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API test automation

API test automation in Katalon Studio

Import your OpenAPI, Postman, or WSDL definitions, verify every response, and run the same API suite in CI, alongside your web and mobile tests.

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  • REST, SOAP, and GraphQL
  • OpenAPI, Postman, and WSDL import
  • RESTGET, POST, PUT, PATCH, DELETE
  • SOAPSOAP and SOAP 1.2, from WSDL
  • GraphQLQueries and mutations in the body
  • OpenAPIImport Swagger 2.0 and OpenAPI 3.0

Trusted by 30,000+ quality teams

4.4 on G2 · 227 reviews
Why API tests fall behind

API tests only help if they run on every build

API checks wait for someone to click Send

Requests sit in a collection that someone runs by hand before a release. Nothing runs on its own, and nothing fails a build.

With Katalon Studio

Turn requests into test cases with verifications, group them into suites, and run them from CI on every build.

Only developers can change the framework

A hand-built framework needs Java and a build tool to change one assertion, so testers wait on developers.

With Katalon Studio

Testers add checks in the request editor and the manual view. Engineers script in Groovy or Java in the same project.

API and UI results live in separate reports

API checks run in one tool and UI tests in another, so nobody sees one picture of a release.

With Katalon Studio

Mix API, web, and mobile steps in one test case, and see every run in one TestOps record.

Capabilities

Everything an API test needs, in one tool

Build requests, verify responses, drive them with data, and run them in CI, next to the rest of your tests.

Every API style

REST, SOAP, and GraphQL in one editor

Set parameters, headers, body, and authorization in the request editor, send the request, and read the response without leaving Studio. GraphQL queries go in the request body.

Import

Start from the specs you have

Import API definitions as ready-to-send requests, or generate positive, negative, and edge-case tests from an OpenAPI spec with AI (beta).

  • OASOpenAPI 3.0 and Swagger 2.0
  • PMPostman collections (v2.1)
  • WSDLSOAP services
  • SoapUISoapUI projects
Verification

Assert on every response

Check status codes, headers, JSON and XML values, and schemas with built-in keywords, or write your own assertions in Groovy.

Hybrid tests

API, web, and mobile steps in one test case

Create an order through the API, then check it in the browser or the app, in the same test case and the same report. Set up test data through the API instead of clicking through the UI.

  • APIWS keywords to send and verify
  • WebWebUI keywords to check the page
  • MobileMobile keywords for iOS and Android
  • DesktopWindows keywords for desktop apps
Data-driven

One test, every data set

Bind CSV, Excel, or database data to a test suite and run the same requests for every row. Execution profiles switch base URLs and credentials per environment.

CI and reporting

Run in CI, report in one place

Run API suites headless with Katalon Runtime Engine in any CI system. Each run produces HTML, CSV, PDF, and JUnit reports, and results upload to TestOps.

How it works

From request to pipeline in three steps

Pick a pattern. Each snippet is the Groovy view of a Studio test case, so you can paste it in or build the same steps without code.

  1. 01Import or build requestsImport an OpenAPI, Postman, or WSDL definition, build a request in the editor, or generate tests from a spec with AI (beta).
  2. 02Add verificationsAdd checks from the verification snippets, use keywords in the manual view, or script assertions in Groovy.
  3. 03Run it everywhereBind test data, pick an execution profile, and run the suite in Studio or headless in CI with KRE.
Test Cases/Transfers/Create transfer.groovy
import static com.kms.katalon.core.testobject.ObjectRepository.findTestObject
import com.kms.katalon.core.webservice.keyword.WSBuiltInKeywords as WS

def response = WS.sendRequest(findTestObject('Object Repository/Transfers/POST create transfer',
        [('amount') : 250.00, ('currency') : 'USD']))

WS.verifyResponseStatusCode(response, 201)
WS.verifyElementPropertyValue(response, 'currency', 'USD')
Send a saved request with parameters, then check the status code and a JSON property.Verification snippets
Run the same suite with
  • Jenkins
  • GitHub Actions
  • Azure DevOps
  • GitLab CI
  • Docker
Explore Katalon Runtime Engine
Switching to Katalon

Keep what works.
Add what is missing.

Most teams already have API requests in a client tool or a code framework. Studio picks up from there instead of starting over.

Coming from Postman

Bring your collections with you

Import Postman collections into the Object Repository as ready-to-send requests, then add checks, test data, and suites around them.

Collections in Postman v2.1 format, plus environment filesVerification snippets for status codes, values, and schemasSuites that run in CI with Katalon Runtime Engine
Import from Postman
Coming from a code framework

Keep the code, add the rest of the team

Engineers keep scripting in Groovy or Java with full IDE support. Testers work in the manual view on the same test cases, so nobody waits on anyone.

Full-code, low-code, and no-code in one projectUse Java libraries and custom keywordsGit integration for reviews and branches
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Customer stories

Teams that test their APIs with Katalon

From fintech lending to telecom, QA teams cover APIs and UI in one framework.

60%less time creating test scripts

Tunaiku automated API and GUI tests with minimal configuration and runs them in CI with Jenkins and Docker.

Read the story
Testing with Katalon Studio is truly easy to set up. It provides out-of-the-box integrations with other CI tools (Jenkins) to support our CI testing goal. We can custom test with TDD, BDD, DDT, and more.
Dhicy RamdhaniQA Engineer, Tunaiku
One platform

API testing is part of Studio, one of four products
that form Katalon True

Test management, test automation, test execution, and production insights, all unified in Katalon True, the AI platform for software quality.

You are hereTest automationKatalon StudioAutomate web, mobile, API, and desktop tests fast, at any skill level: no-code, low-code, full-code, or with AI.On this page
Test managementKatalon TestOpsManage manual and automated testing in one record, with AI that runs your test cases and captures the evidence.Explore Katalon TestOpsTest executionTestCloud and KRERun tests in parallel across thousands of real browsers, devices, and OS combinations in the cloud, or on your own infrastructure.Explore TestCloudProduction insightsTrueTestMonitor quality in production from your own users' perspective, and turn real usage into real coverage.Explore TrueTest
View plans
Learn API testing

Jump in and learn more

ImageCourse

API Testing With Katalon: The Basics

A free Katalon Academy course: build requests, add verifications, and run your first API suite.Start free courseImageGuide

What is API testing?

How APIs work, the types of API testing, examples, and how to pick a tool.Read the guideImageComparison

Katalon vs Postman for QA teams

Where each tool fits, and when teams use them together.Read the comparison
Get started

Put your API tests on every build.

Start a free trial of Katalon Studio, import an OpenAPI, Postman, or WSDL definition, and send your first verified request today.

Start free trialTalk to experts
REST, SOAP, and GraphQLAPI, web, mobile, and desktopAny CI system
Questions

Frequently asked questions

What is API test automation?

API test automation sends requests to an API and checks the responses with code or a tool instead of by hand: status codes, response values, schemas, and response times. The tests run on every build, so a broken endpoint fails the pipeline before it reaches users.

Which API types does Katalon Studio support?

Katalon Studio tests REST APIs (GET, POST, PUT, PATCH, DELETE, and more) and SOAP services (SOAP and SOAP 1.2). GraphQL queries are sent as the body of a REST request, over GET or POST, and mutations over POST.

Can I import my existing API definitions?

Yes. Studio imports OpenAPI 3.0 and Swagger 2.0 files or URLs, Postman collections in v2.1 format, WSDL services, and SoapUI projects. Imported requests land in the Object Repository, ready to send and verify.

How do I verify API responses in Katalon?

Use the verification snippets in the request editor, built-in keywords such as WS.verifyResponseStatusCode and WS.verifyElementPropertyValue, or your own Groovy assertions. Studio also validates JSON and XML responses against a schema, and checks responses against an OpenAPI specification.

Which authorization methods are supported?

The request editor supports Basic, Bearer, Digest, NTLM, OAuth 2.0, and AWS Signature. API collections let a folder of requests share one authorization setting.

Can Katalon generate API tests with AI?

Yes, in beta. Point Studio at an OpenAPI or Swagger specification and it generates positive, negative, security, and edge-case test cases that you review and keep in your project.

How do I run API tests in a CI/CD pipeline?

Run the test suite headless with Katalon Runtime Engine using the katalonc command, with -browserType="Web Service". It works in Jenkins, GitHub Actions, Azure DevOps, GitLab CI, Docker, and other CI systems, and results can upload to Katalon TestOps.

Is Katalon a good alternative to Postman for API testing?

Many teams use both: Postman to explore an API, and Studio to turn those requests into maintained, data-driven test suites that run in CI and share reports with web and mobile tests. You can import Postman collections directly into Studio.

Get an AI summary of Katalon API testing

The Next Evolution of Manual Testing: Introducing Katalon AI Test Runner

Introducing Katalon AI Test Runner. Watch it run manual test cases live, with evidence for every pass and fail.

Live webinar
9:00 to 10:00 AM EST · Live online
Alex MartinsVP of Strategy
Gia EspositoSenior Solutions Engineer
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