Website and web application performance plays a major role in user experience, conversions, reliability, and revenue. A fast, stable website or application can help users complete tasks smoothly, while a slow or unreliable system can lead to abandoned sessions, failed transactions, and lost trust.
Companies use performance testing and performance engineering to make sure websites, web applications, and web services such as APIs are optimized for reliability, speed, stability, and scalability. Performance testing and performance engineering sound similar, but they are not the same thing. This article explains both concepts and how they work together to improve website and application performance.
What Is Performance Testing?
Performance testing evaluates how websites, applications, and APIs perform under different levels of user activity. It measures speed, stability, scalability, accessibility, responsiveness, throughput, and error behavior under load.
The goal of performance testing is to detect bottlenecks and performance issues before they affect users. By testing before launch, before a major release, or before a known traffic spike, teams can reduce downtime risk and confirm that the application can support expected demand.
The following are common types of performance testing.
Load Testing
Load testing measures website or application performance under normal and higher-than-normal traffic conditions. The goal of load testing is to understand where performance bottlenecks occur so teams can improve application stability and functionality before production users are affected.
Stress Testing
Stress testing is similar to load testing, but it pushes the application beyond expected traffic levels. The goal of stress testing is to find the breaking point and understand how the system responds, fails, and recovers.
Scalability Testing
Scalability testing shows how an application performs as user load increases or decreases. Once teams understand the maximum sustainable level, they can decide whether to improve capacity, adjust infrastructure, tune the application, or accept slower response times at certain traffic levels.
Spike Testing
Spike testing evaluates how a system handles sudden increases or decreases in traffic. Like load and stress testing, spike testing can uncover weaknesses in autoscaling, caching, queueing, rate limits, and backend services.
Volume Testing
Volume testing evaluates how an application performs with large amounts of data. It is often used to test how the database responds when transaction volume, records, files, messages, or requests increase. This is useful for systems with high transaction volume, such as financial applications, booking systems, ecommerce platforms, and registration systems.
Endurance Testing
Endurance testing, also known as soak testing, measures how an application performs under load for an extended period, such as several hours or days. It helps identify issues such as memory leaks, resource exhaustion, connection pool problems, queue buildup, and slow degradation over time.
The type of performance test you run affects the load level, test duration, user scenarios, and reporting you need. To identify real bottlenecks and performance issues, the test workload should be as realistic as possible.
Who Does Performance Testing?
A performance test engineer is usually responsible for planning and executing performance tests. They use performance testing tools, either on-premises or cloud-based, to simulate user activity, collect results, and identify bottlenecks. They may work with developers, QA teams, DevOps, infrastructure teams, and product owners to fix bugs, tune systems, and improve performance based on test results.
What Is Performance Engineering?
Performance engineering is the discipline of applying performance-focused practices throughout the Software Development Life Cycle (SDLC). Instead of waiting until the end of development to test performance, performance engineering considers performance during requirements, architecture, design, development, testing, deployment, and monitoring.
Performance engineering includes architecture decisions, UI and UX considerations, code structure, database design, caching strategy, API design, infrastructure planning, monitoring, and business use case analysis. The goal is to build systems that are fast, scalable, reliable, and efficient from the beginning.
Performance engineering turns performance into an ongoing practice instead of a one-time test. It helps teams identify stage-specific risks early and design systems that can meet user expectations and business requirements under real-world conditions.
Who Does Performance Engineering?
A performance engineer helps define performance standards, review architecture, analyze bottlenecks, profile code, optimize databases, forecast demand, tune systems, and validate performance throughout the SDLC. They often work closely with developers, architects, QA, DevOps, SREs, and business stakeholders.
Performance Testing vs. Performance Engineering
Performance testing and performance engineering are closely related, but they serve different purposes. Performance testing measures how a system behaves under specific conditions. Performance engineering focuses on why the system behaves that way and how to design, build, and improve it for better performance.
For example, a performance test engineer may identify that checkout response time increases when traffic reaches a certain level. A performance engineer may investigate why that happens, such as a slow database query, inefficient API call, overloaded payment integration, poor caching, or connection pool limit, and then recommend changes to prevent the problem.
Here are some key differences:
- Performance testing involves designing and executing tests to determine website, application, or API performance. Performance engineering involves applying performance practices throughout the SDLC to build a higher-performing system.
- Performance testing uncovers bottlenecks and provides reports for analysis. Performance engineering uses those findings, along with architecture and code-level analysis, to help teams meet business and technical performance requirements.
- Performance testing focuses on whether the system can handle a given level of load while meeting baseline performance goals. Performance engineering focuses on designing systems that are fast, scalable, sustainable, and easier to optimize over time.
- Performance testing can often be performed with cloud-based tools and minimal coding. Performance engineering usually requires deeper technical knowledge of code, architecture, databases, infrastructure, monitoring, and system behavior.
Which One Should You Choose?
Performance testing is essential for confirming that websites, applications, and APIs can handle expected load. Performance engineering helps teams go further by designing and improving systems with performance in mind throughout development.
In practice, most organizations benefit from both. Performance testing validates current behavior. Performance engineering helps prevent performance problems from being designed into the system in the first place. Used together, they can reduce production issues, shorten QA cycles, and improve the user experience.
Using LoadView to Improve Website and Application Performance
LoadView is a cloud-based load testing platform for websites, applications, streaming media, and third-party web services. It can help teams measure performance metrics such as response time, breaking points, throughput, browser performance, and transaction behavior under load. LoadView uses real browsers and can run tests from multiple locations to simulate realistic user traffic and generate actionable performance reports.
LoadView also does not require coding experience for many browser-based test cases. Teams can create user scenarios with the point-and-click EveryStep Web Recorder.
Performance test engineers can use LoadView to measure performance, identify bottlenecks, and share results with development and infrastructure teams. Performance engineers can use LoadView across SDLC stages to validate how architecture, code, infrastructure, and user workflows behave under different load conditions. When LoadView results are reviewed alongside APM, logs, infrastructure metrics, and database monitoring, teams can better identify root causes and verify improvements.
Conclusion: Performance Testing vs. Performance Engineering
Performance testing and performance engineering both help teams build faster, more reliable websites and applications. Performance testing measures whether a system can meet performance expectations under specific conditions. Performance engineering helps teams design, build, and tune systems so they are more likely to meet those expectations in the first place.
Performance testing is often used before launch, before major releases, and during production readiness checks. Performance engineering is built into the SDLC and helps teams make better decisions about architecture, code, infrastructure, monitoring, and scalability.
LoadView can support both efforts by helping performance test engineers and performance engineers validate user journeys, APIs, and application behavior under realistic load before users are affected.
Ready to test your website, application, or API for performance? Sign up for the LoadView free trial today. Or sign up for a demo where one of our performance engineers can take you through the platform.