Email deliverability for SaaS companies
Where the addresses come from
- Product signups, where the address is the account identifier and a typo blocks the person from ever confirming it.
- Free trial sign-ups, which attract throwaway addresses from people testing without committing.
- In-app invitations, where an existing user types a colleague's address from memory.
- Webinar and content downloads, the highest-bounce source in a typical SaaS funnel.
Transactional mail is not optional
A marketing campaign landing in junk costs you a conversion. A password reset landing in junk generates a support ticket and a churn risk, and the two often share a sending domain and an IP reputation.
Amazon SES makes this explicit: a bounce rate of 5% puts the account under review and 10% can pause sending entirely, which stops password resets along with the newsletter. Teams discover this when a marketing import takes their login emails offline.
The separation is straightforward and rarely done. Different subdomains, different IP pools or different providers for product mail and marketing mail, decided before the first large campaign rather than after the first incident.
What the results tend to look like
SaaS lists skew toward business domains, which means a high catch-all share, and toward free trial signups, which means more disposable and role addresses than a purely consumer list would carry. Expect a meaningful slice that no checker can resolve.
What to do about it
Split product mail from marketing mail
Separate subdomains at minimum, separate sending systems where the stakes justify it. A marketing list problem should not be able to stop a password reset.
Check at signup rather than in batches
The address is the account key, so catching a typo while the person is still on the form is worth more than any later cleaning pass. Use a short timeout and never block a sign-up on a non-answer.
Watch activation drop-off against your bounce log
A cohort that never activated and never received the confirmation email is a delivery problem wearing a product metric.
Treat trial signups as a separate segment
They bounce and complain at higher rates than customers, and mixing them into one list means the trial traffic sets your reputation for everyone.
Questions people ask
Should transactional and marketing email share a domain?
Not if you can avoid it. A shared reputation means a marketing list problem can delay or filter your password resets, which is a support and churn problem rather than a marketing one.
Why do free trial signups bounce so much?
Because testing a product is low commitment. People use throwaway addresses, role addresses and occasionally invented ones, and a trial that requires no payment details invites all three.
Does checking help activation rates?
Where activation depends on a confirmation email, yes. A typo caught at the form is a user who activates, and one caught in a later cleaning pass is a user who already left.
Related sectors
See the breakdown on your own list
100 free checks a month, no card. Addresses we could not get an answer on come back labeled rather than guessed at, and we do not bill them.