we are trying to automate outgoing emails for our SaaS product. Currently, each customer is required to configure their own smtp server which are used to send emails from their account (and from their domain), but we are looking at automating this in our product platform.
- Each customer should be able to send emails "from" their own domain. The from address should be a domain address of the user.
- We can get an account created with a transactional email provider like mailgun or sendgrid, and use that account to send email for all of our customers. However, we need to sign all emails with our domain. Due to DMARC, this can pose deliverability issues. Moreover, even if one customer mis-ueses, reputability of the sending domain (our own domain) is lost --which might affect all our customers.
It is not practical to ask each customer to verify their own domain using DNS verification.
What are the best practices while sending domains in a SaaS set up where the email should be sent from the customer's domain?