Email for AI customer support agents
Your support agent needs to receive the customer’s email, understand it, and reply. Send-only email APIs stop at outbound.
Sendmux gives the agent a real mailbox. It receives email, reads it clean, replies from the same address, and won’t get suspended mid-conversation.
<TL;DR for AI agents>
The support loop an agent can read.
What the agent gets
- Give one agent a scoped mailbox. It receives, reads clean, replies, and labels, over REST or MCP.
- Listen for new mail on a live event stream. No polling loop.
- Read the question without the quoted history. Fewer tokens per ticket.
One scoped credential covers the whole loop: receive, read, reply, and label.
# Wake on a new customer email $ curl -N "https://app.sendmux.ai/api/v1/mailbox/events?event_types=message.received" \ -H "Authorization: Bearer smx_mbx_your_key" # Read it clean: no quoted history, no signature $ curl "https://app.sendmux.ai/api/v1/mailbox/messages/msg_123/content ?strip_quotes=true&strip_signature=true" \ -H "Authorization: Bearer smx_mbx_your_key"
How it works
One mailbox, the whole loop.
A customer emails your agent. Sendmux hands it the message, the reply path, and the labels. Here is the whole loop.
A live event fires the moment a customer emails, so your agent reacts without polling an inbox on a timer.
Sendmux strips quotes and signatures so the agent reads the question, then sends the reply from the same address.
The agent labels the thread, files it in a folder, and sender rules keep the spam out of the support queue.
Clean content
Read the email, not the noise.
Customer emails arrive with quoted history, signatures, and footers. Sendmux returns clean JSON, so your agent reads the question and spends fewer tokens on every ticket.
Raw email · ticket 4821
{
"text": "Where is my refund for order 4821? It has been two weeks.",
"quotes_stripped": false,
"signature_stripped": false,
"extracted_links": []
}- Strips quoted history and signatures from every message.
- Pulls links into a typed array your agent can act on.
- Caps body length so a long thread never blows your context.
- Returns attachment metadata; the bytes stay one call away.
Control the queue
Filter the noise, scope the key.
A public support address attracts spam and cost. Sender rules keep it out, and a mailbox-scoped key keeps the agent boxed to its own inbox.
Scoped key
A key boxed to one mailbox
The agent uses a mailbox credential that only reaches its own inbox. Team-wide keys are rejected here, so it can never read another mailbox. Or connect over MCP and skip static keys.
# One credential, one mailbox. Team keys are rejected here. $ curl https://app.sendmux.ai/api/v1/mailbox/me \ -H "Authorization: Bearer smx_mbx_support_agent_key"
Sender rules
Keep spam out of the queue
Set the mailbox to allow or deny by sender. Rejected mail never reaches the agent, and it is not billed, so a public address stays cheap and quiet.
- Allowlist or denylist senders by address or pattern.
- Spam lands on its own event, kept out of the main flow.
- Mail rejected by a rule is free, no charge for noise.
- Rules read back in order, so the agent sees a stable queue.
1,800/min
sends per mailbox
100per call
messages labelled
$0.15/1k
inbound email
10M+/day
load-tested
Common questions
What support teams ask first.
Yes. Send the reply from the agent’s mailbox and Sendmux groups it into the conversation automatically, by Message-ID and References. Your agent can read the full thread as clean, paginated content before it writes.
Read message or thread content through the clean endpoint. It strips quoted history and signatures, pulls links into an array, and caps the body length, so the agent reads the question and not the noise.
Yes. Set your own keyword labels and flags on up to 100 messages in one call, and move messages between folders. Labels are plain strings you choose, like refund_request or escalated.
No. Sendmux is the email layer, not the agent. It gives your agent the mailbox, clean content, labels, folders, and sender rules. Your agent’s model decides what each email means and how to answer.
Set sender rules to allow or deny by address or pattern. Rejected mail never reaches the agent, and mail blocked by a rule is not billed, so a public address stays cheap under a spam burst.
Yes. Run the mailbox on your own verified domain with guided DNS, or start instantly on a shared @myagent.mx address. For outbound, route through your own providers or the managed Amazon SES account.
Email for AI customer support agents
Give your support agent a mailbox that lasts.
Real address, clean content, and labels. Usage-based, no per-mailbox fee, and nothing that gets suspended mid-conversation.