PSA: Starting this month, any apps that use the Gmail API must now undergo a security audit by a big name firm.
Google estimate that this will cost between $15k and $75k.
This is going to effectively cripple many small companies and indie developers who make improvement tools for Gmail.
More info here: https://cloud.google.com/blog/products/g-suite/elevating-user-trust-in-our-api-ecosystems