The HTTP Archive format, or HAR, is a JSON-formatted archive file format for logging of a web browser’s interaction with a site. Browsers like Firefox or Chrome can export HAR files form the network monitoring tab in the developer tools.
On the other hand, Postman is a testing API client tool, allowing us to test a request against a specific environment. The tool includes the posibility of coding assertions on the response in order to check the correct behaviour of an API.
Har2Postman is a library. That means you can use it in any project that you think it might be useful. Just for demo purposes, you can find a converter below in this same page.