Senior Integration Developer/ Architect

Role Overview

You will design and build robust, secure, API-led integration solutions using C# / .NET and the Microsoft Azure stack, own solution architecture and technical design, from HLD/LLD through design patterns and trade-off decisions, and provide ongoing production support to ensure the stability and performance of business-critical systems in a regulated banking environment.

This is a design-led role. We are looking for a senior engineer who operates at architect level, comfortable owning end-to-end solution design, applying design patterns and articulating design decisions, while remaining fully hands-on with development and production support.

Key Responsibilities

Solution Architecture & Design

• Own and author High-Level Design (HLD) and Low-Level Design (LLD) documentation for integration solutions.
  

• Create UML diagrams (sequence, flow, component) using Draw.io or equivalent.
  

• Define integration patterns and drive overall solution architecture, making and clearly articulating design decisions and trade-offs.
  

• Apply established software and enterprise integration design patterns, and guide their consistent use across solutions.
  

• Design event-driven and messaging architectures with proven reliability patterns (retries, dead-letter queues, idempotency, circuit breakers).
  

• Design and develop integration solutions, APIs, and workflows using C# / .NET Core and API-based architecture.
  

• Implement event-driven, asynchronous, and messaging-based integration patterns.
  

• Apply API design best practice (contract-first design, versioning, security) and manage APIs through Azure API Management.
  

• Design and optimise serverless workloads (Azure Functions), including scaling, performance, and cost considerations.
  

• Optimise databases for performance, including indexing strategies, execution plans, and query tuning (Azure SQL / Entity Framework).
  

• Enhance and maintain existing systems and interfaces.
  

• Ensure adherence to coding standards and secure development practices.
  

• Build and maintain CI/CD pipelines using Azure DevOps.
  

• Manage source code using Git-based workflows.
  

• Support automated deployment across environments.
  

• Participate fully in Programme Increment (PI) Planning, sprint planning, backlog refinement, daily stand-ups, and retrospectives.
  

• Contribute to estimation, capacity planning, and delivery commitments.
  

• Ensure all work is accurately tracked and kept up to date in Jira.
  

• Provide L3 escalation support and support L1/L2 engineers in resolving incidents.
  

• Perform root cause analysis (RCA) and resolve incidents in line with agreed SLAs.
  

• Monitor, optimise, and continuously improve system stability and performance.
  

• Produce runbooks, operational guides, and release notes, and complete knowledge transfer to support teams.
  

Essential Skills

• 8+ years' experience in software development, with strong hands-on expertise in integration and API development and proven solution-design ownership.
  

• C# / .NET Core.
  

• HLD/LLD authoring and UML-based design (Draw.io or equivalent).
  

• Software and integration design patterns, with the ability to explain design decisions and trade-offs confidently.
  

• Event-driven architecture and messaging, including reliability patterns (retries, dead-letter queues, idempotency).
  

• Azure Integration Services: Function Apps, Logic Apps, Service Bus, and API Management.
  

• Database and performance optimisation: indexing, execution plans, and query tuning.
  

• Azure DevOps and Git.
  

• CI/CD practices and automated deployment.
  

• Agile / Scrum delivery.