Customer.io vs Mails.ai
Both sit in email marketing. Here is how they differ on the things you can actually check.
On price: Mails.ai starts $80 a month cheaper than Customer.io ($20 against $100, 80% less) on its Pro tier. Both figures were read from the vendors' own pricing pages on the dates shown below.
Customer.io
customer.io
Triggers messages from product events rather than lists — email, push, in-app and SMS driven by what a user actually did. Data-warehouse-friendly.
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.
| Customer.io | Mails.ai | |
|---|---|---|
| Entry price | $100/mo | $20/mo |
| Entry plan | Essentials | 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 | 2012 | 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.
Customer.io vs Mails.ai, answered
- Is Customer.io cheaper than Mails.ai?
- No — Mails.ai is the cheaper entry point, at $20 a month against Customer.io's $100, 80% less.
- Do Customer.io or Mails.ai have a free plan?
- Mails.ai publishes an ongoing free plan; Customer.io does not.
- What is the difference between Customer.io and Mails.ai?
- Customer.io: Triggers messages from product events rather than lists — email, push, in-app and SMS driven by what a user actually did. Data-warehouse-friendly. 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.
