Performance Test Manager

Realtime Recruitment Limited; Milton Keynes; On-site; GBP 70,000 - 110,000; Full time

Job summary

Realtime Recruitment Limited is seeking a Performance Test Manager on a day rate contract outside IR35. You will own performance testing strategy from planning through delivery, ensuring systems meet workload, response time, and scalability targets across complex tech environments.

Lead the design and execution of load, stress and capacity tests, partner with architecture and operations to enable observability, and provide evidence-based assurance for release decisions.

Qualifications

• Proven track record leading performance testing in complex environments.
• Strong skills in workload modelling, monitoring and capacity analysis.
• Hands-on with established performance testing tools and observability platforms.
• Good understanding of cloud, APIs, databases and distributed architectures.

Responsibilities

• Set and maintain the performance test strategy, scope, plan, schedule and resourcing.
• Turn non-functional requirements into clear, measurable acceptance criteria.
• Build workload models based on business volumes, users, growth and peaks.
• Coordinate environments, tooling, data, access, and dependencies for testing.
• Lead load, stress, endurance, scalability, volume and resilience tests.
• Partner with architecture, infra, suppliers and ops to enable observability.
• Manage defects, tuning, retesting, and regression; assess remaining risk.
• Report trends, constraints and capacity risks to technical and senior teams.
• Provide evidence-based assurance for entry/exit criteria and releases.

Skills

Performance testing

Workload modelling

Test scripting

Monitoring

Capacity analysis

Performance engineering

Observability

Stakeholder management

Release risk

Tools

JMeter

Gatling

New Relic

Dynatrace

Job description

Performance Test Manager - Day Rate Contract - Outside IR35

You will take ownership of performance testing across the programme, from strategy and planning through to delivery and assurance. Your job is to make sure systems, integrations, infrastructure, and business-critical services can meet agreed expectations for workload, response time, throughput, scalability, stability, and resilience.

Key responsibilities

• Set and maintain the performance test strategy, scope, plan, schedule, estimates, and resourcing approach.
• Turn non-functional requirements and service expectations into clear, measurable acceptance criteria.
• Build realistic workload models based on business volumes, concurrent users, transaction profiles, expected growth, and peak scenarios.
• Coordinate everything testing depends on, including environments, tooling, monitoring, test data, access, stubs, and dependencies.
• Lead the design and running of load, stress, endurance, scalability, volume, and targeted resilience tests.
• Partner with architecture, infrastructure, suppliers, application teams, and operations to put observability in place and trace the root cause of bottlenecks.
• Manage performance defects, tuning cycles, retesting, and regression, and assess any remaining risk.
• Report on trends, constraints, capacity risks, and recommendations in a way that works for both technical teams and senior stakeholders.
• Provide evidence-based assurance against entry and exit criteria, and support release decisions.

Experience and knowledge

• A track record of leading performance testing in complex, interconnected technology environments.
• Solid grounding in workload modelling, test scripting, monitoring, diagnostics, capacity analysis, and performance engineering.
• Hands‑on experience with established performance testing and application monitoring tools.
• Good understanding of cloud, networks, databases, APIs, batch processing, integrations, and distributed architectures.

Skills and behaviours

• Strong in technical analysis, planning, supplier management, and communicating with stakeholders.
• Able to translate business demand into well‑founded test models and make sense of complex technical evidence.
• Calm, methodical, and focused on outcomes, with the confidence to challenge assumptions that lack evidence.

What success looks like

• Critical services are tested against realistic, agreed performance and capacity expectations.
• Bottlenecks and scalability risks are found early enough to be fixed.
• Results are repeatable, evidence‑based, clearly explained, and tied to release risk.
• Any remaining performance risks have a named owner and are formally accepted before release.