> For the complete documentation index, see [llms.txt](https://doc.thordata.com/doc/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.thordata.com/doc/faq/product-problem/serp-api/how-is-serp-api-billed.md).

# How is SERP API billed?

The docs state that billing applies only when a request returns a **200 status code**. Status codes such as 300, 400, 401, 403, 404, 429, 500, and 504 are not billed. Billing is based on successful responses, not on the number of results returned.