With Mailgun, you'll need to upgrade to a dedicated IP or "managed email service" and pay extra for "better deliverability." At Postmark, great deliverability isn't an up-charge. It's simply included, and we share live delivery data so you can judge for yourself.

Many mail systems allow recipients to report mail as spam or junk, and mail streams from senders whose mail is often reported as junk tend to have poor deliverability. Hence, the mailers want to make it as easy as possible for recipients to unsubscribe; if an unsubscription process is too difficult, the recipient's alternative is to report mail from the sender as junk until the mail no longer appears in the recipient's inbox.