SESS is tightly wired to use SES (AWS). We do a bunch of algorithmic checks to validate email/domain validity plus assessing the risk-factor of uploaded email l

SESS is tightly wired to use SES (AWS). We do a bunch of algorithmic checks to validate email/domain validity plus assessing the risk-factor of uploaded email list. If you have a clean list deliverability is closer to 100%. Edit: Thanks for the note. I will make a mention of the deliverability on the site.