Beyond software functionality: Why prioritising performance testing is a must

High-profile system failures due to inadequate performance testing are never far from the headlines. Yet, many development teams still push performance testing to the back burner, heightening the risk of costly disruptions.

In this article, we explore insights from our recent webinar featuring QA experts Chris Pollard, Alan Raftery, and Nishad Bhatt and discuss why prioritising performance testing is essential for success.

What is Performance Testing?

Performance testing is a non-functional testing method that evaluates how well software performs under various conditions. It measures:

• Speed: Response times and latency.
• Stability: Reliability under sustained use.
• Scalability: Ability to handle increased traffic.

By simulating real-world scenarios, it identifies inefficiencies before they impact users or business operations, ensuring systems remain stable – even during peak demand.

Why performance testing matters

Skipping performance testing puts critical systems at risk, potentially leading to system failures, frustrated users, and financial and reputational losses. As Raftery remarked, no company wants to make headlines for a system outage.

A structured performance testing strategy helps businesses:

• Identify bottlenecks: Detect slow response times and resource constraints.
• Ensure stability: Verify system operation under expected and peak loads.
• Validate scalability: Confirm the system handles increasing traffic.
• Optimise resources: Assess CPU, memory, disk, and network usage.
• Prevent failures: Mitigate risks of crashes and downtime.
• Ensure compliance: Meet industry performance and regulatory standards.

Bhatt shared an example where Assurity tested a government login service and discovered inefficient request routing, causing delays as data looped through multiple countries. Fixing this issue improved speed, reduced costs, and enhanced user experience.

Proactive performance testing ensures systems meet real-world demand, improving reliability and preventing costly disruptions.

When is performance testing needed?

Performance testing is essential for systems that must operate reliably under load. When applications slow down or fail, the impact can be severe. Raftery highlighted the need to ask, “Are we making business decisions that will affect the IT side of our business?” If the answer is yes, then performance testing should be a priority.

Below are key scenarios where performance testing is critical:

• Mission-critical systems: Platforms that must remain operational (healthcare, trading, airline booking).
• High-traffic websites & applications: Services handling peak loads (e-commerce, banking, streaming, government portals).
• Major upgrades: Infrastructure undergoing significant modifications that affect performance (cloud migrations, database changes, IT consolidations).
• Scaling & workload changes: Systems scaling to support increased traffic or fluctuating workloads (auto-scaling, load balancing, capacity planning).
• Compliance & SLA requirements: Industries with strict performance and security requirements (healthcare, finance, government).
• API & data-intensive workloads: SaaS, backend integrations, high-concurrency transactions, big data analytics, and AI-driven applications.
• Traffic spikes: Services that must scale dynamically to maintain performance under peak loads (gaming, streaming, seasonal sales, marketing campaigns).
• Disaster recovery & failover preparedness: Ensuring uptime for applications requiring redundancy and failover validation (enterprise platforms, cloud-hosted services, consumer-facing applications) while stress-testing infrastructure resilience in failure scenarios (geo-redundant data centres, hybrid cloud environments).
• Critical business operations: Enterprise software (ERP, CRM, SCM) and internal systems that must remain responsive under heavy use (HR, payroll, inventory, manufacturing, logistics)

Applying performance testing in these situations reduces risk, ensures stability, and helps meet industry standards. Reliable systems protect reputation, customer trust, and business continuity.

Signals that say, “It’s time to test.”

Even with performance testing, real-world traffic introduces unpredictable issues. Continuous monitoring is essential to catch slowdowns, crashes, and inefficiencies before they escalate.

Key performance signals to watch for:

• Slow response times & degradation: Lagging page loads, delayed API responses, and declining performance often point to inefficiencies in code, memory management, or background processes.
• System errors & failures: Frequent timeouts, HTTP errors (500, 503), and crashes under load indicate weak system stability.
• High resource utilisation: Persistent CPU/memory spikes, excessive disk I/O, and inefficient caching suggest workload mismanagement.
• Database performance issues: Slow queries, frequent deadlocks, or high latency signal inefficiencies affecting system performance.
• Scalability challenges: Poor load balancing, increasing user traffic, and low throughput signal the need for better capacity planning.
• User complaints & SLA violations: Increased customer complaints, missed SLAs, and inconsistent system behaviour highlight performance instability.
• API & third-party dependencies: Slow API responses or inefficient third-party integrations introduce performance risks.
• Batch processing delays: Long-running scheduled tasks, batch job failures, and concurrency issues indicate inefficiencies in background processing.

As Raftery pointed out, customer feedback is often the first sign of performance issues. Identifying these signals helps QA teams address problems before they escalate into costly failures.

Infrastructure optimisation

Performance testing is more than preventing failures – it helps businesses allocate resources efficiently. A common misconception is that auto-scaling always works seamlessly. However, as Raftery noted, vendor-recommended architectures often introduce inefficiencies.

By identifying inefficiencies early, businesses can fine-tune scaling, optimise workload distribution, and reduce infrastructure costs while maintaining reliability.

Conclusion

As technology stacks evolve and business needs grow, embedding performance testing into the IT strategy is imperative. Pollard emphasised that organisations often wait too long to test, leading to late-stage discoveries of performance bottlenecks. Raftery stressed assessing performance from the architectural stage rather than as an afterthought.

Prioritising performance testing ensures smooth customer experiences, maintains compliance, and optimises cloud costs. IT leaders who embed performance testing into their strategy gain a competitive advantage, delivering reliable, high-performing applications that meet real-world demand.

Are you looking for a flexible, cost-effective way to test performance?

Assurity’s PerformanceFlex is a fast, efficient, and scalable solution that sidesteps the need for in-house infrastructure and expertise. PerformanceFlex offers:

• Seamless testing in a cloud-based environment
• Cost reductions of up to 80% compared to in-house testing
• Instant scalability to meet fluctuating demands
• Comprehensive testing to ensure system reliability
• Expert support when you need it

Learn more about PerformanceFlex

Want more performance testing insights?

Watch the webinar ‘Performance Testing: Ensuring software runs beautifully’ with QA experts Chris Pollard, Alan Raftery, and Nishad Bhatt as they explore key topics, including:

• Business and technical signals that call for testing
• Cost optimisation and resource planning
• Testing techniques and collaboration
• Why shift-left works in performance testing
• Build or outsource? Choosing the right approach
• Real-world performance testing examples

Watch the webinar video now

Download the webinar transcript