Software Development Engineer in Test (SDET)

Software Development Engineer in Test (SDET)

Location: Hybrid – 4 days in the Leatherhead office, 1 day from home

Job Type: Full-time

The Role

We’re hiring a Software Development Engineer in Test (SDET) to design, build and maintain automation frameworks that ensure the performance, reliability, and stability of our applications. You’ll combine strong software engineering skills with a quality-led mindset to advance our automation strategy and influence how the engineering team delivers high-quality software.

Key Responsibilities

Test Automation & Framework Development

  • Develop and maintain robust automation frameworks for UI, API, and backend testing.
  • Build automated test suites integrated with CI/CD pipelines.
  • Enhance tools, libraries and utilities that support reliable and scalable automation.

Quality Engineering

  • Apply structured test design, coverage analysis, and preventative quality techniques.
  • Work closely with developers to embed testability into code and architecture.
  • Drive improvements through root-cause analysis and continuous refinement of processes.

Testing & Validation

  • Write and execute automated and occasional manual test cases.
  • Validate functional and non-functional behaviour, including performance and regression areas.
  • Participate in code reviews with a focus on quality, performance and maintainability.

Collaboration & Continuous Improvement

  • Partner with engineering and product teams to define requirements and acceptance criteria.
  • Champion best practices in automation and contribute toward a shift-left testing approach.
  • Mentor colleagues on tools, frameworks and automation methods.

Required Skills & Experience

  • Degree in Computer Science, Engineering or equivalent experience.
  • Strong programming skills in Java (preferred), Python, C#, or JavaScript.
  • Experience building automation frameworks using Selenium, Playwright, Cypress, JUnit/TestNG.
  • Solid understanding of unit, integration, system, and regression testing.
  • Hands-on experience with API testing tools (Postman, REST Assured) and performance tools (JMeter, Gatling).
  • Familiarity with CI/CD systems (Bitbucket, Jenkins, TeamCity) and containerisation (Docker, Kubernetes).
  • Proficiency with Git and modern version-control practices.

Desirable Skills

  • Experience with cloud platforms (AWS preferred).
  • Understanding of microservices, distributed systems, and event-driven architecture.
  • Experience with contract testing frameworks such as Pact.
  • Familiarity with observability tools (Prometheus, Grafana, Datadog).
  • Background in performance optimisation and scalability testing.
  • Exposure to security testing or DevSecOps practices.

Soft Skills

  • Strong analytical and problem-solving capabilities.
  • Excellent communication and team collaboration skills.
  • Comfortable working both independently and within an agile environment.
  • Motivated by continual learning and driving improvements in product quality.

Job Details

Company
4Square Recruitment Ltd
Location
Leatherhead, Surrey, England, United Kingdom
Hybrid / Remote Options
Employment Type
Full-Time
Salary
£50,000 - £60,000 per annum
Posted