# coss.com vs AgentMail (https://coss.com/compare/agentmail)

> AgentMail is a fuller email client for agents. coss.com Inboxes gives agents threads and replies on the platform that also sends your email and SMS.

Both give each AI agent its own address, keep mail as threads, extract the reply from the quoted conversation and send a webhook per message. AgentMail adds drafts, labels, WebSockets, IMAP and SMTP, and a calendar. coss.com Inboxes builds on its email product: the same domains, deliverability, suppressions, logs and API key as your transactional email.

Facts about AgentMail checked on 2026-10-30 against the sources listed below.

## At a glance

| | coss.com | AgentMail |
| --- | --- | --- |
| Free | 3 inboxes and 3,000 received emails a month | 3 inboxes, 3,000 emails a month (100 a day) |
| Paid | Per inbox: $0.99 per 30 inbox-days for the first 3,100; $0.24 per 30 inbox-days from 3,101 to 31,000; $0.045 per 30 inbox-days beyond 31,000 | Developer $20 a month (10 inboxes); Startup $200 a month (150 inboxes) |
| Most inboxes | 1,000 on Pro, 10,000 on Scale | 150 on Startup; up to unlimited on Enterprise |
| Addresses | At coss.com's inbound domain (no DNS setup; receive-only in live environments) or your own receiving domains | At AgentMail's domain, or custom domains on paid plans |
| Real-time events | Webhooks (inbox.message.received); coss listen while you develop | Webhooks and WebSockets |
| Threads and reply text | Threads, each message's extracted_text without the quoted conversation | Threads, reply extraction |
| Drafts and labels | — | Both |
| IMAP and SMTP | — | Both |
| Multi-tenancy | Projects and environments, sandbox and live | Pods |
| SSO | Scale and Enterprise | Social sign-in on every plan; OIDC and SAML on Enterprise |
| Same account | Transactional and marketing email, SMS, Verify, Risk | Calendar |

## When AgentMail is the better choice

- **Your agent needs a full mailbox.** Drafts for human review and scheduled sends, labels to track state, allow and block lists, and a calendar with invitations. coss.com Inboxes has none of these.
- **You connect over IMAP or WebSockets.** AgentMail speaks IMAP and SMTP for ordinary mail clients, and streams events over a WebSocket without a public URL.
- **Agents send from a shared domain on day one.** AgentMail's free inboxes send and receive at its domain. coss.com's live inboxes at its inbound domain only receive: sending needs one of your own domains.

## When coss.com is the better choice

- **Your email is already on coss.com.** Inboxes reply from the domains you send from, with the same deliverability, suppressions, delivery events and logs as your transactional email.
- **Agents that also text and verify.** The same API key sends SMS, one-time codes and Risk assessments, so an agent's tools come from one SDK.
- **Priced per inbox, by the day.** An inbox costs only the days it exists, so short-lived agent inboxes don't pay for a month.
- **Sandbox environments.** Sandbox inboxes send and receive without touching production mail or your bill.

## Moving from AgentMail

1. **Set up receiving.** Start at the environment's inbound domain with no DNS, or add your own receiving domain for addresses you already use. (/docs/email/receiving)
2. **Create the inboxes.** AgentMail's inboxes become coss.inboxes.create({ username, client_id }); client_id makes a repeat create return the same inbox. (/docs/inboxes)
3. **Move the event handler.** Subscribe a webhook endpoint to inbox.message.received, read the thread with coss.inboxes.threads.get() and reply with coss.inboxes.messages.reply(). (/docs/inboxes/threads)

## Frequently asked questions

### Can a coss.com inbox send email?

Yes, from one of your own domains, and every inbox can send in sandbox environments. Live inboxes at coss.com's shared inbound domain only receive.

### Does coss.com support IMAP for agent inboxes?

No. coss.com inboxes are read through the API, the SDK, the CLI and the MCP server, with a webhook for each message. AgentMail offers IMAP and SMTP.

### How are coss.com inboxes priced?

Every plan includes a few inboxes; beyond them an inbox is billed for each day it exists, and received mail by the thousand. The current rates are on coss.com/pricing.

### Does coss.com strip quoted replies?

Yes. Each message in a thread has extracted_text, its own words without the quoted conversation or the signature, which is what an agent should read.

## Sources

- [AgentMail pricing](https://www.agentmail.to/pricing)
- [AgentMail docs index](https://docs.agentmail.to/llms.txt)
- [AgentMail: drafts](https://docs.agentmail.to/drafts)
- [AgentMail: IMAP and SMTP](https://docs.agentmail.to/imap-smtp)
- [AgentMail: WebSockets](https://docs.agentmail.to/websockets)
- [AgentMail: pods](https://docs.agentmail.to/documentation/core-concepts/pods)