Similarweb gets data from search engines, public databases, and third-party partners. It also tracks millions of activities on the internet for information.

In summary, SimilarWeb uses the following data sources:

1. Direct data from website owners.
2. Data from partners and internet providers with millions of users.
3. Public data sources: patented technologies and indexing mechanisms that are constantly scanning public data.
4. Anonymized panel data from browser extensions on visited websites.

Earlier, we mentioned that Similarweb uses several data sources, most notably a large panel of global Internet users.

That said, let’s dig a little deeper into these data sources.

1. Direct first-party data. This comes from people voluntarily sharing their Internet activity with SimilarWeb.
2. External Data Providers. SimilarWeb’s partners, draw data from companies with millions of users.
3. Contributed networks. Similarweb uses anonymous data collected from contributed networks. However, this data is anonymous because it is collected from the website level and not from individual devices. Therefore, it lacks personally identifiable information (PII).
4. Public data. Similarweb uses its own indexing engine to crawl a large cache of public online data.

Some surveys conducted on the Internet tell us that professionals believe that these four data sources (and other tests) indicate that Similarweb’s data is relatively accurate enough to estimate the size of a site’s traffic over time and to make decent site comparisons.

Similarweb has pro and free versions. The latter is quite limited, though. If you’re going to try it as an individual user, it might work for you. But it’s not the best option for companies.

Here`s a list of the best alternatives for SimilarWeb Pro:

• Google Analytics
• Semrush
• Ahrefs
• Data.ai
• Matomo
• Clicky
• Mixpanel
• Woopra