It depends on the tool, google has its official Indexing API, which doesn't violate policies, but it's only allowed for job postings and live video events, if you use it for regular blog pages, you're violating the rules and your access could be revoked, third party indexing tools are a gray area, some claim to use different methods, but if they promise to quickly index content that isn't related to jobs or events, google will eventually detect them as abuse, several users have already reported that their accounts were affected by using these services.
My advice is to stay away from these tools for regular content, what works safely is using updated sitemaps, good internal links, and sharing your content on social media. It's slower, but you don't put your account or your site at risk.