BeautifulSoup

BeautifulSoup is a Python library for parsing HTML and XML documents. It creates a parse tree from page source that can be navigated and searched. It is designed for quick extraction of data from malformed markup and for operations with a simple interface.

Developed by Leonard Richardson, BeautifulSoup is commonly used via the bs4 package. The library is open-source and BSD-licensed. It supports multiple parsing backends, including Python's built-in html.parser, lxml, and html5lib. If a preferred parser isn't installed, it will fall back to the built-in parser.

Core features include a navigable parse tree, methods such as find, find_all, find_parent, and select for CSS-style queries, and straightforward traversal of parent, siblings, and children. The library is designed to handle imperfect markup and to produce reliable data structures that can be inspected and transformed.

Usage example: from bs4 import BeautifulSoup; soup = BeautifulSoup(html, 'html.parser'); for link in soup.find_all('a', href=True): print(link['href'])

BeautifulSoup emphasizes simplicity and readability. For very large HTML documents, choosing a faster parser such as lxml can improve performance, while the built-in parser offers broad compatibility. It is widely used for web scraping, data extraction, and quick prototyping of data pipelines.