Senior Non-Functional Test Engineer - Active SC Clearance - Inside IR35

Job Description

We are seeking an experienced, highly skilled and 100% hands-on Senior Test Engineer to design, develop and implement advanced automated testing solutions for enterprise applications, digital services, REST APIs and complex microservices-based systems.

The successful candidate must demonstrate strong technical expertise in API automation, UI automation, performance testing and non-functional testing, supported by strong programming skills in Java and/or TypeScript.

This is a senior technical engineering role requiring the ability to independently design and develop automation frameworks, build and execute complex performance tests, analyse technical issues and contribute directly to software delivery.

The role is primarily hands-on, rather than focused on test management, governance or strategy.

Key Responsibilities

Performance & Non-Functional Testing - Critical Requirement

• Independently design, develop, configure, execute and analyse performance testing solutions using Apache JMeter, BlazeMeter, Gatling, k6 or equivalent tools.

• Build performance test scripts and test plans from scratch, including parameterisation, correlation, assertions and realistic workload modelling.

• Design and execute load, stress, spike, endurance/soak, scalability and capacity tests.

• Define realistic performance scenarios, concurrent-user models, workload profiles and performance acceptance criteria.

• Analyse response times, p95/p99 latency, throughput, concurrency, error rates and infrastructure resource utilisation.

• Investigate performance bottlenecks across APIs, microservices, databases and application infrastructure.

• Collaborate with development and DevOps teams to identify root causes and recommend technical improvements.

• Perform other relevant NFT activities, including reliability, resilience, stability, accessibility and security-related testing.

• Produce detailed technical performance reports, findings, risks and recommendations.

API Test Automation

• Independently design, develop and maintain scalable REST API automation frameworks using Java with REST Assured and/or TypeScript-based frameworks.

• Develop reusable, maintainable automated API tests covering functional, integration, regression, contract and negative scenarios.

• Implement complex API validations, authentication testing, data-driven testing and reusable test utilities.

• Design automation solutions for REST APIs and large microservices architectures.

• Troubleshoot complex API failures and collaborate with developers to resolve integration defects.

UI Test Automation

• Design, develop and maintain robust UI automation frameworks using Playwright with TypeScript and/or Selenium WebDriver with Java.

• Build scalable automated functional, regression, smoke and end-to-end UI test suites.

• Implement Page Object Model, reusable components, fixtures, assertions and test data management.

• Improve automation stability, parallel execution, cross-browser coverage and maintainability.

• Investigate complex automation failures and eliminate flaky tests.

Test Framework Engineering, CI/CD & Agile Delivery

• Design, develop, maintain and troubleshoot reusable API, UI and performance automation frameworks.

• Apply clean code principles, appropriate design patterns and automation engineering best practices.

• Integrate automated API, UI and performance tests into CI/CD pipelines using Jenkins, Azure DevOps, GitHub Actions or equivalent tools.

• Implement continuous testing and appropriate quality gates within software delivery pipelines.

• Work closely with developers, DevOps engineers, architects and testers in multidisciplinary Agile teams.

• Participate in technical design discussions, code reviews, defect investigations and continuous improvement.

• Provide hands-on technical guidance, mentoring and knowledge sharing while remaining directly involved in automation development.

Mandatory Skills and Experience

• Hands-on Performance Testing: Extensive practical experience personally developing, executing, troubleshooting and analysing performance tests.

• Performance Test Engineering: Proven ability to independently build performance scripts and test plans from scratch, including parameterisation, correlation, workload modelling and test data management.

• Performance Tools: Strong hands-on experience with Apache JMeter or equivalent performance testing tools.

• Performance Analysis: Experience analysing latency, throughput, concurrency, error rates, resource utilisation and identifying performance bottlenecks.

• Non-Functional Testing: Proven experience conducting load, stress, endurance and other relevant NFT types.

• API Automation: Strong hands-on experience designing and developing automated REST API tests using Java/REST Assured and/or TypeScript-based frameworks.

• UI Automation: Strong experience designing and developing automated UI tests using Playwright/TypeScript and/or Selenium/Java.

• Programming: Strong practical Java and/or TypeScript programming skills, with the ability to develop reusable, maintainable automation code.

• Automation Framework Engineering: Experience independently designing, building, maintaining and troubleshooting automation frameworks.

• Microservices: Experience testing complex REST APIs, enterprise applications and microservices-based architectures.

• CI/CD: Strong experience integrating automated API, UI and performance testing into delivery pipelines.

• Agile Delivery: Extensive experience working within multidisciplinary Agile development teams.

Desirable Skills and Experience

• Advanced experience with BlazeMeter, Gatling, k6 and Azure Load Testing.

• Experience with performance monitoring and observability tools, including Grafana, Prometheus, Dynatrace and Application Insights.

• BDD frameworks such as Cucumber and Serenity BDD.

• API contract testing and service virtualisation.

• Accessibility testing against WCAG standards and security testing against OWASP principles.

• Docker, Kubernetes, AWS and Microsoft Azure.

• Experience with high-volume enterprise applications, large distributed systems and cloud-native architectures.

• Experience working on UK public sector projects.

• Active SC clearance and immediate availability, subject to client confirmation.

Mandatory Candidate CV Requirements

Candidates must provide clear evidence of:

1. API Automation Development: REST API automation frameworks and test scripts personally designed and developed using Java or TypeScript.

2. UI Automation Development: UI automation frameworks and regression suites personally developed using Playwright or Selenium.

3. Performance Test Development: JMeter or equivalent performance test scripts personally built from scratch, including workload modelling, correlation and parameterisation.

4. Performance Test Execution: Load, stress, endurance or scalability tests personally executed.

5. Performance Analysis: Technical analysis of response times, throughput, error rates and performance bottlenecks, including examples of improvements or recommendations.

6. Framework Engineering: Reusable automation frameworks personally designed, maintained and troubleshot.

7. CI/CD Integration: API, UI and performance tests integrated into automated delivery pipelines.

8. Hands-on Technical Ownership: Specific examples of complex testing problems solved through direct coding, Scripting and technical investigation.

Important: Candidates whose experience is primarily focused on test leadership, strategy, governance, management or executing pre-existing performance scripts without hands-on test development experience will not meet the essential requirements.