AI agent inboxes
Give each AI agent its own address on your domain, next to your team. It writes to people it knows on its own, asks a person before writing to anyone new, never reads spoofed mail, and says it's an AI. Included with every seat.
Works over the REST API and MCP. See how it compares with AgentMail
Waiting for approval
Held from the agent
Its email to someone new waits for a person, exactly as it would go out. Mail that fails sender checks never reaches it.
01 What it is
An agent inbox is a mailbox on your own domain, next to your team's, with rules on from the start. Its key reaches that inbox and nothing else.
billing@, support@ or bookings@ on your verified domain, beside your team's mailboxes. Its mail shows in the app for the person who answers for it.
The agent's key reaches its own inbox and nothing else in your workspace. Give it an expiry, and revoke it whenever you like.
Replies, and email to people it already writes with, go out on their own. Email to someone new waits until a person approves it, exactly as written.
We check who really sent each email to an agent. Mail that fails, or comes from a sender you've blocked, waits for a person to release it.
Text hidden in an email, by styling or by trickery, is removed before the agent reads it, and every message says how far its sender can be trusted.
Every email it sends ends with a line naming the agent and the person it works for, the kind of disclosure the EU AI Act asks for. Only an admin can turn it off.
One spam complaint, or three bounced addresses, on its mail in 24 hours pauses that agent, on stricter limits than your team's. You can pause it yourself at any time.
Create inboxes and keys over the REST API, work the inbox over the API or MCP, and hear about new, held and waiting mail through signed webhooks.
02 How it works
Nothing to install and no server to run: an address, a key, and the rules it works by.
Give it a name, an address on your domain and the person it works for, in Settings → Agents or with one API call.
Put the key in your code or your MCP client. The agent works its own inbox: reading, replying and sending, and nothing else.
Ask for new people (the default), ask every time, or send within daily limits. The rules belong to the inbox, so they hold whichever key sends.
03 What teams use it for
Agents do best on mail that comes in steadily and follows a pattern, with a person a click away.
support@
Answers the questions it has seen before, and drafts first replies to new customers for a person to approve.
invoices@
Reads what suppliers send, keeps it in order, and asks before writing to an address it doesn't know.
bookings@
Proposes times, then confirms and reschedules meetings by email, from an address of its own.
sales@
Follows up with people who wrote in. Its first email to anyone new waits for a person.
04 Price
A five-person team on Business pays $30 a month, or $25 a month billed yearly, for five mailboxes and 25 agent inboxes. The same 25 agent inboxes on their own are $50 a month at AgentMail’s list prices, checked 16 Oct 2026.
Agent inboxes never count as paid seats. Need more? Each seat you add brings its share.
05 For developers
Create agent inboxes and their keys over the REST API, then work the inbox over the API or MCP. Every endpoint is in the API reference.
curl -X POST "https://supermailos.com/api/v1/inboxes" \
-H "Authorization: Bearer $SUPERMAILOS_API_KEY" \
-H "Content-Type: application/json" \
-d '{"name": "Billing assistant", "createKey": true}'claude mcp add --transport http \ billing-assistant https://supermailos.com/mcp \ --header "Authorization: Bearer $AGENT_KEY"
06 Questions
Something else? Write to us — a real person answers, usually the same day.
14 days free with 3 agent inboxes. No card, and your domain stays yours.