What is a Crawler?
A web crawler is a computer program that visits websites automatically. It works a bit like a librarian who goes through every book in a library, page by page. This post will help you understand how it works and how it is beneficial to your website.
Web crawler visualized as a spider robot
How Does a Crawler Work?
The crawler starts at one webpage and reads all the content on that page. Then it follows the links on that page to find new pages. This is similar to how you might start reading a book, then check out other books mentioned in the footnotes.
The crawler keeps doing this over and over:
- Visit a page
- Read the content
- Find links to other pages
- Add those pages to its list
- Move on to the next page
Why Are Crawlers Important for Search?
For a website to have good search, the search tool needs to know what's on each page. This is where crawlers help.
When you add search to your website, the crawler first needs to visit all your pages. It collects information about what words appear on each page. Later, when someone searches for a word, the search tool can quickly tell them which pages have that word (more on that in our post on how indexing works).
Crawlers and SEO
Search engines like Google use crawlers too. Their crawlers visit billions of websites to build their search index. If Google's crawler can't access your site, your pages won't show up in search results.
Common Crawler Questions
Are crawlers bad for my website?
No! Crawlers are necessary for search to work. They do use some of your website's resources, but good crawlers are designed to be polite and not overload your site.
How often do crawlers visit?
This depends on the search tool. Some visit daily, others weekly. The best search tools let you control how often crawling happens.
Can I control what gets crawled?
Yes. Most websites use a file called "robots.txt" to tell crawlers which pages they should or shouldn't visit.
Adding Search to Your Website
Adding search to your website doesn't have to be hard. With the right tools, you can have a crawler index your site and provide great search results to your visitors without any coding.
A good search tool, such us our no-code search widget, will handle the crawling for you, making sure your visitors can always find what they're looking for.