Quick answer
MailChannels - MailChannels wins for most builders who want a free email API with simpler scale-up economics, while AgentMail is better only if you specifically need inbox management features for AI agents.
How the free tiers compare
These two free tiers are both usable, but they optimize for different jobs. AgentMail is built around programmatic inboxes for agents: creating inboxes, managing threads and replies, handling attachments, and working with webhooks and MCP. Its free tier is narrow but feature-shaped, with only 3 inboxes and 3,000 emails per month, so it is best when the product itself depends on mailbox lifecycle control rather than bulk sending. MailChannels is closer to general email infrastructure. Its free tier also includes 3,000 emails per month, but it gives you REST API and SMTP integrations, 30-day logs, deliverability features, and up to 3 domains. The paid step is also gentler: MailChannels starts at $10/month for 10,000 emails, while AgentMail starts at $20/month for 10 inboxes and 10,000 emails. If you are choosing a free tier to grow out of, MailChannels is the more flexible default.
AgentMail vs MailChannels free tier, side by side
| AgentMailFTV 47 | MailChannelsFTV 42 | |
|---|---|---|
| Free emails per monthMailChannels also caps free sending at 100 emails per day and says no overages. | 3,000 | 3,000 |
| Free inboxes / domainsThese are not the same unit, so the comparison is about shape, not direct equivalence. | 3 inboxes | Up to 3 domains |
| Free storage / logsAgentMail includes storage quotas; MailChannels emphasizes log retention instead. | 3 GB storage | 30-day transaction log retention |
| Free integrationsAgentMail is more inbox-workflow oriented; MailChannels is more standard email infrastructure. | REST APIs, SDKs, webhooks, MCP support | REST API and SMTP integrations |
| Free team accessOnly include what is explicitly listed. | 2 team members | Not specified |
After you outgrow the free tier
AgentMail uses flat monthly pricing on its first two paid tiers, then switches to custom contact-sales enterprise pricing with usage-based elements. MailChannels starts with a usage-based plan from $10/month across 10K to 1.5M emails, then moves to custom pricing above 1,500,001 emails. For small-team usage, MailChannels is cheaper at the first paid step and scales more gradually with volume. AgentMail costs more at entry, but you are paying for inbox count and agent-oriented mailbox features rather than just message throughput.
Cost at real usage
| Usage | AgentMail | MailChannels |
|---|---|---|
| 10,000 emails/moAgentMail Developer includes 10,000 emails/month and 10 inboxes. MailChannels starts at 10,000 emails/month from $10/mo. | $20/mo | $10/mo |
| 150,000 emails/moMailChannels lists volume tiers through 1.5M emails but does not provide the exact price ladder here. | $200/mo | varies by usage / contact sales |
| 300,000 emails/moAgentMail’s Enterprise and MailChannels custom plans both require sales contact in the provided data. | contact sales / custom | varies by usage / contact sales |
Estimates, not quotes. Usage-based rates change - verify with the vendor's pricing page before committing.
When to pick each one
Pick AgentMail when…
- You are building an AI agent that needs its own inboxes, threads, replies, and attachment handling.
- You want webhooks and MCP support tied to inbox workflows.
- You only need a small number of inboxes, but need programmatic control over each one.
- You expect to outgrow the free tier by inbox count, not just by email volume.
Pick MailChannels when…
- You are sending transactional email from an app and want SMTP plus REST API support.
- You need basic deliverability and log retention out of the box.
- You want to keep costs lower when moving beyond the free tier.
- You need up to 3 domains on the free plan and may later scale volume without buying inbox slots.
Bottom line
For the most common builder use case, MailChannels is the better pick because it gives you a usable free tier, standard email integrations, and a cheaper first paid step once you grow. AgentMail only pulls ahead if your product really needs inbox-as-a-resource behavior for AI agents, such as creating and managing many isolated inboxes, threads, and replies. If you are building transactional email or platform email plumbing, MailChannels is the safer default. If you are building agent workflows around email accounts, choose AgentMail.
Read the full listings: AgentMail and MailChannels. Scores use the FTV methodology at /ftv. Browse more head-to-heads on /compare, or see the top-ranked free tiers on /top.