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Mailbay vs AgentMail

Both give agents their own inboxes over an API and MCP. AgentMail is further along; Mailbay adds sending for apps, a support inbox and custom domains on the free plan.

Updated 4 min read

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In short

AgentMail is the product that made “inboxes for agents” a category. It is a good product: an API, Python and Node SDKs, MCP, IMAP and SMTP, webhooks and websockets, pods for multi tenant apps. Mailbay covers the same ground for agents and goes wider: custom domains on the free plan, sending for apps from any verified address, and a shared support inbox for people.

Pick AgentMail if

  • You want official Python or Node SDKs today.
  • You need a SOC 2 report, an EU region or white labelling (Startup and Enterprise plans).
  • You want features Mailbay does not have yet, such as drafts or a calendar per inbox.

Pick Mailbay if

  • You want your own domain on the free plan.
  • Your agent should wait for a code in one call, with codes and links already extracted.
  • The same product should also send your app's email and run support@ for people.

Who each is for

AgentMail describes itself as email inboxes for AI agents [6]. Its free plan gives 3 inboxes and 3,000 emails a month; custom domains start on the $20 Developer plan [1]. Pods and scoped keys serve platforms that give each of their own customers an inbox [4].

Mailbay is for agents and the apps around them. Each workspace gets a private {code}.mailbay.email domain where any address works through a Catch-all, so an agent can make up a new address per task without creating anything first. Projects, roles and inbox scoping cover teams; sending keys and SMTP cover app email.

Features and prices

Mailbay is in private beta and free while it runs. The Mailbay prices below are the planned plans from our pricing page; billing is not live yet.

FeatureMailbayAgentMail
Free plan3 inboxes, 3,000 emails a month, 3 custom domains3 inboxes, 3,000 emails a month, 100 a day, no custom domains [1]
First paid planPro, $9 a month: 25 inboxes, 50,000 emails, 10 domainsDeveloper, $20 a month: 10 inboxes, 10,000 emails, 10 domains [1]
Next planScale, $99 a month: 250 inboxes, 250,000 emails, unlimited domainsStartup, $200 a month: 150 inboxes, 150 domains [1]
Instant addresses without DNSAny address on your private mailbay.email code, with a Catch-allNot stated
Wait for an email, codes and links extractedYes: wait in the API, CLI and MCPNo dedicated endpoint documented; OTP sign ups are a listed use case
MCP serverRemote (API key) and stdioRemote with OAuth or API key, plus a stdio bridge [2]
SDKsNone yet; REST, CLI and MCPPython and Node [5]
IMAP and SMTPYes, with app passwords per inboxYes [3]
EventsStandard Webhooks and a WebSocketWebhooks and websockets [1]
Multi tenantProjects, workspace and project roles, inbox scoped keysPods and scoped keys [4]
Sending for apps from any verified addressYes: POST /v1/emails and SMTPSends from inboxes
Shared support inbox for peopleYes: assign, close, snooze, keyboard shortcutsNot stated
Compliance and regionsNot yetSOC 2 report on Startup; EU region on Enterprise [1]

Sources, read on October 14, 2026

  1. [1]AgentMail pricing: www.agentmail.to/pricing
  2. [2]AgentMail, MCP: docs.agentmail.to/integrations/mcp
  3. [3]AgentMail, IMAP and SMTP: docs.agentmail.to/imap-smtp
  4. [4]AgentMail, multi tenancy: docs.agentmail.to/multi-tenancy
  5. [5]AgentMail, API reference: docs.agentmail.to/api-reference
  6. [6]AgentMail home page: www.agentmail.to

Prices change. If something here is out of date or wrong, email hello@mailbay.dev and we will fix it.

Where AgentMail is better

  • It is further along. AgentMail is a paid product with SDKs, a SOC 2 report and enterprise options. Mailbay is in private beta.
  • SDKs. Typed Python and Node clients are nicer than raw HTTP. Mailbay has neither yet.
  • Breadth of agent features. AgentMail documents drafts, a calendar per inbox, reply extraction and allow and block lists. Mailbay does not have drafts or calendars.

Where Mailbay is better

  • Your domain, free. Add up to 3 custom domains on the free plan. If DNS is on Vercel or Cloudflare, Mailbay writes the records for you; elsewhere it checks each record live.
  • Fewer calls for sign ups. One blocking call returns the email with codes and links pulled out. No polling loop, no parsing. See the design notes.
  • Addresses cost nothing. run-4812@k7m3qz.mailbay.email works the moment you think of it, and the Catch-all does not count against your inbox limit.
  • One product for the whole company's email. The agent's inbox, the app's password reset emails and support@ live in the same project, under the same keys and roles.
  • Price. The planned Pro plan is $9 a month for 25 inboxes and 50,000 emails.

Moving from AgentMail

The concepts map closely, so most of a move is renaming calls. There is no import tool; old mail stays where it is.

  1. Inboxes: POST /v1/inboxes with a local_part, or skip creation entirely and use the Catch-all with a fresh address per run.
  2. Pods: create a project per tenant, or one project with an inbox key per agent, so a key can reach one inbox and nothing else.
  3. Webhooks: Mailbay signs with Standard Webhooks (webhook-id, webhook-timestamp, webhook-signature). Re-register your URL and update the verification step.
  4. MCP: swap the server URL in your client config. See give an MCP agent its own email.
An inbox and a code, two requests
curl https://api.mailbay.dev/v1/inboxes \
  -H "Authorization: Bearer $MAILBAY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"local_part": "signup"}'

curl "https://api.mailbay.dev/v1/inboxes/ibx_.../wait?timeout=60" \
  -H "Authorization: Bearer $MAILBAY_API_KEY"
# {"message": {...}, "codes": ["482913"], "links": ["https://example.com/verify?token=..."]}

Read next

Join the beta

Mailbay is in private beta and free while the beta runs: inboxes, sending, your own domains and MCP. We invite people in small batches and read every note on the form.

Join the betaRead the docs