterns, ordering, retries, and delivery guarantees

Experience that will set you apart:

• 7+ years in backend engineering roles

• Proven ownership of significant refactoring or modernisation programmes

• Background in microservices and distributed architectures

• Track record improving scalability and performance in production systems

• Experience moving legacy estates toward modern designs

We are an equal opportunities employer and welcome applications from all suitably qualified persons regardless of their race, sex, disability, religion/belief, sexual orientation, or age.