Web crawling and web scraping are related concepts that both involve automatically traversing or extracting data from websites. However, there are some key differences:
What is Web Crawling?
Web crawlers, also known as spiders or bots, are programs that systematically browse the web in an automated fashion. Their main goal is to discover new web pages and content to be indexed by search engines.
Some examples of popular web crawlers are:
Key Functions of Web Crawlers
So in summary, web crawlers focus on the discovery and indexing of web pages rather than the extraction of specific data.
What is Web Scraping?
Web scraping refers to extracting data from websites through an automated process. Unlike web crawlers, web scraping focuses on gathering specific information from web pages rather than just discovering new URLs.
Key Functions of Web Scraping
So web scrapers are more specialized data extraction programs compared to standard web crawlers. Popular libraries used for web scraping include BeautifulSoup, Selenium, Scrapy and more.
Key Differences
| Web Crawling | Web Scraping |
| Discovers new web pages to index | Extracts specific data from web pages |
| Focuses on gathering URLs and links | Focuses on gathering textual data, images etc |
| Used by search engines for indexing | Used for scraping data for analysis |
| Broad coverage of the web | Narrow data extraction from specified sites |
FAQ
Is Google a web crawler or web scraper?
Google operates the Googlebot web crawler to discover new web pages for its search index. It is not a web scraper.
Is web scraping illegal?
Web scraping is generally legal unless explicitly forbidden by a site's terms of service. However, scraping at large scales can be considered data theft or denial of service attacks.
What are some alternatives to web scraping?
Some alternatives are using official APIs if available, data partnerships, manually copying data or using services like proxies or web data integration platforms.