What Is Application Response Time & How to Reduce It

Introduction

How much do you know about your system's performance? Measuring response time can provide valuable insights and help you optimize your application. Slow response time can result in lost revenue and frustrated users. Explore the benefits of measuring response time and how it can help you keep your customers happy and engaged.

What is response time?

Response time is a software quality metric that measures the time it takes for a system to respond to a user request. It is an important metric because it directly impacts user experience and satisfaction.

When a user interacts with a software application, they expect a fast and responsive system. If the response time is slow, users can become frustrated and abandon the application. Therefore, it is important for development teams to measure and optimize response time.

The metric can also help identify performance bottlenecks in the system. However, measuring response time is connected with a set of risks: inaccurate measurements, insufficient context or false positives/negatives.

Benefits of having a short response time

Improved User Experience

Measuring response time helps identify areas of the application that are slow and need optimization. By optimizing these areas, the application responds faster and provides a better user experience.

Increased customer satisfaction

Faster response time leads to a more satisfying user experience. Happy customers are more likely to continue using the application and recommend it to others.

Better application performance

Measuring response time helps identify bottlenecks and areas for improvement in the application. Optimizing these areas leads to better performance and a more stable application.

Enhanced scalability

Measuring response time helps ensure the application can handle increased traffic and usage. Optimizing response time can increase the scalability of the application and reduce the need for costly infrastructure upgrades.

Competitive advantage

A fast and responsive application can provide a competitive advantage in the market. Measuring and optimizing response time can help ensure the application remains competitive and attractive to customers.

Risks connected to relying on response time

While measuring response time can provide valuable insights into application performance, there are also some potential risks to consider:

Overemphasizing response time

Focusing too much on response time can lead to neglecting other important aspects of software quality, such as security or maintainability.

Inaccurate measurements

Response time measurements can be influenced by factors outside of the application, such as network connectivity or user device performance. This can make it difficult to accurately identify and address performance issues within the application.

False positives/negatives

Response time measurements can sometimes produce false positives or negatives, meaning they may incorrectly identify performance issues or fail to detect actual issues.

Insufficient context

Response time measurements may not provide enough context to fully understand the root cause of performance issues. Additional monitoring and analysis may be necessary to gain a more complete understanding.

Cost and resource usage

Measuring response time can require additional resources and may come with associated costs. This can impact the overall development process and project budget.

Omitting user experience issues

One potential risk is that response time measurements do not necessarily reflect user experience. For example, an application may have a fast response time but still have usability issues that negatively impact user experience.

How to measure response time?

Response time is typically measured by tracking the time it takes for a user request to be processed and for a response to be returned. This can be done using tools such as performance testing software, application performance management (APM) tools, or server log analysis.

For example, a common way to measure response time is through load testing, where a simulated user load is applied to the system and the response times are recorded. Another way is to use APM tools that track application performance in real-time and provide metrics on response time, latency, and other performance indicators.

Example 1: e-commerce website

Let's take the example of an e-commerce website that sells products online. To measure the response time of the website, we can use a tool like Google Chrome's Developer Tools. Here's how:

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1. Open Google Chrome and go to your website.
2. Right-click anywhere on the page and select "Inspect" from the context menu.
3. In the Developer Tools panel that opens, click on the "Network" tab.
4. Reload the page by pressing the F5 key or clicking on the reload button.
5. The Network tab will display a list of all the requests made by the page, along with their status codes, sizes, and timings.
6. Look for the main HTML document of the page and click on it to see more details.
7. In the details pane, you'll see the "Timing" section, which includes the "Request Time" and "Response Time" values.
8. The response time is the time it took for the server to respond to the request and send the data back to the browser.

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Another way is to use Lighthouse, which provides those and additional measurements in a more user-friendly way.

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We can also use load testing tools like Apache JMeter, k6 with its browser module to simulate a large number of user requests and measure the response times under different loads. Also, there are interesting new ideas of using Cypress for load testing. This helps us identify performance bottlenecks and optimize the application for better response times.

Example 2: web application 

Let's take the example of a web application that provides weather information. In this application, users can enter a location and get the current weather conditions for that location.

To measure the response time of this application, we can use a tool like Pingdom or New Relic. Here's how:

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1. Sign up for a Pingdom or New Relic account and add your web application to be monitored.
2. Configure the monitoring tool to test the application's response time from different geographic locations and under different loads.
3. Monitor the application's response time over time and look for trends or anomalies.
4. For example, if the monitoring tool shows that the response time for the application is consistently slow for users in a particular geographic region, we can investigate whether the application's servers are located far away from that region and consider deploying servers closer to improve response times for those users. Similarly, if the monitoring tool shows that the response time degrades under high load, we can consider optimizing the application's database queries or caching mechanisms to handle the load more efficiently.

Example 3: mobile application

Let's take the example of a mobile app that allows users to book flights. In this app, users can search for flights, select a flight, and complete the booking process.

To measure the response time of this app, we can use a tool like Firebase Performance Monitoring or AppDynamics. Here's how:

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1. Sign up for a Firebase Performance Monitoring or AppDynamics account and integrate the SDK into your mobile app.
2. Configure the monitoring tool to track the app's response time for different user actions, such as searching for flights, selecting a flight, and completing a booking.
3. Monitor the app's response time over time and look for trends or anomalies.
4. For example, if the monitoring tool shows that the app's response time is slow when searching for flights, we can investigate whether the search algorithm is optimized and consider optimizing it further to improve response times. Similarly, if the monitoring tool shows that the app's response time is slow when completing a booking, we can investigate whether the booking process is streamlined and consider optimizing it further to improve response times.

Response time alternatives

Apdex

Apdex is a metric that measures user satisfaction based on the response time of an application. It takes into account the user's expectation of response time and defines a satisfaction threshold. Apdex measures the ratio of satisfied, tolerating, and frustrated user requests to determine an overall satisfaction score.

Error rate

Error rate measures the frequency of errors in an application. By measuring the number of errors in relation to the number of requests, you can identify areas of the application that need improvement. This metric is especially useful for detecting critical errors that can lead to data loss or application crashes.

Throughput

Throughput measures the number of requests processed by an application over a given period of time. This metric is useful for determining the capacity of an application and its ability to handle a high volume of requests.

Resource utilization

Resource utilization measures the use of resources such as CPU, memory, and disk space. By measuring the utilization of these resources, you can identify areas of an application that are inefficient or may cause performance issues.

Cyclomatic Complexity

This metric should be used during the development process to ensure that the codebase is maintainable and easy to modify. It can be used to identify areas of code that may be more difficult to test or debug, and to guide refactoring efforts to reduce complexity and improve code quality.

Summary

Measuring response times continuously allows you to identify and address performance bottlenecks, as well as potential issues before they become critical problems. However, it’s crucial to track and improve response times in a continuous way, e.g. after each change or before each release and not rely solely on that metric. That way you make sure that you address the right problems and constantly keep the finger on the pulse of your product’s quality.

The best way to succeed with continuous software quality improvement is to find your own set of metrics - perfectly fitted to the goals of your product. Which ones to choose? The answer awaits in other chapters of this handbook - explore other software quality metrics and compose a perfect set to start with.

Need help with your development efforts?

Our specialists can help you with selecting the right software development metrics and speeding up your development efforts. Feel free to contact us. If you're not sure what hiring option to choose, analyze which option will be more viable for you: inhouse or outsourcing.