Email API focused on developer flexibility, Sinch-owned, strong free tier
Mailgun (acquired by Sinch in 2021) sits in the middle of the email API category — broader feature set than Postmark, smaller scale than SendGrid, often the cost-effective choice for mid-market volume. The developer experience emphasizes flexibility: SMTP and HTTP API both first-class, inbound parsing, deliverability tools, and a generous free tier. The Sinch acquisition has been mostly positive for product development but the company occasionally feels less focused than its smaller, founder-led competitors. Best fit: teams that want one provider for transactional + marketing email without paying SendGrid prices.
Inbound parsing solved a problem nobody else solves cleanly.
We have a use case where users reply to our emails and we treat the reply as an action. Mailgun inbound parsing handles MIME, attachments, threading metadata. The only competitor that ships this clean is AWS SES, which has its own pain.
Cheapest at 100-500K/mo for our use case.
500K emails/mo at Mailgun is ~$90. SendGrid for the same is ~$300+. Postmark $625. Mailgun wins on price at our volume.
Moved to Postmark for deliverability. Mailgun was fine but Postmark is better.
After a sender-reputation incident with Mailgun took a week to resolve, we tried Postmark. Open rates jumped 8 points. Migration was worth it.
Methodology
Every review on this page is verified through GitHub OAuth and weighted by reviewer credibility, use-case match, and conflict-of-interest disclosure. Aggregate scores combine with recency decay so rankings reflect current reality. Read full methodology →
