Effective January 2019, new Gmail API policies significantly limited permitted Application Types which are allowed access to Gmail. Google’s primary concern is how private user data is used and handled by 3rd-party apps and how it must be secured. Per Google:
💡 How Data May Not Be Used: 3rd-party apps accessing these APIs must use the data to provide user-facing features and may not transfer or sell the data for other purposes such as targeting ads, market research, email campaign tracking, and other unrelated purposes. (Note: Gmail users' email content is not used for ads personalization.)
💡 Attention: We have also clarified that human review of email data must be strictly limited.
💡 How Data Must Be Secured: It is critical that 3rd-party apps handling Gmail data meet minimum security standards to minimize the risk of data breach. Apps will be asked to demonstrate secure data handling with assessments that include: application penetration testing, external network penetration testing, account deletion verification, reviews of incident response plans, vulnerability disclosure programs, and information security policies.
Prior to this change it was very common for email cleaning applications to provide their services for free by monetizing data from emails.
Here at Clean Email, we are committed to your security and privacy. We don't keep, sell, or analyze your data for the purposes beyond our public features. Instead of relying on data from emails to sustain our business we’ve chosen to charge a reasonable fee in exchange for our services.