TestNG vs SpecFlow comparison of testing frameworks
What are the differences between TestNG and SpecFlow?

	TestNG https://testng.org/doc/documentation-main.html	SpecFlow https://specflow.org/
Programming language	Java	.NET
Category	Unit Testing, Intergration Testing, End-to-End Testing	Acceptance Testing
General info	TestNG is a testing framework for the Java programming language inspired by JUnit and NUnit TestNG is similar to JUnit and NUnit but with newer functionalities such as: annotations, test that your code is multithread safe, flexible test configuration, support for data-driven testing (with @DataProvider), support for parameters, powerful execution model (no more TestSuite) and more... It's also designed to cover all categories of tests unit, functional, end-to-end, intergration... etc	SpecFlow is a test automation solution for .NET SpecFlow is a test automation solution for .NET which follows the BDD paradigm, and is part of the Cucumber family. SpecFlow tests are written with Gherkin, using the official Gherkin parser which allows you to write test cases using natural languages and supports over 70 languages.
xUnit Set of frameworks originating from SUnit (Smalltalk's testing framework). They share similar structure and functionality.	No	No
Client-side Allows testing code execution on the client, such as a web browser	Yes The scope of testing with testNg is wide and you can test various front-end functionalities and behaviours with it	Yes Front-end behaviour is tested. With specflow specifications of the expected behaviours are made and specflow tests against this
Server-side Allows testing the bahovior of a server-side code	Yes You can test server-side functionalities and behaviours with TestNg	Yes Back-end behaviour is tested. Specifications of the expected behaviours are made and specflow tests against them
Fixtures Allows defining a fixed, specific states of data (fixtures) that are test-local. This ensures specific environment for a single test	Yes Fixtures are inbuilt into testNG, these are the annotations which are: @BeforeSuite, @AfterSuite, @BeforeTest, @AfterTest, @BeforeGroups, @AfterGroups, @BeforeClass, @AfterClass, @BeforeMethod, @AfterMethod	Yes BeforeTestRun and AfterTestRun are executed once for each thread which is a limitation of the current architecture.
Group fixtures Allows defining a fixed, specific states of data for a group of tests (group-fixtures). This ensures specific environment for a given group of tests.	Yes You can use various fixtures to setup environments for group tests	N/A
Generators Supports data generators for tests. Data generators generate input data for test. The test is then run for each input data produced in this way.	N/A	Yes SpecFlow contains a generator component. The SpecFlow IDE integration tries to locate the generator component in your project structure, in order to use the generator version matching the SpecFlow runtime in your project
Licence Licence type governing the use and redistribution of the software	Apache License 2.0	BSD license
Mocks Mocks are objects that simulate the behavior of real objects. Using mocks allows testing some part of the code in isolation (with other parts mocked when needed)	Yes By Use of an external library like mockit which intergrates well with testNG	Yes Specflow intergrates well with mock to give it excellent mocking capabilities
Grouping Allows organizing tests in groups	Yes Multiple test cases can be grouped more easily by converting them into testng.xml file, in which you can make priorities which test case should be executed first	Yes You can create test suites with specflow
Other Other useful information about the testing framework