Postmark vs Mails.ai
Both sit in email marketing. Here is how they differ on the things you can actually check.
On price: Postmark starts $5 a month cheaper than Mails.ai ($15 against $20, 25% less) on its Basic tier. Both figures were read from the vendors' own pricing pages on the dates shown below.
Postmark
postmarkapp.com
Focused purely on transactional sending — receipts, password resets, notifications — with a reputation for fast delivery and detailed per-message logs. Part of ActiveCampaign.
Mails.ai
mails.ai
Gives an AI agent a real mailbox: inbound arrives as structured reply events carrying a prompt-injection score and sender reputation, with a six-category injection scanner on every message, dedicated IPs and an MCP server. Cold email is refused at the API rather than in the fine print.
| Postmark | Mails.ai | |
|---|---|---|
| Entry price | $15/mo | $20/mo |
| Entry plan | Basic | Pro |
| Paid annually | — | — |
| Price checked | 21 Sept 2026 | 21 Sept 2026 |
| Pricing model | Free trial | Free plan |
| Free plan | No | Yes |
| Category | Email Marketing | Email Marketing |
| Around since | 2010 | 2025 |
Every price here was read from the vendor's own pricing page, most recently on 21 Sept 2026. Entry tier only — vendors change pricing without notice.
Postmark vs Mails.ai, answered
- Is Postmark cheaper than Mails.ai?
- Yes. Postmark starts at $15 a month against Mails.ai's $20, 25% less.
- Do Postmark or Mails.ai have a free plan?
- Mails.ai publishes an ongoing free plan; Postmark does not.
- What is the difference between Postmark and Mails.ai?
- Postmark: Focused purely on transactional sending — receipts, password resets, notifications — with a reputation for fast delivery and detailed per-message logs. Part of ActiveCampaign. Mails.ai: Gives an AI agent a real mailbox: inbound arrives as structured reply events carrying a prompt-injection score and sender reputation, with a six-category injection scanner on every message, dedicated IPs and an MCP server. Cold email is refused at the API rather than in the fine print.
