Senior Kotlin Backend Engineer

Senior Kotlin Engineer

Location: London, Sheffield or Leeds - Will require ad-hoc travel to all locations

Duration: Initial 3-month contract

Start Date: ASAP

Clearance: Live and Active SC Clearance

IR35 Status: Inside IR35

The Opportunity

We are seeking an experienced Senior Backend Engineer to join a high-performing engineering team delivering critical digital services for a major UK Government client.

This is an excellent opportunity for a highly skilled backend specialist with strong Kotlin expertise to work on large-scale, user-focused platforms. You will play a key role in designing, building and enhancing modern cloud-based services while collaborating closely with engineers, architects, product teams and stakeholders.

The successful candidate will be a hands-on engineer who is passionate about software craftsmanship, advocates engineering best practices, and enjoys working within collaborative Agile environments.

Key Responsibilities

• Design, develop and maintain scalable backend services using Kotlin and Java.
• Build and enhance microservices-based applications using Spring Boot.
• Champion Test-Driven Development (TDD) and engineering best practices.
• Participate in pair programming sessions, code reviews and technical discussions.
• Collaborate with multidisciplinary teams to deliver high-quality digital solutions.
• Contribute to technical direction, continuous improvement initiatives and knowledge sharing across the team.
• Ensure solutions are secure, maintainable and aligned with modern software engineering standards.

Essential Skills & Experience

• Strong commercial experience as a Senior Backend Engineer, Lead Engineer, or similar role.
• Expert-level Kotlin development experience.
• Strong Java and Spring Boot expertise.
• Proven experience building and supporting backend APIs and microservices.
• Demonstrable Test-Driven Development (TDD) experience.
• Strong understanding of software design principles and engineering best practices.
• Experience working within Agile delivery environments.
• Excellent communication and collaboration skills.

Desirable Experience

• Experience delivering projects within UK Government or public sector environments.
• Cloud platform experience (AWS, Azure or GCP).
• CI/CD pipeline experience.
• Experience working on large-scale digital transformation programmes.
• Familiarity with DevOps and modern engineering practices.