Disclosure: I have no affiliation with any of the seven companies below. Nobody paid for this post. I've used all seven myself at one point or another, and they all genuinely work well, this ranking is personal preference, not a verdict.
Source: [Dev.to](https://dev.to/alexgeorgiev17/7-smtp-apis-worth-knowing-in-2026-and-where-id-start-34g4)