File-format fuzzing is generally used in those cases where a program is importing/exporting data streams in and out of files. To perform file-format fuzzing, you have to generate multiple input seeds with different file formats and save them in a single file. The fuzzer will then use the saved file as an input to the server/application, recording any kind of crash that may occur. We will now move on to the next section, which will introduce us to web app fuzzing.