HTML version: https://cooperemail.com/compare/agentmail

- [Home](/)
- › [Compare](/compare)
- › AgentMail

Cooper Email is an email API that gives each AI agent its own inbox. [Free is $0 and includes 5 inboxes and 5,000 emails a month](/pricing).

Retrieved 2026-11-05 · Updated 2026-10-11

# Cooper Email vs AgentMail (2026)

On the lists re-read 2026-11-05, Cooper’s free tier is larger and its entry plan costs less. AgentMail is ahead where you need a SOC 2 report, WebSockets, or SMTP. Both let an agent sign itself up.

Sources: [AgentMail pricing](https://www.agentmail.to/pricing) · [AgentMail pay as you go](https://www.agentmail.to/blog/pay-as-you-go) · [AgentMail rate limits](https://www.agentmail.to/docs/knowledge-base/rate-limits) · [AgentMail llms.txt (agent sign-up)](https://www.agentmail.to/llms.txt) · [Cooper pricing](https://cooperemail.com/pricing)

|  | [AgentMail](https://www.agentmail.to/pricing) | [Cooper Email](/pricing) |
| --- | --- | --- |
| Free | [$0 · 3 inboxes · 3,000 emails/month · 100/day · 3 GB · 1 custom domain · “Sent via AgentMail” footer](https://www.agentmail.to/pricing) | [$0 · 5 inboxes · 5,000 emails/month · 1 custom domain · 5 GB · no separate daily cap · no footer](/pricing) |
| Entry paid | [Developer $20/month · 10 inboxes · 10,000 emails/month · 1,000/day · 10 domains · 10 GB](https://www.agentmail.to/pricing) | [Starter $12/month · 25 inboxes · 25,000 emails/month · 15 custom domains · 25 GB](/pricing) |
| Team paid | [Startup $200/month · 150 inboxes · 15,000/day (the pricing page monthly cell is “—”; 150,000/month per their pay-as-you-go post and rate-limits doc) · 150 domains · SOC 2 report](https://www.agentmail.to/pricing) | [Pro $99/month · 300 inboxes · 250,000 emails/month · 200 custom domains · 100 GB · no SOC 2 report](/pricing) |
| Overage | [$2 / extra inbox, domain, or 1,000 sends, on Developer or Startup](https://www.agentmail.to/pricing) | [$1 / extra inbox or domain, $1 / 1,000 emails. Starter and Pro set the quantity with POST /api/v1/billing/addons. The cap rises only after Stripe confirms payment. Free cannot buy these. Included caps return HTTP 402 until then.](/pricing) |
| Agent self sign-up | [POST /v0/agent/sign-up with a human_email and username returns an API key; the human then gets an OTP to verify](https://www.agentmail.to/pricing) | [POST /api/v1/onboard (or the cooper_onboard MCP tool) with a username returns an API key and inbox; owner_email is optional](/pricing) |
| Hosted MCP | [Yes (listed on every plan)](https://www.agentmail.to/pricing) | [Yes, https://cooperemail.com/mcp (Streamable HTTP, OAuth or API key)](/pricing) |
| Real-time inbound | [Webhooks and WebSockets](https://www.agentmail.to/pricing) | [Signed webhooks, a 55-second long-poll wait, and Server-Sent Events. No WebSocket endpoint](/pricing) |
| SMTP | [SMTP relay listed on every plan](https://www.agentmail.to/pricing) | [No SMTP or IMAP. HTTP API and MCP only](/pricing) |
| Drafts and approval | [Drafts and scheduled send listed on every plan](https://www.agentmail.to/pricing) | [Drafts and scheduled send. An inbox in approval mode sends only after a verified human owner approves the exact draft](/pricing) |
| Search | [Threads, labels, and message APIs](https://www.agentmail.to/pricing) | [Account-wide full-text search plus per-inbox search with highlights](/pricing) |
| Compliance | [SOC 2 report on Startup and Enterprise](https://www.agentmail.to/pricing) | [No SOC 2 report](/pricing) |
| SMS | [Not listed](https://www.agentmail.to/pricing) | [Receive-only numbers on Starter and Pro. POST /api/v1/inboxes/{id}/sms returns HTTP 409 outbound_not_registered](/pricing) |
| EU region | [Listed on Enterprise](https://www.agentmail.to/pricing) | [Not offered](/pricing) |

## Which should I choose by use case?

[Free](/use-cases#free) is for a builder testing a few agents. [Starter](/use-cases#starter) is for one production agent on your domain. [Pro](/use-cases#pro) is for an inbox per customer or an agent fleet. [AgentMail alternative](/agentmail-alternative) is the short answer with a copy-paste install.

## Is Cooper Email cheaper than AgentMail?

On the lists re-read 2026-11-05, Starter is $12/month and AgentMail Developer is $20/month. Pro is $99/month and Startup is $200/month. Extra inboxes, domains, or 1,000 sends are $1 on Cooper and $2 on AgentMail. Enterprise on both sides is custom and is not quoted here.

## Which has the bigger free tier?

Cooper Free is 5 inboxes, 5,000 emails/month, and 1 custom domain, with no separate daily cap and no product footer. AgentMail Free is 3 inboxes, 3,000 emails/month, 100/day, 3 GB, 1 custom domain, and a “Sent via AgentMail” footer. AgentMail's pricing page lists 1 custom domain on Free; the rate-limits doc still says Free domains None, and this number matches the pricing page.

## Where does Cooper fall short?

Cooper has no SOC 2 report (see https://cooperemail.com/security), no WebSocket endpoint, and no SMTP or IMAP. AgentMail’s Startup plan includes a SOC 2 report, and its pricing page lists WebSockets and an SMTP relay. Enterprise there offers EU region, BYO cloud, and dedicated IPs. AgentMail also has a larger ecosystem and more SDK installs.

## Can an agent sign itself up on both?

Yes. AgentMail’s sign-up is POST /v0/agent/sign-up with a human_email and username, then the human verifies an OTP. Cooper’s is POST /api/v1/onboard, or the cooper_onboard MCP tool, with a username. owner_email is optional. Both have a hosted MCP server. Cooper’s is https://cooperemail.com/mcp.

## Which should I choose?

Choose AgentMail if you need a SOC 2 report, WebSockets, SMTP, or the larger ecosystem. Choose Cooper if you want the larger published free tier, the lower entry price, no footer on free mail, or drafts that wait for a verified human owner. The table is the list of figures. If a number here disagrees with the vendor page, use the vendor page.

- AgentMail's pricing page lists 1 custom domain on Free; the rate-limits doc still says Free domains None, and this number matches the pricing page.
- Enterprise on both sides is custom. This page does not quote an Enterprise price.
- Feature rows reflect what each pricing page or doc lists. A row saying a product lacks something means it was not listed or documented on the date above.
- Something out of date? Email ops@avatar33.com and we will correct it.

Agents ask

## Comparison FAQ

Same answers as the FAQ page.

### Is there a cheaper AgentMail alternative?

On the lists re-read 2026-11-05, Cooper Free is 5 inboxes and 5,000 emails/month with no daily cap. AgentMail Free is 3 inboxes, 3,000 emails/month, and 100/day. Starter is $12/month and AgentMail Developer is $20/month. Pro is $99/month and AgentMail Startup is $200/month. Extra inboxes, domains, or 1,000 sends are $1 on Cooper and $2 on AgentMail. AgentMail Startup includes a SOC 2 report. Cooper does not.

### Which has the bigger free tier, Cooper Email or AgentMail?

Cooper Free is 5 inboxes, 5,000 emails/month, and 1 custom domain, with no separate daily cap and no product footer. AgentMail Free, retrieved 2026-11-05, is 3 inboxes, 3,000 emails/month, 100/day, 1 custom domain, and a “Sent via AgentMail” footer. AgentMail's pricing page lists 1 custom domain on Free; the rate-limits doc still says Free domains None, and this number matches the pricing page.

### When should you stay on AgentMail?

Stay when you need a SOC 2 report (AgentMail lists one on Startup and Enterprise; Cooper has none), WebSockets, or an SMTP relay. AgentMail Enterprise also lists EU region, BYO cloud, and dedicated IPs. AgentMail has a larger ecosystem and more SDK installs. Those points are from their public pages retrieved 2026-11-05. Compare: [https://cooperemail.com/compare/agentmail.](https://cooperemail.com/compare/agentmail.)

### How do I migrate from AgentMail to Cooper?

Create a Cooper inbox with POST /api/v1/onboard, save the API key, and point the agent’s MCP config or HTTP client at [https://cooperemail.com.](https://cooperemail.com.) There is no mailbox import. Historical mail stays where it is. A custom domain moves by publishing the DNS records from POST /api/v1/domains, which starts on Starter. Compare the published limits at [https://cooperemail.com/compare/agentmail](https://cooperemail.com/compare/agentmail) before you switch.

### What is Cooper Email versus AgentMail, Resend, or the Gmail API?

Cooper is HTTP email for autonomous agents: one POST /api/v1/onboard returns a Bearer key and username@cooperemail.com, inbound arrives as a signed webhook, and every message on the account is full-text searchable. AgentMail is a mature agent-mail API with inboxes and threads; its published Free tier is 3,000 emails/month, 100/day, 3 inboxes, and 1 custom domain (agentmail.to/pricing, 2026-11-05). AgentMail's pricing page lists 1 custom domain on Free; the rate-limits doc still says Free domains None, and this number matches the pricing page. Resend is an excellent transactional sender — inbound is webhook-only, with no persistent searchable inbox. The Gmail API cannot create inboxes programmatically and typically OAuths a human mailbox, which is the wrong isolation model for agents. Cooper’s bet is one-request onboard, account-wide FTS, 1 custom domain on Free, and OpenAPI + MCP + webhooks in one surface.

[More answers on the FAQ](/faq)

[All comparisons](/compare) · [Pricing](/pricing) · [AgentMail alternatives](/alternatives/agentmail) · [FAQ](/faq)