The short answer
Mektup lets a person read and answer the same mailbox as the agent, gives you as many inboxes as you need without paying per inbox, and uses the same addresses to send your app's mail and catch your website forms.
What AgentMail has that Mektup does not: a free plan, and enterprise options (SOC 2 report, EU or your own cloud, SSO, dedicated IPs).
Features
| Mektup | AgentMail | |
|---|---|---|
| Send and receive through an API | Yes, REST API and CLI | Yes |
| MCP server | Remote with OAuth, or local with npx | Yes |
| Webhook on new mail | Yes, HMAC-signed | Yes |
| IMAP for mail apps | Every folder, mailbox password | Inbox folder only, API key as password |
| SMTP | 465 and 587 | 465 |
| Webmail for people | Yes | No, a developer console |
| Website forms into a mailbox | Built in | No |
| Mailboxes | Unlimited on Starter | 3, 10 or 150 by plan |
| Custom domains | 25 on Starter | None on Free, 10 on Developer, 150 on Startup |
| Free plan | No | Yes |
AgentMail pricing compared
| You need | Mektup | AgentMail |
|---|---|---|
| A few inboxes to try things | $20 (Starter) | Free: 3 inboxes, 3,000 emails, AgentMail's domain |
| 10 inboxes on your domain | $20 | $20 (Developer: 10,000 emails a month, 2 seats) |
| 50 inboxes | $20 | $200 (Startup) |
| 150 inboxes | $20 | $200 (Startup) |
Per month, from each company's pricing page on 23 October 2026. Mektup's Starter covers 50,000 sent emails a month (2,000 a day, 300 an hour), counted per recipient; received mail is free. Above that, Enterprise is quoted per account.
Where the difference shows
A person in the same inbox
Agents get things wrong, customers ask for a human, and someone has to check what was sent. In Mektup the agent works through the API or MCP while your team opens the same mailbox in webmail, Apple Mail or Outlook, with every folder and the agent's replies in Sent. With AgentMail a person can read the inbox folder over IMAP, but there is no webmail for a team, and the other folders live behind the API.
Inboxes as a cost
A fleet of agents, an inbox per customer or an inbox per workflow adds up when every inbox is billed. On Mektup's Starter the number of mailboxes is unlimited; you pay for domains, storage and the mail you send.
One address for everything
The mailbox an agent answers from can also send your sign-up codes and receipts through the same API, and receive your website's contact form, instead of an agent inbox next to a sending API next to a form service.
Moving from AgentMail
- Add your domain in Mektup (dashboard, API or
create_domain) and add the MX, SPF, DKIM and DMARC records it returns. - Create a mailbox per agent with
create_mailboxorPOST /v1/domains/:domain/mailboxes. - Set each mailbox's webhook to your agent with
set_mailbox_webhookand verify theX-Mektup-Signatureheader. - Change the send call to
POST https://api.usemektup.com/v1/emailsor thesend_emailtool. - Give your team the mailbox login so they can open the same mailbox.
Other AgentMail alternatives
- Hostinger Agentic Mail: API, webhooks and MCP on Hostinger business mailboxes, with Hostinger webmail. A fit if your mail is already at Hostinger.
- Nylas Agent Accounts: a Nylas-hosted mailbox and calendar for an agent, inside the Nylas API, with IMAP/SMTP through an app password.
- Resend: a sending API with inbound webhooks and an Inboxes product in private beta. Mektup vs Resend.
- Gmail with the Gmail API: real mailboxes, billed per user through Google Workspace. Mektup vs Google Workspace.