Is there a way how to get related:{website_name} from google programmatically - not using web-scraping?

I know that you can search google for related sites like this, but how can I get those results from code? I'm currently using bots that are web-scraping it, but there are captchas, etc. and it takes so long (approximately 70 seconds for 3-10 websites) to get a proper result.

Are there more ways to achieve it quicker? I know that there are sites like sitelike.org and similiar, but these have no API. Or atleast I don't know about it. Also scraping those sites is not an option I think.

I need this because on the site we are creating we have to show 'competitors' - which usually are the sites which are related.