API Testing | What Is It & How Should You Perform It in 2024?

Are your APIs performing at their best? Today, over 83% of web traffic relies on API requests. This makes API testing more critical than ever. Without proper testing, poorly functioning APIs can cause system crashes, security breaches, and financial loss.

But how can you ensure top API performance? This blog breaks down what API testing is and why it’s essential. We’ll also explore the best tools for testing APIs.

Plus, you'll learn how to use Postman to test API requests easily. With these insights, you’ll be ready to keep your APIs running smoothly in 2024. Let's begin.

What is API Testing?

API testing is a process of verifying that application programming interfaces (APIs) meet functionality, reliability, performance, and security standards. Unlike traditional testing, which focuses on the user interface, API testing directly tests applications' business logic.

For example, when a payment gateway processes transactions, API testing ensures data flows correctly between systems.

According to SmartBear’s 2023 State of API report, 91% of organizations consider API testing critical to their strategy.

Popular tools like Postman and SoapUI allow developers to automate tests, ensuring seamless communication between services and detecting issues early, which is vital for successful software integration.

Why Should You Perform API Testing?

API testing is important for several reasons.

1) First, it confirms that APIs work as intended, ensuring they perform their tasks correctly.

2) It also helps identify security risks early, which protects sensitive data from hackers.

3) By testing, you can validate that the correct data is transferred between systems.

4) It’s also useful for enhancing performance by checking how APIs respond under different loads and conditions.

5) Another benefit is catching bugs early, which reduces the time and cost of fixes later.

6) Finally, consistent API testing leads to more reliable systems, improving the overall user experience and stability of the software.

Which Tools Allow You to Test Your APIs?

Several tools are available for API testing.

Postman is one of the most popular. It offers a user-friendly interface and strong testing features.

SoapUI is also widely used. It supports both REST and SOAP API testing.

Katalon Studio and RestAssured are great for automation. They easily integrate with CI/CD pipelines.

JMeter is ideal for testing API performance under heavy loads.

Each of these tools helps ensure API functionality, security, and performance. They are essential for modern software development and integration.

What is the Simplest Way to Test Your APIs?

The simplest way to test APIs is by using the Postman. Let's show you all the steps.

Testing API Requests via Postman

First, you'll need to create an account at your desired API website. For example, I will test the ipstack API by APILayer .

Click on the "Get Free API Key" button at the top right corner. You will then receive the form below.

Choose your desired plan. Fill out the form and click on the Sign-Up button given at the end of this form.

Next, click on the Login button next to the "Get Free API Key" button. You will see the login form below.

Enter your login credentials and click on the Login button. You will get the dashboard given below:

Our API key is in the dashboard section, as you can see. You can also reset the API key.

The next step is to create an account at the Postman.

Click on the Sign Up Free button at the top right corner. Postman is a free API testing tool. Create an account and you will see a screen as shown below:

In the top section, you can see "Search Postman". You should search for your API here if your chosen API has endpoints collection available at Postman. If it is not present in those search results, we will also guide you in testing those APIs in the coming section. For now, when I write Ipstack, I get the endpoints collection as shown below:

Click on "Ipstack" or select your desired API collection.

You will get a complete guide as shown below:

When you click on the endpoints collection in the left column of the Postman under the Ipstack, you will see a new interface where your endpoint will be added to the request bar, however, when you click on the Send button, you get a message to Fork the collection:

Click on Create a Fork, which will help you send API requests for testing. However, you still need the API key to run this request. When I click on Create a Fork button, I see the below interface:

Then, I again click on the Fork Collection button given at the bottom. I get the below interface. Next, click the "go to authorization" tab that appears when you bring an arrow at the end of the "access-key" row.

Again, you should click on the "Authorization" tab next to the "Overview" tab:

You will get the below form, and you have to insert the API key here:

Press "Ctrl + S" to save the changes and get back to your API endpoints. You will be able to see the API key added here in the form of the password dots:

Now, when you click on the "Send" button, you will see an API response. Otherwise, you will get an error if there is a problem with your API key. My API response is shown below:

Now, if your API is not found in the API collections of the Postman. There is still a way to test your API. In the home tab, click on My Workspace:

Next, you should click on the Plus button to create a new collection:

Choose the blank collection and name it:

When you right click on the New Collection in the left column, you will see the below options:

Choose "Add Request". You will see an interface like the one given below:

On the left side, choose the API request type from the dropdown. Right now, it is set to GET the request in green. Next, enter the API URL and the API key, as discussed in the earlier steps, and click on the Send button. That's it.

This was all about testing your APIs for free using the Postman free API testing tool.

Conclusion

API testing is essential for keeping your APIs performing at their best. It ensures system stability, security, and performance. Since over 83% of web traffic depends on APIs, regular testing is a must. Tools like Postman, SoapUI, and JMeter help automate tests and catch issues early.

This improves integration and workflow efficiency. Proper testing guarantees accurate data flow between systems. It also prevents security breaches. By using these tools and techniques, you can maintain reliable, secure, and high-performing APIs. This will keep your systems running smoothly in 2024 and beyond.

FAQs

How Can You Automate API Testing To Improve Efficiency In Continuous Integration Workflows?

You can automate API testing using tools like Postman to streamline continuous integration workflows.

What Are Some Common Types Of API Requests, And How Are They Used In Testing (E.G., GET, POST, PUT, DELETE)?

Common API request types include GET (retrieves data), POST (submits data), PUT (updates data), and DELETE (removes data). These requests test API functionality, data flow, and performance.

How Do You Ensure That Your API Tests Cover Edge Cases And Handle Unexpected Input Or Failures?

I ensure my API tests cover edge cases and handle unexpected input by designing comprehensive test scenarios, including boundary values, invalid data, and failure conditions, to evaluate the API's robustness.

How Do You Differentiate Between API Testing And Other Types Of Software Testing, Like UI Testing?

API testing focuses on verifying the functionality, reliability, and performance of the backend API directly, while UI testing evaluates the graphical interface's responsiveness, usability, and visual elements.