17 November 2023
10 Min. Read
API Testing Tools
Top 10 API Testing Tools in 2024
Key Highlights
In this blog, we cover the following key highlights
Modern software relies heavily on APIs, making their robustness crucial for success.
As APIs continually evolve, understanding and overcoming the challenges they present is essential for effective testing.
Prioritize automated API testing and harness appropriate tools to streamline the process.
Assess and choose the most suitable API testing tool for your specific industry.
In an era where software applications are increasingly interconnected, the role of APIs has become pivotal. APIs are the backbone of modern software, facilitating communication between different software components. Therefore, ensuring their robustness and reliability through effective testing is crucial.
At HyperTest, we were curious about the variety of API testing tools available today. To satisfy our curiosity, we decided to compare the top 10 performers. This blog post focuses entirely on our comparison criteria and the discoveries we made. But before we get into the details, let's set the stage.
What is an API?
Simply put, the way two or more computer programs’ communicate with each other is called Application Programming Interface i.e. API.
The term 'Application' refers to any software with a specific function, while 'Interface' can be conceptualized as a service agreement between two applications.
Example of APIs
Let’s understand APIs with the help of some examples. There are abundant of APIs in various domains. Here are a few:
Web APIs: These are used to enable communication between web servers and clients. For instance, the Twitter API allows developers to access and interact with Twitter's features, such as retrieving tweets or posting new ones.
Operating System APIs: These provide an interface for applications to interact with the underlying operating system. The Windows API, for instance, allows software to access various functionalities of the Windows operating system, like creating windows, managing files, and controlling hardware devices.
Database APIs: These allow applications to communicate with databases. The Java Database Connectivity (JDBC) API enables Java applications to interact with various databases using a standardized interface.
Library APIs: Programming libraries often come with APIs that provide predefined functions and classes. The Python Standard Library, for example, offers various modules with APIs for tasks like file handling, networking, and data manipulation.
Remote APIs: These enable remote control of devices or services. The remote API of a smart home system might allow a mobile app to control lights, thermostats, and security cameras from a distance.
Third-Party APIs: Many companies offer APIs to allow developers to integrate their services into other applications. The Google Maps API lets developers embed interactive maps into their websites or apps.
In essence, APIs are the bridges that enable software components to collaborate and work together seamlessly, enhancing the capabilities and functionalities of applications across different domains.
What is API testing?
API testing involves verifying that the application's functionalities operate as intended.
API testing, an integral part of software quality assurance, involves testing APIs to verify their functionality, reliability, performance, and security. Unlike traditional GUI testing, API testing focuses on the business logic layer of the software architecture. This type of testing is crucial as it helps detect issues early in the development cycle, leading to more stable and reliable software applications.
Read more - What is API Testing? A Complete Guide
Benefits of API testing
Finding bugs at an early stage of software development : Having access to the application without a user interface or users to engage with the system is a significant advantage of API testing. It provides QA engineers with early visibility into flaws and faults, enabling developers to address them before any impact on the interface occurs.
Optimizing Time Efficiency & Reducing Testing Expenses: API testing stands out for its rapid result delivery, leading to early detection of flaws and ultimately lowering overall testing costs.
Language Independence: Utilizing XML or JSON for data communication in API tests ensures language independence. This flexibility allows automation of API testing in the application using any core programming language.
Enhanced Test Coverage: Automated API tests go beyond the limited scope of unit tests, which concentrate on individual components, functions, or methods within the source code.
Issues often arise at the intersection of two modules, where one level's scope concludes, and another level begins.
API level testing is designed to validate the proper functioning of each system component, thereby improving the overall quality of the software and its interactions with users.
Challenges in API Testing
API testing, while essential, presents unique challenges that can impact the efficiency and effectiveness of your software testing process. Understanding these challenges is key to selecting the right tools and strategies.
Understanding API Specifications: APIs can be complex, with intricate specifications and rules. Testers must thoroughly understand these specifications to ensure comprehensive testing. This includes grasping various request and response formats, HTTP methods, and error codes.
Handling Diverse API Standards: With the existence of multiple API architectures like REST, SOAP, GraphQL, and others, a testing tool must be versatile enough to handle these varied formats. Each type of API has its own set of protocols and data formats (like JSON, XML), adding to the testing complexity.
Data Validation: Ensuring the correctness of data returned by APIs is another challenge. This includes validating response data against expected data formats, schema, and values. Incorrect data can lead to application failures.
Environment and Configuration Management: Setting up different testing environments for various stages of development (like staging, production) and managing configurations for each can be complex and time-consuming.
Keeping Up with Changes: APIs are frequently updated. Keeping tests up-to-date with these changes, especially in a fast-paced agile environment, is challenging and requires tests to be easily modifiable and extensible.
Now that we have covered all the foundational knowledge to understand the tools better, let’s dive straight into exploring the best API testing tools.
10 Top API Testing Tools in 2024
We have covered both the free tools and the paid tools in the API testing category. The top 10 best performing API Testing tools to consider for 2024 are:
HyperTest
Postman
Katalon Platform
Google Apigee
Apache JMeter
Rest Assured
Karate DSL
SoapUI
Blazemeter
Rest Console
1. HyperTest
HyperTest is the preferred no code API testing platform for modern agile teams. It regresses all your APIs by auto-generating integration tests using your network traffic without asking teams to write a single line of code. Its powerful assertions makes it impossible for teams to miss catching a problem during testing.
👉 Try HyperTest Now
If you want to get to high double digit coverage in a few weeks without needing to write or maintain API tests, then HyperTest could be your go to tool. It has shown to cut regression time from days or weeks to a few hours for 100+ teams across financial services, ecommerce, SaaS, banking and other sectors. Set-up HyperTest in a few minutes to see it in action.
Backed up by dev teams from Nykaa, Porter, Yellow.ai, Urban Company etc, HyperTest makes it impossible for devs to introduce a breaking change that is not reported back to QA teams. It tests a user-flow, across the sequence of steps an actual user will take in using the application via its API calls. It detects every issue during testing in less than 10 mins, that other written tests would definitely miss.
1.1 Key Features:
Test Queues/Async flows and contracts for 3rd Party APIs
Test GraphQL, gRPC & REST APIs
Test message queues & 3rd party APIs
Automatic assertions
API coverage Reports
Integration with any CI/CD tool like Jenkins, Circle CI, GitLab etc
Automatic documentation of APIs and schemas
Performance testing of APIs
Pricing: Free for one service; Followed by flexible paid plans
2. Postman
Postman is an API development environment which is divided into three parts – Collections, Workspaces, and Built-in Tools. Postman collections enable you to execute requests, conduct testing and debugging, automate tests, create mocks, document, and monitor APIs. It will also allow you to share the collections, set permissions, and manage participation in multiple workspaces.
2.1. Key Features:
Although it requires some coding effort, it anyways helps in automated testing
Assists in exploratory testing
It is compatible with Swagger and RAML (RESTful API Modeling Language) formats.
It supports knowledge sharing within the team
Run, test, document, and monitoring features
2.2. Limitations:
Free Version Restrictions: Limited to basic API testing purposes.
Suitable for tasks like validating API responses, status codes, and contracts.
Performance Testing: Not equipped for performance testing.
Lacks necessary insights and metrics for performance analysis.
Code Reusability: Postman test scripts are challenging to repurpose.
Website: https://www.postman.com/
Pricing: Starting from $12/month
Know About - Postman Vs HyperTest - Which is More Powerful?
3. Katalon
Katalon Studio is an automation tool for API, Web, Desktop testing and Mobile testing. It offers straightforward deployment by consolidating all frameworks, ALM integrations, and plugins into a single package. The capability of combining UI and API/Web services for multiple environments (Windows, Mac OS, and Linux) is also a unique advantage of Katalon Studio among the top API tools.
3.1. Key Features:
Endorses REST, SOAP requests, and SSL client certificates
Incorporates AssertJ support for crafting fluent assertions in BDD style
Facilitates test import from Swagger (2.0 & 3.0), Postman, WSDL, and WADL
Enables API test data setup through UI testing
Applicable for both automated and exploratory testing
3.2. Limitations:
Free Version Limitations: Katalon operates as a proprietary tool with restricted features in its free version.
Limited Community Assistance: Due to a smaller user base, community support for Katalon is relatively limited.
Finding solutions for intricate scenarios can be challenging.
Absence of Scripting Language Support: Katalon lacks support for various scripting languages.
Website: https://katalon.com/
Pricing: Free and Flexible paid plans available
Know About - Katalon Alternatives and Competitors
4. Apigee
Apigee stands out as a versatile cross-cloud API testing solution, driven by JavaScript. Developers and testers can seamlessly access its functionalities through various editors. Tailored for the needs of robust and intricate digital businesses, Apigee excels in handling APIs with substantial data. Its capability to analyze API traffic, response times, and potential error rates makes it adept at swiftly identifying and addressing performance-compromising issues.
4.1. Key Features:
Facilitates monitoring, implementation, and extension of API designs
Utilizes a multi-step process driven by JavaScript
Identifies performance issues through the tracking of API traffic, error rates, and response times
Streamlines the creation of an API proxy based on open API specifications, deployable in the cloud
4.2. Limitations:
Apigee requires a significant amount of resources, leading to a high initial expense for deploying it on-premises.
Employing a container-based approach could streamline the installation and deployment process.
Website:https://cloud.google.com/apigee/docs/api-platform/get-started/what-apigee
Pricing: Free and paid plans available
5. JMeter
JMeter is a freely available software designed for load and performance testing of applications. Operating on a cross-platform basis and functioning at the protocol layer, it serves as a versatile tool for developers. Notably, JMeter can be employed as a unit-test tool for JDBC database connection testing. With a plugin-based architecture, it facilitates the generation of test data and supports a Command-line mode, particularly beneficial for Java-compatible operating systems.
5.1. Key Features:
Enable caching and offline playback of test results
Seamless integration with CSV files, allowing the team to swiftly generate unique parameter values for API tests
Integration of API tests into the CI pipeline facilitated through JMeter and Jenkins
Applicable for performance testing of both static and dynamic resources
5.2. Limitations:
User Interface Experience: JMeter's user interface is often reported as not being user-friendly, causing challenges during test script execution.
Memory Utilization: JMeter tends to use a significant amount of memory, leading to frequent performance issues when compared to alternative API automation tools.
Scripting Complexity: JMeter's scripting process for API testing is more intricate in comparison to other available API testing tools.
Website: https://jmeter.apache.org/
Pricing: Free
6. Rest Assured
REST Assured is a freely available, open-source Java library utilized for the testing and validation of RESTful APIs. It stands out for its user-friendly approach in Java settings, making it a popular option among developers and testers dealing with REST services.
6.1. Key Features:
Accommodates all the main HTTP methods like GET, POST, PUT, DELETE, facilitating interactions with a variety of API endpoints.
REST Assured enables predefined configurations for requests, including base URI, headers, query parameters, and authentication, which can be reused in various tests.
It offers the capability to examine various elements of API responses, such as status codes, headers, the body of the response, and timing.
Comes with inbuilt capabilities for managing JSON and XML responses, which are prevalent in today’s APIs.
6.2. Limitations:
Limited Support for SOAP APIs: Does not specifically cater to the testing of SOAP (Simple Object Access Protocol) APIs.
Java Proficiency Required: To use REST Assured effectively, a solid understanding of Java programming is necessary.
Website: https://rest-assured.io/
Pricing: Free
7. Karate DSL
Karate DSL, an open-source API testing framework, utilizes Behavior Driven Development (BDD) and Gherkin syntax for API test automation. This approach, distinct from other BDD tools like JBehave or Cucumber, provides pre-defined step definitions, enabling easy test creation, even for those with minimal coding experience.
7.1. Key Features:
Supports BDD Syntax
It is beginner-friendly as it requires minimal coding experience.
Integrates with the Gatling framework for performance checks.
Features multi-thread parallel execution.
7.2. Limitations:
Unique Scripting Language: May require learning new scripting syntax.
Limited IDE Support: Absence of IntelliSense support in integrated development environments.
Challenges in Error Troubleshooting: Identifying code errors can be complex
Website: https://www.karatelabs.io/
Pricing: Starts at $64/month
8. SoapUI
SoapUI, a prominent API testing solution, is favored by many businesses for its ability to adhere to specific protocols and functionality needs. It supports a wide range of features and is compatible with REST and SOAP APIs. SoapUI specializes in API performance, security testing, and mocking, ensuring efficient and secure API operations.
8.1. Key Features:
Evaluates API stability under high user loads.
It provides insightful metrics analysis for easy decision-making.
Generates test simulations and analyzes performance data.
Includes checks for SQL injection and cross-site scripting.
Mimics API service behaviors for thorough testing
8.2. Limitations:
Occasional Stability Issues: Some users report stability concerns, leading to crashes or erratic behavior during tests.
Steep Learning Curve: The interface and features can be challenging for beginners in API testing.
Reliance on WSDL for Web Services: SoapUI depends on Web Services Description Language (WSDL) for web service testing, which can be a limitation if WSDL files are not well-defined or available
Website: https://www.soapui.org/
Pricing: Available for free trial and then a yearly license purchase of $659
9. Blazemeter
BlazeMeter is an advanced API testing tool that offers a range of features to streamline and optimize the testing process. It's designed to cater to various testing needs, from performance testing to API monitoring and functional testing.
9.1. Key Features:
Comprehensive testing tools on a single platform.
AI-driven test data generation for improved accuracy.
Easy integration with IDEs.
World-class device lab for extensive functional testing.
Robust API testing and monitoring features.
9.2. Limitations:
Pricing may be higher for smaller teams or startups.
Steep learning curve: To effectively analyze BlazeMeter reports, users need to have a good understanding of the tool and its data.
Website: https://www.blazemeter.com/
Pricing: Free plan, followed by Pro and Contract-based plan.
10. Rest Console
This Chrome-based REST/HTTP Client tool is designed for users to easily design and test custom HTTP requests with any RESTful API service.
10.1. Key Features:
Users can easily craft POST or PUT bodies with raw input.
It features a user-friendly interface for modifying custom headers.
The tool simplifies the process of creating query parameters.
It's versatile for various authentication methods including Plain, Basic, and OAuth.
The latest version, Rest Console v4.0.2, includes numerous updates for an improved user experience and bug fixes, such as enhanced oAuth functionality, collapsible sections, clickable links in responses, and UI improvements.
10.2. Limitations:
User interface is somewhat outdated and has limited accessibility.
Still in the early stages of development.
Website: https://github.com/ahmadnassri/restconsole
Pricing: Free
The Only Tool You Need to Test Your APIs
Don't have much time? Get a snapshot of the best API testing tools with our quick comparison chart.
While these are some really great tools, HyperTest is the only API testing platform that requires no code. Moreover, it guarantees over 95% coverage of your application in less than 5 minutes. Its unique approach to API regression discovers every API error for developers before release.
If you’re building a software, you need to use HyperTest, it is by far the best API testing tool.
Learn about how HyperTest helped a FinTech App serving over half a million users to catch every critical bug before production.
Schedule a demo to understand how it can also help you to ship out bug-free products in minutes.