Software testing: Software testing is process used to identify the correctness completeness and quality of the developed computer software. It includes a set of activities conducted with the intent of finding errors in software so that it could be corrected before product released to the end users. In simple words software testing is an activity to check whether actual results match the expected results and to ensure that software system is defect free. Software testing is more than just error detection, Testing software is operating the software under controlled conditions, to verify that it behaves as specified, detect errors, and validate that what has been specified is what the user actually wanted. Actually testing is the process of analyzing a software item to detect the differences between existing and required conditions (that is defects/errors/bugs) and to evaluate the features of the software item.

Software development: Software development used to refer to the activity of computer programming, which is the process of writing and maintaining the source code, but in a broader sense of the term it includes all that is involved between the conception of the desired software through to the final manifestation of the software, ideally in a planned and structured process.  Therefore, software development may include research, new development, prototyping, modification, reuse, re-engineering, maintenance, or any other activities that result in software products Software Developer has to deal with all actions from the initial design up to the final testing of software.

Difference: The process or phase of creating software is called software development, once the software has been created and ready to provide for end users, we test the software with the requirements.  Software testing is an execution of a program with the intention of finding bug.

Development is writing the code, testing is finding out whether or not the code runs the way you expect it to. Software testing is a scrutiny performed to provide information about the quality of a product or software under test to the concerned clients. The trained professionals who perform these testing jobs are called software testers. Software testing includes many different techniques and is not only limited to execution of programs to find errors or software bugs. Software development (also known as application development, software design, designing software, software application development, enterprise application development, or platform development) is the development of a software product.

Software tester works with the new software and help in repairing the errors occurred in it whereas Software developers are the professionals who develop the new software products depending on the client requirements. Software developers’ responsibilities also include broader aspects in development of software products. Software development comes with developer, software publisher, programmer and system development life cycle. Software testing is done by software testers, manager, test lead, test designer, tester, automation developer, and test administrator.