A program or service for data search based on certain rules. The parser processes information according to specified criteria and outputs it in a structured form. The input can take the form of a key phrase or any sequence of characters, as well as object characteristics, such as type, file size, or geolocation.

Unlike with an API, parsing does not involve securing permission from the owner of the donor resource to use the data. As a result, there are often legal issues around content obtained with a parser.

In the field of information security, parsers are used to analyze logs and search for traces of malware activity.