Skip to main content
Resend logo

​
Overview

Add Resend to any ModuleX agent or workflow. Send transactional and marketing emails, retrieve email status, manage contacts, and view domains via the Resend REST API (api.resend.com).
Categories: Communication · Email · Email Marketing · Auth: API Key · Actions: 8

​
Authentication

​
API Key Authentication

Authenticate using your Resend API key
1

Step 1

Go to https://resend.com and sign up or log in
2

Step 2

Navigate to the ‘API Keys’ section in the dashboard
3

Step 3

Create a new API key (it starts with ‘re_’)
4

Step 4

Paste the API key below

​
Required Credentials

FieldDescriptionRequiredFormat
Resend API KeyYour Resend API key from resend.com/api-keysYesre_xxxxxxxxxxxxxxxxxxxxxxxxx

​
Available Actions

​
Parameters

​
from_address
string
required
Email address to send from (e.g. “sender@example.com” or “Sender Name <sender@example.com>”)
​
to
string
required
Recipient email address (e.g. “recipient@example.com” or “Recipient Name <recipient@example.com>”)
​
subject
string
required
Email subject line
​
body
string
required
Email body content (plain text or HTML based on content_type)
​
content_type
string
Content type for the body: “text” for plain text or “html” (Default: text)
​
cc
string
Carbon copy recipient email address
​
bcc
string
Blind carbon copy recipient email address
​
reply_to
string
Reply-to email address
​
scheduled_at
string
Schedule email to be sent later in ISO 8601 format
​
tags
string
Comma-separated key:value pairs for email tags (e.g. “category:welcome,type:onboarding”)

​
Response

{
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "id": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Id"
    },
    "to": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "To"
    },
    "subject": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Subject"
    },
    "body": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Body"
    }
  },
  "required": [
    "success"
  ],
  "title": "SendOutput",
  "type": "object"
}

​
Parameters

​
email_id
string
required
The ID of the email to retrieve

​
Response

{
  "$defs": {
    "EmailTag": {
      "additionalProperties": false,
      "description": "A single tag name/value pair attached to an email.",
      "properties": {
        "name": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Name"
        },
        "value": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Value"
        }
      },
      "title": "EmailTag",
      "type": "object"
    }
  },
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "id": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Id"
    },
    "sender": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Sender"
    },
    "to": {
      "items": {
        "type": "string"
      },
      "title": "To",
      "type": "array"
    },
    "subject": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Subject"
    },
    "html": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Html"
    },
    "text": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Text"
    },
    "cc": {
      "items": {
        "type": "string"
      },
      "title": "Cc",
      "type": "array"
    },
    "bcc": {
      "items": {
        "type": "string"
      },
      "title": "Bcc",
      "type": "array"
    },
    "reply_to": {
      "items": {
        "type": "string"
      },
      "title": "Reply To",
      "type": "array"
    },
    "last_event": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Last Event"
    },
    "created_at": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Created At"
    },
    "scheduled_at": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Scheduled At"
    },
    "tags": {
      "items": {
        "$ref": "#/$defs/EmailTag"
      },
      "title": "Tags",
      "type": "array"
    }
  },
  "required": [
    "success"
  ],
  "title": "GetEmailOutput",
  "type": "object"
}

​
Parameters

​
email
string
required
Email address of the contact
​
first_name
string
First name of the contact
​
last_name
string
Last name of the contact
​
unsubscribed
boolean
Whether the contact is unsubscribed from all broadcasts

​
Response

{
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "id": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Id"
    }
  },
  "required": [
    "success"
  ],
  "title": "CreateContactOutput",
  "type": "object"
}

​
Response

{
  "$defs": {
    "ContactItem": {
      "additionalProperties": false,
      "description": "A single contact row in ``list_contacts``.",
      "properties": {
        "id": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Id"
        },
        "email": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Email"
        },
        "first_name": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "First Name"
        },
        "last_name": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Last Name"
        },
        "created_at": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Created At"
        },
        "unsubscribed": {
          "anyOf": [
            {
              "type": "boolean"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Unsubscribed"
        }
      },
      "title": "ContactItem",
      "type": "object"
    }
  },
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "contacts": {
      "items": {
        "$ref": "#/$defs/ContactItem"
      },
      "title": "Contacts",
      "type": "array"
    },
    "has_more": {
      "anyOf": [
        {
          "type": "boolean"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Has More"
    }
  },
  "required": [
    "success"
  ],
  "title": "ListContactsOutput",
  "type": "object"
}

​
Parameters

​
contact_id
string
required
The contact ID or email address to retrieve

​
Response

{
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "id": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Id"
    },
    "email": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Email"
    },
    "first_name": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "First Name"
    },
    "last_name": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Last Name"
    },
    "created_at": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Created At"
    },
    "unsubscribed": {
      "anyOf": [
        {
          "type": "boolean"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Unsubscribed"
    }
  },
  "required": [
    "success"
  ],
  "title": "GetContactOutput",
  "type": "object"
}

​
Parameters

​
contact_id
string
required
The contact ID or email address to update
​
first_name
string
Updated first name
​
last_name
string
Updated last name
​
unsubscribed
boolean
Whether the contact should be unsubscribed from all broadcasts

​
Response

{
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "id": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Id"
    }
  },
  "required": [
    "success"
  ],
  "title": "UpdateContactOutput",
  "type": "object"
}

​
Parameters

​
contact_id
string
required
The contact ID or email address to delete

​
Response

{
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "id": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Id"
    },
    "deleted": {
      "anyOf": [
        {
          "type": "boolean"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Deleted"
    }
  },
  "required": [
    "success"
  ],
  "title": "DeleteContactOutput",
  "type": "object"
}

​
Response

{
  "$defs": {
    "DomainItem": {
      "additionalProperties": false,
      "description": "A single domain row in ``list_domains``.",
      "properties": {
        "id": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Id"
        },
        "name": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Name"
        },
        "status": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Status"
        },
        "region": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Region"
        },
        "created_at": {
          "anyOf": [
            {
              "type": "string"
            },
            {
              "type": "null"
            }
          ],
          "default": null,
          "title": "Created At"
        }
      },
      "title": "DomainItem",
      "type": "object"
    }
  },
  "additionalProperties": false,
  "properties": {
    "success": {
      "title": "Success",
      "type": "boolean"
    },
    "error": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Error"
    },
    "domains": {
      "items": {
        "$ref": "#/$defs/DomainItem"
      },
      "title": "Domains",
      "type": "array"
    },
    "has_more": {
      "anyOf": [
        {
          "type": "boolean"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "title": "Has More"
    }
  },
  "required": [
    "success"
  ],
  "title": "ListDomainsOutput",
  "type": "object"
}

​
Limits & Quotas

  • Rate limit: 2 requests/second by default (Resend account level).
  • Scheduling: emails can be scheduled up to 30 days ahead via scheduled_at (ISO 8601 timestamp).
  • Error model: non-2xx responses and timeouts are caught and returned as success=False + error rather than raising. Plan for retries on the agent side based on the error string.

AgentMail

Gmail

Mailgun