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API testing

Postman API Testing vs Tricentis API Scan: What’s the Difference?

Testers getting started with API testing quickly realize the importance of synchronizing their API testing work with developers’ API testing efforts. It all boils down to the common expression: Why reinvent the wheel?

If a development team is working on APIs, you can guarantee that the developers are performing at least some testing on each method/ operation before they declare the related user story “done” and ready for QA. Why not capture the developers’ work as building blocks that testers can reuse and extend?

There are multiple ways to do this in Tricentis Tosca: you can capture developers’ work in well-known developer tools such as Postman and SoapUI, or you can give developers access to the Tricentis API Scan tool that was built specifically to facilitate developer<>tester collaboration.

There’s been a lot of interest in our new Postman API test importer tool—specifically about how it compares to Tricentis API Scan. Here are answers to the most common questions…

What is Postman?

Postman is an API tool that helps developers create, share, document and test APIs. It is available in free, pro, and enterprise editions. Postman offers functionality for designing and mocking, debugging, test automation, documentation, API monitoring, and publishing. For details and downloads, see the Postman site.

Tricentis  provides a Postman API test importer that brings Postman project artifacts into Tricentis Tosca.

What is API Scan?

Tricentis API Scan is a free, lightweight tool that accelerates API testing by helping team members reuse and build upon each others’ API testing efforts. Developers can use API Scan to check that their APIs work as expected.  As developers exercise APIs with API Scan, key test details (e.g., authentication and appropriate request parameters) are saved for reuse across the team. Developers gain a fast and intuitive way to check their work—and at the same time jumpstart QA’s API testing efforts. For details and downloads, see the API Scan Tricentis Marketplace page.

How Do API Scan and the Postman Importer Compare for API Testing?

Let’s compare the two API testing tools in terms of API technology support, API test creation, API regression testing, and Tricentis Tosca integration.

API Technology Support

API Scan supports a full stack of technologies like REST, SOAP, JMS, SAP RFC, OData, IDOCs, HL7, Oracle SB, IBM MQ, Tibco EMS and more (see the Tricentis API Testing page for a detailed list). Postman supports HTTP and REST only.

API Test Creation

Postman can create tests from RAML, WADL, and Swagger.   API Scan can create tests from WSDL, XSD, Swagger, OData Definition, RAML, WADL, and JSON Schema—with easier to read example and value creation results than Postman (see the screenshots below).


Tricentis API Scan

API Scan can also create tests and service virtualization assets by recording HTTP traffic via system proxy (like Fiddler does).  It can record any HTTP traffic—which means you can record traffic from a mobile or desktop app, Slack, or a chatbot, for instance. Postman supports HTTP recording with Chrome extensions only.

*If you’re new to the concept of HTTP recording, it’s a great way to quickly create tests—even if you don’t have a service definition or sample messages. It simply “sniffs” and captures the HTTP traffic that passes between the application and the API. API Scan makes it simple to get started with HTTP recording. You can immediately record any HTTP traffic without reconfiguring the application or standing up complex proxies.

API Regression Testing

Postman performs regression testing. API Scan is focused exclusively on helping developers scan APIs, so it does not address regression testing. For regression testing, teams import their API Scan tests into Tricentis Tosca, which provides the industry’s leading regression testing capabilities for APIs, web, SAP, mobile, mainframes, and more (see the Gartner MQ for Software Test Automation and Forrester Wave for Omnichannel Test Automation).


Tricentis Tosca Integration

Postman collections can be automatically imported into Tricentis Tosca API tests that are model–based and business-readable—simplifying test case maintenance and extension. These tests can be reviewed, adjusted, and extended into end-to-end tests, parameterized with Tricentis test data management, and executed alongside other Tricentis tests during your CI regression testing. The same test cases can also be converted into service virtualization assets, which simulate service behavior so you can test the front end earlier, more consistently, and more thoroughly.

Tricentis API Scan tests are automatically converted into Tricentis Tosca API tests when you bring them into Tricentis Tosca. Since API Scan is optimized for Tricentis Tosca test creation, minimal to no test review and adjustment is needed after tests are imported. Of course, tests from API Scan can be easily extended, parameterized, and used for service virtualization— just like the imported Postman tests can.


Hope that helps. If you have additional questions, or you’d like to learn more about API testing, contact us or watch this great presentation from Robert Wagner, Tricentis Product Manager for API Testing and Service Virtualization, at Accelerate 2018.