Postmark
Postmark is a transactional email API/SMTP relay owned by ActiveCampaign, which acquired it (and DMARC Digests) from Wildbit in May 2022. Proprietary SaaS with no self-host option; free trial caps at 100 emails/month. Paid plans start at $15/mo (Basic), $16.50/mo (Pro), or $18/mo (Platform), all covering 10,000 emails/month but with different overage rates ($1.80, $1.30, $1.20 per additional 1,000 respectively) — at 500,000 emails/month effective cost ranges roughly $606-$897/mo depending on tier. Technical differentiator: "Message Streams" isolate transactional from broadcast traffic so bulk sends don't damage transactional sender reputation. Independent 2026 inbox-placement testing (EmailToolTester) measured a 93.8% average across four test rounds — three rounds landed 95-97%, one dropped to 87% during an apparent Microsoft-specific dip — solid but not a clean win over rivals; a widely-repeated "98.7%, ahead of SendGrid's 95.3%" figure traces to unverifiable SEO content and could not be confirmed against the primary test data. Named customers: 1Password, Paddle, Webflow, Asana. Current version/status: SaaS, current July 2026 (owned by ActiveCampaign since May 2022). License: proprietary SaaS. Pricing: Free trial 100 emails/mo; paid tiers start at $15/mo (Basic), $16.50/mo (Pro), or $18/mo (Platform) for 10,000 emails, with overage of $1.80/$1.30/$1.20 per additional 1,000 res
Pick Postmark when password resets and receipts absolutely cannot land in spam and you'll pay a premium for that guarantee — Message Streams plus a deliverability-only focus (no bulk marketing mixed into the same reputation pool) is the actual product. Skip it for cost-sensitive high volume: at 500K emails/month Postmark's cheapest tier runs ~$606/mo versus Mailgun Scale (~$530), Resend Scale ($350/mo flat), or raw AWS SES ($50/mo) — use SES if you'll build your own bounce/complaint handling, Resend if you want the cheapest developer-first option. Postmark's own docs admit the gap themselves: there's no tier between the 100-email free trial and the 10,000-email paid floor, so tiny hobby projects get pushed straight to full price. Known weakness: No pricing tier exists between the 100-email/month free trial and the 10,000-email paid floor, so very low-volume hobby projects pay full price immediately — and per-email cost stays well above Resend, Mailgun, or AWS SES at high volume.
See how it ranks →