Mastering API Testing with Postman, SoapUI, and Advanced Rest Client: A Step-by-Step Guide for Learners

As a QA Automation Engineer, one of the most important tasks is to ensure that APIs are tested thoroughly and efficiently. In order to do this, there are several tools available that can help automate the testing process. In this article, we will discuss three popular tools for API testing: Postman, SoapUI, and Advanced Rest Client. We will go through their features, pros, and cons to help you decide which tool is the best for your testing needs.

1. Postman:

Postman is a popular tool for API testing that is widely used by developers and testers. It is a user-friendly tool that simplifies the process of testing, documenting, and sharing APIs. The tool offers many features that make it easy to test APIs, such as:

• Simple Interface: Postman’s interface is easy to use and navigate, making it easy to create requests, view responses, and debug issues.

• API Documentation: With Postman, you can easily create API documentation that can be shared with your team or clients.

• Collection Runner: The collection runner allows you to run multiple requests at once, making it easy to test different scenarios.

• Environment Variables: Postman allows you to use environment variables, making it easy to switch between different environments (e.g., development, staging, production).

Pros:

• Easy to use: Postman has a user-friendly interface that is easy to navigate.

• Supports multiple platforms: Postman is available for Windows, macOS, and Linux.

• Easy to share collections: Postman allows you to share collections with your team or clients, making collaboration easy.

Cons:

• Limited scripting options: Postman has limited scripting options compared to other tools.

• Performance issues with large collections: Postman can be slow when working with large collections.

Know more about HTTP Protocol

2. SoapUI:

SoapUI is another popular tool for API testing. It is an open-source tool that allows you to test both REST and SOAP APIs. SoapUI is known for its robust feature set, which includes:

• Support for Multiple Protocols: SoapUI supports multiple protocols such as REST, SOAP, HTTP, JMS, AMF, and JDBC.

• Advanced Scripting: SoapUI provides advanced scripting options using Groovy, allowing testers to automate complex tests.

• Data-Driven Testing: SoapUI supports data-driven testing, allowing testers to test APIs with different data sets.

• Test Reporting: SoapUI provides detailed test reports, making it easy to analyze test results.

Pros:

• Robust feature set: SoapUI has a wide range of features that cater to different testing needs.

• Advanced scripting options: SoapUI provides advanced scripting options that allow testers to automate complex tests.

• Data-driven testing: SoapUI supports data-driven testing, which is essential when testing APIs with different data sets.

Cons:

• Steep learning curve: SoapUI has a steep learning curve, and it may take some time to get used to the tool.

• Slower Performance: SoapUI can be slower when working with large data sets.

3. Advanced Rest Client:

Advanced Rest Client is a simple yet powerful tool for API testing. It is a Google Chrome extension that allows you to test RESTful APIs. The tool offers many features that make it easy to test APIs, such as:

• Simple Interface: The interface of the Advanced Rest Client is simple and easy to navigate.

• HTTP Method Support: Advanced Rest Client supports all HTTP methods, making it easy to test APIs that use different methods.

• Request and Response Interception: Advanced Rest Client allows you to intercept both the request and response, making it easy to debug issues.

• Auto-Complete: Advanced Rest Client offers auto-complete functionality, making it easy to create requests.

Pros:

• Lightweight: Advanced Rest Client is a lightweight tool that does not require a lot of resources.

• Intercepts both request and response: This tool allows you to intercept both the request and response, making it easy to debug issues.

Cons:

• Limited to RESTful APIs: Advanced Rest Client only supports testing RESTful APIs.

• Limited scripting options: Advanced Rest Client does not offer advanced scripting options like SoapUI.

All three tools have their pros and cons, and the choice of tool depends on the testing needs and preferences of the QA Automation Engineer.

Postman is best suited for testers who require a simple tool with easy collaboration features, while SoapUI is more suitable for testers who require a robust set of features and advanced scripting options.

Advanced Rest Client is the best option for testers who want a lightweight and simple tool for testing RESTful APIs.

Ultimately, choosing the right tool for API testing can greatly improve the efficiency and effectiveness of the testing process. By understanding the features, pros, and cons of each tool, you can make an informed decision and choose the best tool for your testing needs.

Which tool is recommended for learners and why?

If you are a learner who is new to API testing, we recommend starting with Postman. Postman is a user-friendly tool that is easy to use and navigate, making it ideal for beginners who want to quickly learn and start testing APIs.

Here are some reasons why Postman is a great choice for beginners:

1. User-Friendly Interface: Postman has a simple and intuitive user interface that makes it easy for beginners to use and navigate. The tool allows you to create requests, view responses, and debug issues easily.
2. Easy Collaboration: Postman offers collaboration features that allow teams to work together on API testing projects. This makes it easy for beginners to learn from experienced testers and developers.
3. Comprehensive Documentation: Postman offers detailed documentation and tutorials on their website, making it easy for beginners to learn and get started with API testing.
4. Free Version: Postman offers a free version that provides access to most of the basic features required for API testing. This makes it easy for beginners to learn and start testing APIs without investing in expensive tools.

To download Postman, simply visit their website at https://www.postman.com/downloads/ and select the version that is compatible with your operating system. Postman is available for Windows, macOS, and Linux. Once you have downloaded and installed the tool, you can start exploring its features and functionality.

Postman is an excellent choice for beginners who want to learn and start testing APIs. Its user-friendly interface, collaboration features, comprehensive documentation, and free version make it an ideal tool for beginners. start API testing from basics

Find API Testing interview Q&A

Find the list of Free APIs for Beginner’s best practice using Postman:

1. JSONPlaceholder — This API provides mock data for testing and prototyping. It includes endpoints for posts, comments, albums, photos, todos, and users. You can access the API documentation here: https://jsonplaceholder.typicode.com/
2. OpenWeatherMap — This API provides weather data for any location on earth. You can use this API to get current weather data, forecast data, and historical data. You can access the API documentation here: https://openweathermap.org/api
3. REST Countries — This API provides information about countries, including their name, population, region, language, currency, and more. You can use this API to practice retrieving data and filtering data based on certain criteria. You can access the API documentation here: https://restcountries.com/
4. Random User Generator — This API generates random user data, including name, email, address, phone number, and more. You can use this API to practice retrieving data and working with JSON responses. You can access the API documentation here: https://randomuser.me/
5. Star Wars API — This API provides information about the Star Wars universe, including characters, films, planets, species, and more. You can use this API to practice retrieving data and working with nested data structures. You can access the API documentation here: https://swapi.dev/
6. RESTful Bookstore API — This API provides basic CRUD operations for managing books in a bookstore. You can use this API to practice making requests and testing basic API functionality. You can access the API documentation here: https://bookstore-app-backend.herokuapp.com/swagger-ui.html
7. Open Trivia DB — This API provides a simple trivia game, with questions and answers in various categories. You can use this API to practice making requests and retrieving data from a simple API. You can access the API documentation here: https://opentdb.com/api_config.php
8. Cat Facts API — This API provides random cat facts in JSON format. You can use this API to practice making requests and retrieving data from a simple API. You can access the API documentation here: https://cat-fact.herokuapp.com/#/

What is authorization-based APIs?

Authorization-based APIs are APIs that require some form of authentication or authorization to access certain endpoints or data. This means that users must provide some kind of credentials, such as a username and password, an API key, or a token, in order to access protected resources.

There are several types of authentication and authorization mechanisms that can be used with APIs, including:

1. Basic authentication — this mechanism uses a username and password to authenticate API requests.
2. Token-based authentication — this mechanism uses a token, such as an OAuth 2.0 token or a JSON Web Token (JWT), to authenticate API requests.
3. API key authentication — this mechanism uses an API key or access token to authenticate API requests.
4. Role-based access control — this mechanism defines roles and permissions for different types of users, and restricts access to certain endpoints or data based on those roles.

Authorization-based APIs are commonly used in web applications, mobile apps, and other software systems to protect sensitive data and ensure that only authorized users can access protected resources. Testing these APIs requires a good understanding of the authentication and authorization mechanisms used, and the ability to simulate different types of users and test different scenarios.

Here are few authorization-based APIs that you can use to practice testing authentication and authorization:

1. GitHub API — The GitHub API provides endpoints for managing repositories, issues, pull requests, and more. To use this API, you need to create a personal access token (PAT) in your GitHub account and include it in your API requests. You can use this API to practice testing authentication and authorization using OAuth 2.0. You can access the API documentation here: https://docs.github.com/en/rest
2. Auth0 API — Auth0 is an identity and access management platform that provides authentication and authorization services. The Auth0 API provides endpoints for managing users, roles, and permissions. To use this API, you need to create an Auth0 account and configure authentication and authorization settings. You can use this API to practice testing OAuth 2.0 authentication and authorization. You can access the API documentation here: https://auth0.com/docs/api
3. Stripe API — Stripe is a payment processing platform that provides APIs for managing payments, subscriptions, and customers. To use the Stripe API, you need to create a Stripe account and include your API keys in your API requests. You can use this API to practice testing authentication and authorization using API keys and OAuth 2.0. You can access the API documentation here: https://stripe.com/docs/api

These APIs provide real-world scenarios for testing authentication and authorization. By using Postman to make requests and test these APIs, you can gain valuable experience in testing authorization-based APIs.

Conclusion:

Mastering API testing with Postman, SoapUI, and Advanced Rest Client is a valuable skill for anyone looking to develop and test APIs. These tools offer a range of features and benefits that make testing APIs easier, faster, and more efficient.

By following a step-by-step guide and practicing with real-world APIs, learners can gain a better understanding of how APIs work, how to test them effectively, and how to troubleshoot issues that may arise.

Whether you are a beginner or an experienced developer, taking the time to learn and master these tools can help you improve the quality and reliability of your APIs.

So, if you’re interested in mastering API testing with Postman, SoapUI, and Advanced Rest Client, don’t hesitate to get started today. With the right tools, resources, and guidance, you can become a confident and skilled API tester in no time.

Thank you for sticking with this article until the end. If you enjoyed it, please leave a comment, share, and press that 👏 a few times (up to 50 times). It will help others discover this information, and maybe it will help someone else as well.

Follow me on Medium if you’re interested in more tutorials like this.