12 Best API Testing Tools for 2024

Posted On: 1 February 2024

API testing verifies the functionality, reliability, performance and security of API and ensures consistency in performance of web and mobile applications. API testing software allows development teams to test an application's essential functions proactively thus streamlining performance of applications. The following blog discusses features of top API testing tools –2024 and the importance of API test automation.

Review Of Top 12 API Testing Tools In The Industry

1. ACCELQ

ACCELQ provides continuous testing solutions for functional and API testing needs. It supports RESTful Web Services and Microservices and is available as both SaaS (software as a service) and on-premises models.

It has an analytic runtime engine with advanced multi-step heuristics that can detect changes to application elements and automatically adapt to ensure reliable test executions.
Provides 360-degree quality coverage by embedding critical server-side API validations alongside front-end testing. So, users can quickly verify response times, status, occurrence, header values, content, and more through a wizard-based approach.
The continuous action dashboard also provides an overview of the software development lifecycle (SDLC) status, allowing users to visualize failure density and patterns easily.

Features:

This platform integrates with DevOps tools like JIRA and Bamboo
ACCELQ performs API and UI (User Interface) Test Automation in the same simplified flow.
It directly correlates business processes and corresponding API for complete coverage.
The platform provides RESTful Web Services and Microservices.
The APIs (Application Programming Interfaces) need regression-level test automation maturity. ACCELQ ensures automated API testing including automated test design, codeless automation logic, complete test management, planning, and 360 tracking.

Website Link: https://www.accelq.com/

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2. Assertible

This is a popular AP testing tool among developers. Assertible automates API testing at every phase, from continuous integration to delivery pipelines.

Features:

It performs API test automation across the CI/CD pipeline.
It supports validating HTTP responses using turn-key assertions.
It comes with an encrypted variable feature for storing passwords, tokens, and confidential data fields.
Integrates with tools like GitHub, Zapier, Slack, and more.

3. API Fortress

API Fortress is an open-source tool for API testing and can automate performance and functional testing.

Features:

Plug-and-play functionality for simulating API testing.
Web-based API testing tool using which software testers can perform tests in any browser.
It supports microservices, web services, SOAP, and GraphQL.

4. Hoppscotch

This open-source API testing tool comes with a minimalist UI design and can generate API requests quickly.

Features:

Full-duplex communication using a single TCP connection
Data transmission and receiving using the SocketIQ server
This tool supports REST, GraphQL, and Realtime protocols.
REST and GraphQL protocols have environments, collections, and history features.
CreateS reusable variables in scripts and can help when managing shared data with a team.
Hoppscotch helps in organizing API requests with collections. Create collections and add requests to them to share with the team or to use later.
Helps track API requests and responses.

5. JMeter

Apache JMeter is an open-source Java application that tests performance and load of web applications. owever, it cannot perform all the actions supported by browsers, as it is not a browser but works at a protocol level.

Features:

JMeter is compatible with both static and dynamic resources for improving test performance.
Can load and perform testing in various applications/server/protocol types, namely SOAP / REST Web services, Java Objects, and more.
This API testing tool is compatible with languages like Groovy and BeanShell.
Data analysis and visualization plugins of this tool allow extensibility.
Functions can provide dynamic test inputs.
This tool integrates through third-party open-source libraries for Maven, Gradle, and Jenkins.

6. Katalon Studio

Katalon caters to a wide range of testing requirements such as web, API, mobile, desktop, AI visual, and enterprise applications.

Features:

Katalon supports REST-API testing, SOAP/1.1, and SOAP/1.2 requests.
Tests can be imported from Swagger, Postman, and WSDL.
This platform performs data-driven testing with multiple data sources (e.g., XLS, CSV) and databases.
Katalon also supports BDD testing with Cucumber files and a native Gherkin editor.
Enable CI and DevOps practices with built-in integrations. Easy deployment with Docker containers.
Local and remote execution with real-time analytics.

7. Karate DSL

This API testing software allows users to create scenarios for API-based tests by creating definition steps automatically to accelerate the API testing process.

Features:

Asynchronous support for WebSocket
Built on top of the Cucumber JVM
This tool creates test cases using a Gherkin-like BDD syntax.
Using a Java API, the tool can combine Java projects or legacy UI automation suites.

8. Postman

Postman helps in building and utilizing APIs and streamlines all phases of testing in the API lifecycle. It provides a range of automated API testing tools, workspaces, and integrations that simplify the development process.

Features:

Compatible with Google, Mac, Linux, and Windows systems.
The platform supports writing Boolean test cases (without a command line.)
Postman’s API Builder helps to implement an API design workflow through OpenAPI, GraphQL, or RAML specifications.
The Private API Network supports versioning to maintain control and manage multiple versions of APIs in the network.

9. Ready API

It is a popular functional testing tool allows testers to test SOAP and REST APIs and web services quickly.

Features:

It provides detailed end-to-end testing to chain together complex API transactions and workflows. It creates testing suites that can be run in a CI/CD environment.
With a click, ReadyAPI can add security scans to new or existing functional tests.
Import data from a file or database or create synthetic data easily with ReadyAPI Data Generator.
Synthetic data helps test new programs without actual user data in software testing.
ReadyAPI easily integrates with native plugins, other popular tools, and Command Line Interface.
Measure the test coverage of the entire API by importing OpenAPI Specification (fka Swagger) into ReadyAPI.

10. Rest Assured

Rest-Assured is an open-source Java tool designed to simplify the process of testing REST interfaces. It verifies complex HTTP responses within applications, supporting JSON and XML formats.

Features:

Behavior-driven development (BDD) that simplifies API testing in Java
Seamless integration with Serenity automation framework
Built-in functionalities so that users don’t have to create test cases from scratch
A single framework that combines REST services and UI

11. SoapUI

SoapUI is a versatile open-source API testing tool and is usually preferred for REST, SOAP, and GraphQL-based web service validation. With SoapUI, web services meet the required functionality, performance, and security standards across different protocols.

Features:

The tool has a drag-and-drop feature to create and run complex scenarios.
Using a complement of tests and scans, it protects the services on websites against the most common security risks.
Create load tests quickly and easily based on existing functional API tests.
This tool doesn’t require expensive full-scale replicas of your production systems.
This tool supports SOAP/WSD, REST, GraphQL, and JMS protocols.

12. Swagger

Swagger by SmartBear is a suite of API testing tools that facilitate the entire API development lifecycle, from design to deployment.

Features:

It allows teams to design API interfaces before writing code. Creating and testing the API structure ensures the requirements are met and are logically consistent before implementation.
It includes schema validation and can automatically ensure that the requests and responses of the API match the defined schema.
It maintains consistency and reliability in API responses and requests.

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Conclusion

Automating API testing enables early detection of bugs, increases test case reusability, and virtually rules out human error. It also facilitates quicker and more efficient development of API products, saving time and resources in the long run. ACCELQ's Automate API simplifies your testing process with features as follows -

It uses a popular test automation framework to minimize scripting requirements.
ACCELQ’s data-driven framework updates test logic instead of test data for application testing. As a result, the platform that implements the framework enables adaptation to changes.
The platform has a built-in CI workflow that initiates an automated regression of the API suite.
It conducts regression testing based on requirements tracking automating API test suite analysis.

Choosing the best API testing tool is paramount to handle software development complexities as businesses grow. Schedule a free demo to understand why ACCELQ is ideal to automate API testing.

Geosley Andrades

Director, Product Evangelist at ACCELQ

Geosley is a Test Automation Evangelist and Community builder at ACCELQ. Being passionate about continuous learning, Geosley helps ACCELQ with innovative solutions to transform test automation to be simpler, more reliable, and sustainable for the real world.