How to Send Email from an AI Agent

You have built an AI agent that can reason, plan, and take actions. Now you need it to send an email. Maybe it needs to notify a customer, follow up on a lead, send a report, or respond to an incoming message. The problem is that most agent frameworks do not include email as a built-in capability.

This guide shows you how to send email from any AI agent using AgentSend. You will go from zero to sending your first agent email in under five minutes, with complete code examples in Python, Node.js, and cURL.

Step 1: Get Your API Key

Sign up for a free AgentSend account at agentsend.io/auth/signup. After signing up, you will find your API key in the dashboard. The free tier gives you 10 emails per day per inbox with no credit card required.

Step 2: Create an Inbox for Your Agent

Every agent needs its own email address. Create an inbox to get one:

curl -X POST https://agentsend.io/inboxes \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"name": "My AI Agent"}'

# Response:
# {
#   "inboxId": "inbox_abc123",
#   "email": "abc123@agentsend.io"
# }

Your agent now has an email address. Save the inboxId -- you will use it to send messages.

Step 3: Send Your First Email

With an inbox created, your agent can send emails immediately. Here are examples in three languages:

import requests

response = requests.post(
    "https://agentsend.io/messages",
    headers={
        "Authorization": "Bearer YOUR_API_KEY",
        "Content-Type": "application/json"
    },
    json={
        "inboxId": "inbox_abc123",
        "to": "recipient@example.com",
        "subject": "Hello from my AI agent",
        "text": "This email was sent by an autonomous AI agent."
    }
)

print(response.json())
# {"messageId": "msg_xyz789", "status": "sent"}

const response = await fetch('https://agentsend.io/messages', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    inboxId: 'inbox_abc123',
    to: 'recipient@example.com',
    subject: 'Hello from my AI agent',
    text: 'This email was sent by an autonomous AI agent.'
  })
});

const result = await response.json();
console.log(result);
// {messageId: "msg_xyz789", status: "sent"}

That is it. Three lines of meaningful code and your AI agent has sent an email. The recipient sees a normal email in their inbox -- they have no idea it was sent by an agent unless you tell them.

Step 4: Receive Replies via Webhook

Sending is only half the story. If the recipient replies, your agent needs to receive and process that reply. Update your inbox with a webhook URL:

curl -X PATCH https://agentsend.io/inboxes/inbox_abc123 \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"webhookUrl": "https://your-app.com/webhook/email"}'

Now when someone replies to your agent's email, AgentSend delivers the reply to your webhook as a JSON payload:

{
  "from": "recipient@example.com",
  "to": "abc123@agentsend.io",
  "subject": "Re: Hello from my AI agent",
  "text": "Thanks for reaching out! Can you tell me more?",
  "threadId": "thread_def456",
  "inboxId": "inbox_abc123"
}

Your agent processes the reply, generates a response, and sends it back using the same /messages endpoint. Include the threadId to keep the conversation in the same email thread.

Integrating with AI Agent Frameworks

AgentSend works with any AI framework. Here is how to add email as a tool in popular agent SDKs:

LangChain

Define a custom tool that calls the AgentSend API. Your LangChain agent can then decide when to send emails as part of its reasoning chain. See the LangChain integration guide for a complete example.

CrewAI

Give your CrewAI agents an email tool so crew members can communicate with external stakeholders. The sales researcher finds leads, the outreach agent emails them. See the CrewAI integration guide.

OpenAI Agents SDK

Register AgentSend as a function tool in your OpenAI agent. The agent calls it whenever it decides an email needs to be sent. See the OpenAI Agents integration guide.

Claude MCP

AgentSend is available as an MCP skill that Claude can use directly. Claude can create inboxes, send emails, and check for new messages as part of any conversation. See the Claude MCP integration guide.

Common Patterns

Outbound notifications

Your agent monitors a system and sends email alerts when something needs attention. A CI/CD agent emails the team when a build fails. A monitoring agent emails on-call when metrics exceed thresholds. A finance agent emails a summary of daily transactions.

Conversational workflows

Your agent sends an initial email and handles the back-and-forth. A sales agent sends a cold email, handles objections in the reply, and books a meeting. A support agent asks clarifying questions before providing a solution.

Scheduled reports

Your agent compiles data and emails a formatted report on a schedule. Daily analytics summaries, weekly team updates, monthly investor reports -- all composed and sent by your agent.

Multi-agent collaboration

Multiple agents communicate via email. A research agent emails its findings to an analysis agent, which emails a summary to a reporting agent. Each agent has its own inbox and processes messages independently.