Performance Test Engineer

Kainos; Greater London; On-site; GBP 50,000 - 70,000; Full time

Job summary

A technology services company in Greater London is seeking a Senior Associate Performance Test Engineer to join their agile team. In this role, you will develop and execute non-functional tests while collaborating with talented colleagues. Candidates should possess strong proficiency with performance testing tools and Java/Scala scripting, along with a deep understanding of performance testing principles. This position values diverse and innovative thinkers who want to make a real impact.

Qualifications

• Strong proficiency with performance testing tools like JMeter or Gatling.
• Solid knowledge of Java or Scala for scripting.
• Understanding of HTTP, REST, and API testing principles.
• Experience designing and executing performance tests.

Responsibilities

• Develop and execute non-functional tests as a part of an agile team.
• Collaborate with colleagues to learn and grow.
• Communicate performance reports and KPIs to audiences.

Skills

Performance testing tools (JMeter, Gatling)

Java (or Scala)

HTTP, REST, JSON, API performance testing

Performance, load, stress testing

Performance bottlenecks analysis

CI/CD integration (Jenkins, GitLab CI)

System metrics analysis

Cloud infrastructure (AWS, Azure)

Database performance and query optimisation

3+ years in performance testing/engineering

Tools

Grafana

Prometheus

AWS CloudWatch

Job description

Overview

Join Kainos and Shape the Future. At Kainos, we’re problem solvers, innovators, and collaborators - driven by a shared mission to create real impact. Whether we’re transforming digital services for millions, delivering cutting-edge Workday solutions, or pushing the boundaries of technology, we do it together.

We believe in a people-first culture, where your ideas are valued, your growth is supported, and your contributions truly make a difference. Here, you’ll be part of a diverse, ambitious team that celebrates creativity and collaboration.

Ready to make your mark? Join us and be part of something bigger.

Responsibilities

Main purpose of the role & responsibilities in the business:

As a Performance Test Engineer (Senior Associate) in Kainos, you’ll work within a multi-skilled agile team, developing and executing Non-Functional tests. You’ll do this whilst learning about new technologies and approaches, with talented colleagues who will help you learn, develop and grow.

Qualifications

Minimum (essential) requirements:

• Strong proficiency with performance testing tools (e.g., JMeter, Gatling)
• Solid working knowledge of Java (or Scala) for scripting and custom logic
• Deep understanding of HTTP, REST, JSON, and API performance testing principles
• Experience designing and executing performance, load, and stress tests for web and API-based systems
• Proven ability to analyse performance bottlenecks across application, database, and infrastructure layers
• Experience with CI/CD integration for automated performance testing (e.g., Jenkins, GitLab CI, TeamCity)
• Competence in analysing system metrics (CPU, memory, I/O, network) from logs and monitors
• Experience with cloud infrastructure (AWS, Azure) and distributed load testing
• Understanding of database performance and query optimisation (e.g., PostgreSQL, MySQL, DynamoDB)
• 3+ years in performance testing/engineering roles
• Demonstrated ability to collaborate with development and DevOps teams to resolve performance issues
• Experience generating and communicating performance reports and KPIs to technical and non-technical audiences
• Prior involvement in capacity planning, tuning, and production performance investigations
• Familiarity with Agile delivery and testing practices

Desirable:

• Experience building scalable and reusable performance testing frameworks
• Ability to define and maintain performance benchmarks, KPIs, and baselines
• Integration of performance testing into CI/CD pipelines for automated validation
• Experience with performance monitoring dashboards (e.g., Grafana, Prometheus, AWS CloudWatch)
• Exposure to end-to-end performance validation across cloud platforms (Azure, GCP, AWS)
• Experience with trend analysis and comparative performance reporting across releases
• Mentoring junior engineers in performance testing concepts, workload modelling, and analysis techniques

Embracing our differences

At Kainos, we believe in the power of diversity, equity and inclusion. We are committed to building a team that is as diverse as the world we live in, where everyone is valued, respected, and given an equal chance to thrive. We actively seek out talented people from all backgrounds, regardless of age, race, ethnicity, gender, sexual orientation, religion, disability, or any other characteristic that makes them who they are. We also believe every candidate deserves a level playing field.

Our friendly talent acquisition team is here to support you every step of the way, so if you require any accommodations or adjustments, we encourage you to reach out.

We understand that everyone's journey is different, and by having a private conversation we can ensure that our recruitment process is tailored to your needs.