What is Google Sandbox?
Google Sandbox is the term SEOs use to describe an unconfirmed filter that supposedly prevents new sites from appearing in Google search results.
SEOs who believe in the existence of this filter say sandboxed sites will not appear in Google search results, no matter how good their SEO is. However, the site will appear when you search site:yourdomain.com on Google.
Google has confirmed that it doesn’t have a sandbox but does have some algorithms that may behave like one. These algorithms try to understand how the new site compares with those already ranking for the same keyword.