AI Email Address — What a .ai Inbox Is and How It Works

What is a .ai email address?

A .ai email address is a mailbox on the .ai top-level domain — the same TLD used by Mails.ai itself. Unlike a traditional email address that a person manages, a .ai email address belongs to a program: an AI email agent that sends transactional or conversational mail and processes every reply automatically. Because it sits on a domain operated for this purpose, SPF, DKIM and DMARC are pre-aligned and sender reputation is tracked per-agent from the first send.

The address is created by sending, not by provisioning

Normally getting a mailbox means a licence, an admin console and DNS records. Here the first send creates it. Name the address you want in from and it exists, with a receiving address alongside it. A workspace starts with one, hello; naming another, as here, needs Pro (5 agents):

curl -X POST https://api.mails.ai/v1/messages \
  -H "Authorization: Bearer $MAILS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "from": "support",
    "to": "customer@example.com",
    "subject": "Your invoice #221 is ready",
    "body_text": "Invoice #221 for March is attached, due the 30th."
  }'

# sends from  support.yourworkspace@send.mails.ai
# receives at support.yourworkspace@in.mails.ai

Deliverable, because the domain is operated rather than resold

An address is only worth having if mail from it arrives. SPF, DKIM and DMARC are aligned on the shared domain because we run it, and the estate stays clean because every send is checked before it leaves. Every address carries its own reputation score and auto-suspends at a 0.3% complaint rate — before an upstream provider’s 0.5% line is reached.

Receiving is the half that makes it an address

Mail sent to the receiving address is parsed, threaded, scanned for prompt injection and delivered to your code as an event — clean text body, sender, thread id, and an injection_score on every one. Replies from your agent reuse the Message-ID chain, so they appear inside the existing conversation in the recipient’s client rather than as a new thread. See the inbound email API page for the full receiving flow.

Cost

Free: 3,000 emails and 3,000 inbound replies a month, one agent, no card. Then Pro at $20 a month for 50,000 emails and 50,000 inbound replies, or Scale at $99 for 250,000 emails and 500,000 inbound replies — parsing and the injection scan included. Need to send from your own domain? See custom domain email for AI agents.