Resend

Resend

Access the Resend API with managed authentication. Send transactional emails, manage domains, contacts, templates, broadcasts, and webhooks.

Quick Start

# List sent emails
python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/emails')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Base URL

https://gateway.maton.ai/resend/{endpoint}

The gateway proxies requests to api.resend.com and automatically injects your API key.

Authentication

All requests require the Maton API key in the Authorization header:

Authorization: Bearer $MATON_API_KEY

Environment Variable: Set your API key as MATON_API_KEY:

export MATON_API_KEY="YOUR_API_KEY"

Getting Your API Key

1. Sign in or create an account at maton.ai
2. Go to maton.ai/settings
3. Copy your API key

Connection Management

Manage your Resend connections at https://ctrl.maton.ai.

List Connections

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections?app=resend&status=ACTIVE')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create Connection

python <<'EOF'
import urllib.request, os, json
data = json.dumps({'app': 'resend'}).encode()
req = urllib.request.Request('https://ctrl.maton.ai/connections', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Get Connection

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections/{connection_id}')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Response:

{
  "connection": {
    "connection_id": "528c8f70-23f4-46d5-bd9f-01d0d043e573",
    "status": "ACTIVE",
    "creation_time": "2026-03-13T00:19:36.809599Z",
    "last_updated_time": "2026-03-13T09:59:08.443568Z",
    "url": "https://connect.maton.ai/?session_token=...",
    "app": "resend",
    "metadata": {},
    "method": "API_KEY"
  }
}

Delete Connection

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections/{connection_id}', method='DELETE')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Specifying Connection

If you have multiple Resend connections, specify which one to use with the Maton-Connection header:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/emails')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Maton-Connection', '528c8f70-23f4-46d5-bd9f-01d0d043e573')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

If omitted, the gateway uses the default (oldest) active connection.

API Reference

Emails

Send and manage transactional emails.

Send Email

POST /resend/emails

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({
    'from': 'you@yourdomain.com',
    'to': ['recipient@example.com'],
    'subject': 'Hello from Resend',
    'html': '<p>Welcome to our service!</p>'
}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/emails', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Request Body:

Response:

{
  "id": "a52ac168-338f-4fbc-9354-e6049b193d99"
}

Send Batch Emails

POST /resend/emails/batch

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps([
    {'from': 'you@yourdomain.com', 'to': ['a@example.com'], 'subject': 'Email 1', 'text': 'Content 1'},
    {'from': 'you@yourdomain.com', 'to': ['b@example.com'], 'subject': 'Email 2', 'text': 'Content 2'}
]).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/emails/batch', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

List Emails

GET /resend/emails

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/emails')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Response:

{
  "data": [
    {
      "id": "a52ac168-338f-4fbc-9354-e6049b193d99",
      "from": "you@yourdomain.com",
      "to": ["recipient@example.com"],
      "subject": "Hello from Resend",
      "created_at": "2026-03-13T10:00:00.000Z"
    }
  ]
}

Get Email

GET /resend/emails/{email_id}

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/emails/{email_id}')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Update Email

PATCH /resend/emails/{email_id}

Cancel Scheduled Email

DELETE /resend/emails/{email_id}

Domains

Manage sending domains.

List Domains

GET /resend/domains

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/domains')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Response:

{
  "data": [
    {
      "id": "5eb93a2e-e849-40a1-81b7-ed0fb574ddd8",
      "name": "yourdomain.com",
      "status": "verified",
      "created_at": "2026-03-13T10:00:00.000Z"
    }
  ]
}

Create Domain

POST /resend/domains

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({'name': 'yourdomain.com'}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/domains', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Response:

{
  "id": "5eb93a2e-e849-40a1-81b7-ed0fb574ddd8",
  "name": "yourdomain.com",
  "status": "pending",
  "records": [
    {"type": "MX", "name": "...", "value": "..."},
    {"type": "TXT", "name": "...", "value": "..."}
  ]
}

Get Domain

GET /resend/domains/{domain_id}

Update Domain

PATCH /resend/domains/{domain_id}

Delete Domain

DELETE /resend/domains/{domain_id}

Verify Domain

POST /resend/domains/{domain_id}/verify

Contacts

Manage contact lists.

List Contacts

GET /resend/contacts

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/contacts')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create Contact

POST /resend/contacts

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({
    'email': 'contact@example.com',
    'first_name': 'John',
    'last_name': 'Doe'
}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/contacts', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Response:

{
  "id": "3cdc4bbb-0c79-46e5-be2a-48a89c29203d"
}

Get Contact

GET /resend/contacts/{contact_id}

Update Contact

PATCH /resend/contacts/{contact_id}

Delete Contact

DELETE /resend/contacts/{contact_id}

Templates

Manage email templates.

List Templates

GET /resend/templates

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/templates')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create Template

POST /resend/templates

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({
    'name': 'Welcome Email',
    'subject': 'Welcome to our service!',
    'html': '<h1>Welcome!</h1><p>Thanks for signing up.</p>'
}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/templates', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Response:

{
  "id": "9b84737c-8a80-448a-aca1-c6e1fddd0f23"
}

Get Template

GET /resend/templates/{template_id}

Update Template

PATCH /resend/templates/{template_id}

Delete Template

DELETE /resend/templates/{template_id}

Publish Template

POST /resend/templates/{template_id}/publish

Duplicate Template

POST /resend/templates/{template_id}/duplicate

Segments

Create audience segments for targeting.

List Segments

GET /resend/segments

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/segments')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create Segment

POST /resend/segments

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({
    'name': 'Active Users',
    'filter': {
        'and': [
            {'field': 'email', 'operator': 'contains', 'value': '@'}
        ]
    }
}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/segments', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Get Segment

GET /resend/segments/{segment_id}

Delete Segment

DELETE /resend/segments/{segment_id}

Broadcasts

Send emails to segments.

List Broadcasts

GET /resend/broadcasts

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/broadcasts')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create Broadcast

POST /resend/broadcasts

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({
    'name': 'Weekly Newsletter',
    'from': 'newsletter@yourdomain.com',
    'subject': 'This Week's Update',
    'html': '<h1>Weekly Update</h1><p>Here's what happened...</p>',
    'segment_id': 'segment-uuid'
}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/broadcasts', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Get Broadcast

GET /resend/broadcasts/{broadcast_id}

Update Broadcast

PATCH /resend/broadcasts/{broadcast_id}

Delete Broadcast

DELETE /resend/broadcasts/{broadcast_id}

Send Broadcast

POST /resend/broadcasts/{broadcast_id}/send

Webhooks

Configure event notifications.

List Webhooks

GET /resend/webhooks

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/webhooks')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create Webhook

POST /resend/webhooks

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({
    'endpoint': 'https://yoursite.com/webhook',
    'events': ['email.delivered', 'email.bounced', 'email.opened']
}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/webhooks', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Webhook Events:

• email.sent - Email was sent
• email.delivered - Email was delivered
• email.opened - Email was opened
• email.clicked - Link in email was clicked
• email.bounced - Email bounced
• email.complained - Recipient marked as spam

Get Webhook

GET /resend/webhooks/{webhook_id}

Update Webhook

PATCH /resend/webhooks/{webhook_id}

Delete Webhook

DELETE /resend/webhooks/{webhook_id}

API Keys

Manage API keys.

List API Keys

GET /resend/api-keys

Example:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://gateway.maton.ai/resend/api-keys')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create API Key

POST /resend/api-keys

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({'name': 'Production Key'}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/api-keys', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Note: The actual API key value is only returned once on creation.

Delete API Key

DELETE /resend/api-keys/{api_key_id}

Topics

Manage subscription topics.

List Topics

GET /resend/topics

Create Topic

POST /resend/topics

Example:

python <<'EOF'
import urllib.request, os, json
data = json.dumps({
    'name': 'Newsletter',
    'default_subscription': 'subscribed'
}).encode()
req = urllib.request.Request('https://gateway.maton.ai/resend/topics', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Note: default_subscription is required. Values: subscribed or unsubscribed.

Get Topic

GET /resend/topics/{topic_id}

Update Topic

PATCH /resend/topics/{topic_id}

Delete Topic

DELETE /resend/topics/{topic_id}

Contact Properties

Manage custom contact properties.

List Contact Properties

GET /resend/contact-properties

Create Contact Property

POST /resend/contact-properties

Get Contact Property

GET /resend/contact-properties/{property_id}

Update Contact Property

PATCH /resend/contact-properties/{property_id}

Delete Contact Property

DELETE /resend/contact-properties/{property_id}

Code Examples

JavaScript

// Send an email
const response = await fetch('https://gateway.maton.ai/resend/emails', {
  method: 'POST',
  headers: {
    'Authorization': `Bearer ${process.env.MATON_API_KEY}`,
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    from: 'you@yourdomain.com',
    to: ['recipient@example.com'],
    subject: 'Hello!',
    html: '<p>Welcome!</p>'
  })
});
const data = await response.json();
console.log(data.id);

Python

import os
import requests

response = requests.post(
    'https://gateway.maton.ai/resend/emails',
    headers={
        'Authorization': f'Bearer {os.environ["MATON_API_KEY"]}',
        'Content-Type': 'application/json'
    },
    json={
        'from': 'you@yourdomain.com',
        'to': ['recipient@example.com'],
        'subject': 'Hello!',
        'html': '<p>Welcome!</p>'
    }
)
email = response.json()
print(f"Email sent: {email['id']}")

Notes

• Sending emails requires a verified domain
• Rate limit: 2 requests per second
• Batch emails accept up to 100 emails per request
• Scheduled emails can be set up to 7 days in advance
• Attachments support base64 encoded content or URLs
• The from address must use a verified domain
• IMPORTANT: When piping curl output to jq or other commands, environment variables like $MATON_API_KEY may not expand correctly in some shell environments

Error Handling

Troubleshooting: API Key Issues

1. Check that the MATON_API_KEY environment variable is set:

echo $MATON_API_KEY

2. Verify the API key is valid by listing connections:

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Troubleshooting: Domain Not Verified

To send emails, you must first add and verify a domain:

1. Create a domain: POST /resend/domains
2. Add the DNS records provided in the response
3. Verify the domain: POST /resend/domains/{id}/verify

Resources

• Resend API Documentation
• Resend Dashboard
• Maton Community
• Maton Support