Contract Software Engineer (Java & Kotlin)

Spectrum IT Recruitment; City Of London; Hybrid; GBP 82,656 - 123,984; Full time

Job summary

Spectrum IT Recruitment is seeking a Senior Java & Kotlin Backend Engineer in London for an initial two‑month contract. Hybrid work with office attendance on Wednesdays. You will contribute to greenfield backend development, building scalable microservices and REST APIs in a cloud environment.

Join a team delivering high‑quality backend solutions, collaborating with cross‑functional stakeholders to design, develop and deploy secure, reliable systems at scale. Immediate start available.

Qualifications

• Strong commercial experience with Java and Kotlin.
• Experience building microservices with Spring Boot.
• Designing REST APIs and working in distributed systems.
• Experience with Kafka, PostgreSQL and AWS cloud services.
• Hands-on Docker/containerisation and CI/CD practices.

Responsibilities

• Design, develop and maintain backend services using Java and Kotlin.
• Build and enhance RESTful APIs within a microservices architecture.
• Develop secure, scalable applications and ensure reliability.
• Collaborate with Product Managers and engineers to deliver features.
• Participate in code reviews and improve engineering practices.
• Improve system reliability, performance and scalability.
• Work with cloud-native technologies and modern deployment practices.
• Support production systems and contribute to continuous improvement.

Skills

Java

Kotlin

Spring Boot

Microservices

REST APIs

Kafka

PostgreSQL

AWS

Docker

CI/CD

Tools

Gradle

Job description

Senior Java & Kotlin Backend Engineer

Location: London (Hybrid - Wednesday office attendance required)
Contract: Initial 2 months
IR35: Outside IR35
Start Date: ASAP

The Role

We're working with a leading technology organisation seeking an experienced Senior Java & Kotlin Backend Engineer to join their engineering team on an initial two-month contract.

This role offers the opportunity to contribute to greenfield backend development, building scalable, cloud-native microservices within a modern engineering environment. You'll work alongside cross-functional teams to design, develop and deliver high-quality backend solutions that are secure, reliable and built for scale.

Key Responsibilities

• Design, develop and maintain backend services using Java and Kotlin.
• Build and enhance RESTful APIs within a microservices architecture.
• Develop secure, scalable and high-performance applications.
• Collaborate with Product Managers, Engineers and technical stakeholders to deliver new features.
• Participate in code reviews and contribute to engineering best practices.
• Improve system reliability, performance and scalability.
• Work with cloud-native technologies and modern deployment practices.
• Support production systems and contribute to continuous improvement initiatives.

Essential Skills & Experience

• Strong commercial experience with Java and Kotlin.
• Proven experience developing applications using Spring Boot.
• Strong understanding of microservices architecture.
• Experience designing and building REST APIs.
• Commercial experience with Kafka or similar messaging technologies.
• Experience with PostgreSQL.
• Experience working with AWS cloud services.
• Hands-on experience with Docker and containerised applications.
• Strong understanding of software engineering best practices, testing and CI/CD.
• Excellent communication and problem-solving skills.

Desirable

• Experience with Gradle.
• Experience working within Agile development teams.
• Knowledge of distributed systems and event-driven architectures.

Contract Details

• Initial 2-month contract.
• Outside IR35.
• Hybrid working with office attendance in London every Wednesday.
• Immediate start available.

Spectrum IT Recruitment (South) Limited is acting as an Employment Business in relation to this vacancy.