Can Google API affect email deliverability?

[Eliel Junior]

Hello,

On our platform, we use the Google API to send emails on behalf of our users. Recently, we've been receiving reports from users that emails sent through our platform are being filtered into spam folders. At first glance, the primary factor affecting reputation in this process was the user's domain (since we are using the Google API), but by analysing the email headers, I found that Google adds metadata to identify the platform ID in its cloud.

In my research, I found a few unreliable sources claiming that Google can use that ID to limit email deliverability if it detects suspicious behavior. Another potential implication is using the same ID for all clients and, because of a "shared reputation", the platform be interpreted as a spammer.

Do you know if those topics are true? In addition to domain reputation, Google's servers can use the Platform ID to assess email risk. Is it true that using the same ID for multiple clients can diminish our deliverability?

Tks