> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agentruntime.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Resend connector

> Send transactional email and manage audiences from AgentRuntime workflows.

The **resend** MCP adapter integrates [Resend](https://resend.com) for reliable transactional email. Use it to notify users when workflows finish, send reports, and drive onboarding sequences — with a verified sender domain.

## Prerequisites

* A Resend account with a **verified domain** (or Resend's test domain for development)
* A Resend **API key** with send permissions
* A default **From** address on that verified domain
* **project\_contributor** access

## Connect in AgentRuntime

<Steps>
  <Step title="Verify your domain in Resend">
    In the Resend dashboard, add DNS records for your sending domain and wait for verification.
  </Step>

  <Step title="Create a connection">
    Go to **Connections**, click **New custom connection**, and create an API key connection, and paste your Resend API key. Optionally set `FromEmail` in the connection or MCP config profile.
  </Step>

  <Step title="Add resend MCP instance">
    Go to **MCP**, click **Add instance** for **resend**, wire your connection on **Instance config**, set the profile **active**, and save.
  </Step>

  <Step title="Send a test email">
    Run a workflow with **mcp\_call** → `send_email` to yourself before wiring production notifications.
  </Step>
</Steps>

## What you can build

* **Workflow completion alerts** — After a run succeeds or fails, `send_email` with run ID, step summary, and a link to Command Center.
* **Weekly digest** — Postgres `postgres_query` for metrics → LLM narrative → `send_email` to stakeholders.
* **Human task reminders** — When a **human\_task** is assigned, email the assignee with task title and due date.
* **Audience sync reporting** — `list_audiences` to verify list IDs before syncing contacts from ActiveCampaign or a form webhook.

## Tools

| Tool             | Description                           |
| ---------------- | ------------------------------------- |
| `send_email`     | Send an email through Resend          |
| `list_audiences` | List audiences visible to the API key |

## Example

```json theme={null}
{
  "id": "notify-complete",
  "type": "mcp_call",
  "name": "Email run summary",
  "tool_name": "send_email",
  "tool_args": {
    "to": "ops@example.com",
    "subject": "Workflow finished: {{input.workflow_name}}",
    "html": "<p>Run <strong>{{input.run_id}}</strong> completed.</p>"
  },
  "timeout_s": 30
}
```

## Configuration

| Key          | Required | Description                                            |
| ------------ | -------- | ------------------------------------------------------ |
| `APIKey`     | Yes      | Resend API key                                         |
| `FromEmail`  | Yes      | Verified sender address (default From on `send_email`) |
| `APIBase`    | No       | Resend API base URL (default production endpoint)      |
| `AudienceID` | No       | Default audience for list/subscription tools           |

## Troubleshooting

| Issue               | Fix                                                                      |
| ------------------- | ------------------------------------------------------------------------ |
| Domain not verified | Complete DNS verification in Resend before sending to external addresses |
| `403` on send       | From address must use a verified domain; check `FromEmail` in config     |
| Emails in spam      | Configure SPF, DKIM, and DMARC for your sending domain                   |

## Related

* [Integrations quickstart](/integrations/quickstart)
* [Gmail connector](/connectors/gmail) — send from a user's Google mailbox instead
* [Connector catalog](/integrations/connector-catalog)
* [Troubleshooting](/platform/troubleshooting)