Knowing how to run load tests is an important aspect of programming and web development. However, understanding which type of load testing to implement is an even more important software design element. To get a better understanding of which is the best load testing type to use, we will first talk about what exactly load testing is and how it benefits web development.

Load Testing Types Explained – Load vs. UI vs. API

Load testing is a type of software testing that is meant to evaluate how an application or website performs under high traffic or workload conditions. An example of this would be placing a website or application under a stress test to see how much it can handle before crashing or slowing down significantly.

Tests like these are important for acquiring a clear view of how an application or website handles large numbers of users accessing it at once. Being aware of your application’s limitations can help you identify areas of improvement.

With this basic understanding of load testing, we can move on to discussing what exactly UI load testing and API load testing entails and how they differ.


UI Load Testing

UI load testing, also known as user interface load testing, is a type of front-end load testing designed to evaluate the performance of an implemented user interface of a website or application. The user interface, or UI, represents all the graphical and interactive aspects of an application or website that the user engages with.

UI aspects include buttons, menus, user-input forms, and any other visual and interactive elements. During UI load testing, the whole system is subjected to an extremely high volume of different user actions like clicks, inputs, and requests, to simulate real-world usage.

The results of this testing are a measurement of the response time and behavior of the application or website under an extremely heavy load to help identify areas of weakness that can be improved upon. Identifying these bottlenecks can help you avoid issues that impact the user experience of your application or website.


API Load Testing

API load testing, also known as Application Programming Interface load testing, is a type of back-end load testing that is designed to test the performance and scalability of the application API. The API is a collection of protocols, routines, and tools that software engineers utilize to build software applications.

The API is typically intended to enable communication between different software components or systems. During API load testing, the whole system is subjected to a wide range of high-volume requests, inputs, and data exchanges.

This simulated real-world usage will put a strain on the API with the goal of measuring the response time and behavior of the API under heavy loads. This will identify any areas of improvement that exist and highlight any bottlenecks or performance issues that may be occurring in the application.


Main Differences Between UI and API Load Testing

There are four key differences between UI and API load testing. These differences are the testing goals, testing process, knowledge set, and testing tools. The sections below will cover each of the differences in more detail.

  1. Load Testing Goals. The motivation behind UI and API load testing differs slightly. UI load testing is focused on evaluating the performance of an implemented user interface of an application or website. API load testing is more focused on gauging the performance and scalability of an application’s API.
  2. Load Testing Process. The load testing process is also different as UI load testing involves simulating user interactions such as clicks, inputs, and requests to measure response time and behavior. API load testing, on the other hand, involves simulating a high volume of different requests, inputs, and data exchanges through the API to evaluate response time and behavior under a heavy load.
  3. Load Testing Knowledge Set. The different skills and knowledge sets needed for proper UI and API load testing also varies. UI load testing requires in-depth knowledge of web development technologies like HTML, CSS, and JavaScript. Knowledge of relevant tools and frameworks is also required. API load testing requires a more focused understanding of web services and API testing tools and frameworks.
  4. Load Testing Tools. Both load testing types use different tools in their process. UI load testing uses tools and techniques like Selenium, Load View, JMeter, or LoadRunner. API load testing is typically performed using a different toolset including Postman and SoapUI, although JMeter and Load View can also be used.


How to Choose Between UI Load Testing and API Load Testing

Different circumstances call for varying load testing methods. Using the appropriate load-testing method will ensure that the application of the API being tested can be optimized to deliver a smoother and more responsive experience.

If the focus of the load testing is to optimize a web application’s graphical or interactive elements, then UI load testing is more appropriate. UI load testing is especially useful for testing the performance and scalability of web applications that emphasize user interaction.

E-commerce websites or social media platforms are examples of applications that can benefit from UI load testing. UI load testing should also be considered for use in the following situations:

  • Testing user interface performance under various loads and scenarios
  • Testing and improving the interactive elements of an application or website
  • Testing mobile applications under heavy loads


On the other hand, if the focus of load testing is to test the functionality and performance of an API, it makes sense that API load testing is the more appropriate method. API load testing will measure all elements of an application’s API and identify areas of weakness so they can be improved. API load testing should also be considered for use in the following situations:

  • Testing the performance and scalability of an application API.
  • Testing integration with payment gateways, social media platforms, or third-party data providers.
  • Testing and evaluating web application database operation efficiency.


UI & API Load Testing Tools

There are several different load testing tools available but two of the most popular are LoadView and JMeter. Both tools have their strengths and weaknesses in certain situations. LoadView is arguably the most popular load testing tool due to its accuracy, ease of use, and flexibility. LoadView has several key features that give it an advantage over JMeter including:

  • Browser Based Testing
  • User-Friendly Interface
  • Automatic Script Maintenance
  • Flexible Test Configuration
  • Scalability
  • Real-Time Monitoring
  • Easy Integration

LoadView uses real browsers to simulate user interactions, as opposed to JMeter, which uses HTTP/S requests to test APIs. Real browser-based testing Is widely regarded as more accurate and can help more efficiently identify bottlenecks that may be missed by standard API-level testing.

Using cloud-based load testing, LoadView features an extremely user-friendly interface that makes it easy for even non-technical users to create and run their own load tests. JMeter has a much steeper learning curve and technical knowledge to use effectively.

LoadView also provides automatic script maintenance, a flexible test configuration, and real-time analytics and reporting. This makes it much easier to use overall than JMeter, which requires more manual script maintenance.

Since LoadView is cloud-based, it can simulate thousands of different virtual users without requiring extra hardware. JMeter often requires the purchase of additional hardware to achieve the same level of scalability.

LoadView also easily integrates with other tools to automate and optimize the testing process. JMeter is also capable of this but typically requires more customization to achieve the same level of integration. Overall, LoadView is an extremely capable tool that has several advantages over JMeter. That being said, there are some circumstances where JMeter may be more appropriate.


UI Browser-Based Testing with LoadView

Browser-based testing is best done using LoadView. Browser-based testing includes testing web applications and websites in real browsers like Chrome or Edge. There are several situations where browser-based testing with LoadView is appropriate. These situations will be detailed below.


Testing Website Performance and Scalability

Browser-based testing is often used to test the performance and behavior of a website or web application under different load conditions. Different user interactions are simulated with a gradually increasing load and the maximum number of concurrent users the application can handle is identified. During this process response and load times are also measures and ways to improve identified.


Protocol-Based Testing with LoadView & JMeter

When doing protocol-based testing, JMeter is often the better solution. Protocol-based testing involves testing the specific performance and behavior of specific protocols like HTTP, HTTPS, FTP, SMTP, SNMP, TCP, AMQP, MQTT, RTMP, or JDBC.

During protocol-based testing, network traffic is simulated to measure response times and throughput. JMeter is more efficient at protocol-based testing and should be used in certain testing situations over LoadView. These situations will be detailed below.


Streaming Applications

Streaming applications can also benefit from Browser-based testing using a tool like LoadView. Video or audio streaming services can have their response times and throughput measured by simulating streaming traffic.

Some of the commonly used protocols when testing streaming applications are RTMP, RTP, and HLS. RTMP (Real-Time Messaging Protocol) is used for streaming audio, video, and data over the Internet. RTP (Real-Time Transport Protocol) is used for transporting audio and video over IP networks. Finally, HLS (HTTP Live Streaming) is used for streaming audio and video content over HTTP.


IoT Devices

Protocol-based testing can be used to test IoT (Internet of Things) devices and their communication protocols like Zigbee or Z-Wave. Device traffic is simulated and the response time is measured to identify performance issues and ensure that the devices can handle the expected load.

When testing IoT devices, there are several different protocols that are commonly used including MQTT, CoAP, HTTP, and ZigBee. MQTT (Message Queuing Telemetry Transport) is used to transmit small amounts of data between devices. CoAP (Constrained Application Protocol) is used when testing IoT devices that have limited resources, like low power or low memory.

HTTP is typically used to enable communication between IoT devices and cloud servers, while Zigbee is used in IoT devices for low-power and low-data rate communication.


Database Testing

Database systems can benefit from protocol-based testing using tools like JMeter. Behavior and performance under simulated database queries can be measured to identify performance issues and ensure the database can handle the expected load.

During database testing, there are several common protocols used. These include ODBC, JDBC, and SQL. ODBC (Open Database Connectivity) is a standard interface for accessing database management systems. JDBC is a Java-based API used to enable connectivity to relational databases.

SQL (Structured Query Language) is used to manage relational databases and send queries to measure response time. If a database does not use SQL, then there are other options to consider. For example, Cassandra uses CQL (Cassandra Query Language), MongoDB uses BSON (Binary JSON), and Redis uses its own proprietary protocol.


Wrapping It All Up: Final Thoughts on UP vs. API Load Testing

Now that you understand more about UI and API load-testing, you can clearly see the benefits of the LoadView testing tool. LoadView is packed with features that make load-testing easy and effective, even for non-technical users.

LoadView features Cloud-based SaaS solutions that require no infrastructure setup or maintenance, making it easy to scale and manage tests. It also offers a user-friendly interface that makes generating and accessing test results easy.

Even the more advanced features of LoadView such as geolocation testing, network emulation, and real user monitoring can be utilized easily by non-technical users. These features are critical for testing modern web applications and are not available in JMeter.

With competitive pricing based on actual usage, LoadView is also a more affordable load-testing tool than JMeter, making it the overall better option when considering tools for browser-based testing and even some protocol-based testing situations.