Senior Backend Developer

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.

Location: London - Remote

Outside IR35

Immediate starter.

• 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

Backend engineering

• Strong commercial experience with Elixir including OTP, Gen Servers 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

• 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.