Technical Requirements for SEO
For a website to be found and indexed by Google, essential technical requirements need to be met. The first and most fundamental is ensuring that Googlebot is not blocked. Google indexes web pages that are publicly accessible and do not block its crawler. If a website blocks Googlebot through robots.txt or other methods, it may not be included in search results.
The page also needs to work correctly, which generally means Google should receive an HTTP 200 success status when accessing it. Pages that return errors, such as 404 Not Found, are not indexed as valid pages. Another fundamental requirement is indexable content — text that Google can read and understand. Pages containing only images, videos or other non-text elements without adequate descriptions may be harder to index correctly.
Googlebot access
When Google crawls a page, ideally it should perceive the content in much the same way as an ordinary user. Google therefore needs access to the same resources as the user's browser. If a website hides important components such as CSS or JavaScript from Google, the search engine may not understand the pages properly, which can affect their appearance and performance in search results.
Google discovers pages mainly through links from pages it has already crawled. In many cases those are links from other websites, which tend to emerge naturally over time. Website promotion can also help people discover content. A sitemap can make crawling easier by listing the site's important URLs, and some content management systems can generate and submit sitemaps automatically.
Site organization and URLs
When building or redesigning a website, organizing information logically helps both search engines and users understand how pages relate to the rest of the site. Descriptive URLs are recommended because parts of a URL may appear in search results as breadcrumb-like navigation, helping users judge whether a result is useful. Google can infer this structure from URL words and may also be guided by appropriate structured data.
If a site contains more than a few thousand URLs, content organization can affect how Google crawls and indexes it. Using directories to group similar topics can help Google infer how often URLs in individual areas tend to change. A policy directory, for example, may change rarely, while a promotions directory may change frequently.
Checking visibility for Google
To verify that Google can see a page in a way comparable to a user, make sure it can access the same resources as the user's browser. Blocking important CSS or JavaScript resources can make it harder for Google to understand the page correctly.
If pages show different information depending on a user's physical location, verify what Google sees from the crawler's location, which is often in the United States. The URL Inspection tool in Search Console can help show how Google sees and interprets a specific page.
Controlling crawling and indexing
Sometimes an entire website or particular sections should not appear in search results. Google supports several ways to control crawling and indexing. Depending on the objective, files, directories or pages can be restricted using methods such as noindex directives, robots.txt rules or password protection.
There is no financial cost to have an eligible page appear in Google Search. If a page meets the minimum technical requirements, it can qualify for indexing. Even then, Google does not guarantee that every eligible page will be indexed.