How do I install the Mailgun Email skill?

Run npx skillmds@latest add shakudo-io/mailgun-email in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

What does the Mailgun Email skill do?

Complete Mailgun integration for transactional email - send messages, manage templates, track delivery events, and handle suppressions via REST API. Use for sending emails, checking delivery status, managing bounces/unsubscribes, or automating email workflows. It is listed under Integrations & APIs on SkillMD.

Is Mailgun Email safe to use?

This skill has not completed SkillMD's automated safety review yet. Capability flags: makes network calls, reads secrets. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Mailgun Email?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Mailgun Email free to use?

Yes. Installing skills from SkillMD is free. This skill is licensed under MIT.

Who published Mailgun Email?

Shakudo-io (@shakudo-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Mailgun Email by shakudo-io — Agent Skill

Name: Mailgun Email
Rating: 4.2 (5 reviews)
Author: Shakudo-io

Mailgun Email Skill

Complete Mailgun REST API integration for transactional email, templates, delivery tracking, and suppression management.

Quick Start

# Load credentials
source /root/gitrepos/.claude/skills/mailgun-email/.env

# Send plain text email
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  --form-string "from=${MAILGUN_FROM_NAME} <${MAILGUN_FROM_EMAIL}>" \
  --form-string "to=recipient@example.com" \
  --form-string "subject=Hello from Mailgun" \
  --form-string "text=This is a test email."

# Send HTML email
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  --form-string "from=${MAILGUN_FROM_NAME} <${MAILGUN_FROM_EMAIL}>" \
  --form-string "to=recipient@example.com" \
  --form-string "subject=HTML Email" \
  --form-string "html=<html><body><h1>Hello</h1><p>This is HTML content.</p></body></html>"

IMPORTANT: Use --form-string instead of -F for text fields containing special characters like <> (e.g., email addresses in "Name " format, HTML content). The -F flag interprets < as file input which causes failures. Use -F only for file attachments (-F attachment=@/path/to/file).

Prerequisites & Authentication

Credentials Location

source /root/gitrepos/.claude/skills/mailgun-email/.env

Environment Variables

The .env file contains:

MAILGUN_API_KEY - API key for authentication
MAILGUN_DOMAIN - Sending domain (e.g., mg.shakudo.email)
MAILGUN_FROM_EMAIL - Default sender email
MAILGUN_FROM_NAME - Default sender name

Authentication

All API calls use HTTP Basic Auth with username api:

curl --user "api:${MAILGUN_API_KEY}" ...

Base URL

US Region: https://api.mailgun.net/v3
EU Region: https://api.eu.mailgun.net/v3

Shakudo uses US region.

Part 1: Sending Messages

Send Plain Text Email

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  --form-string "from=Sender Name <sender@${MAILGUN_DOMAIN}>" \
  --form-string "to=recipient@example.com" \
  --form-string "subject=Your Subject Here" \
  --form-string "text=Plain text body content here"

Response:

{
  "id": "<20260128120000.abc123@mg.shakudo.email>",
  "message": "Queued. Thank you."
}

Send HTML Email

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  --form-string "from=Sender Name <sender@${MAILGUN_DOMAIN}>" \
  --form-string "to=recipient@example.com" \
  --form-string "subject=HTML Email Subject" \
  --form-string "html=<html><body><h1>Welcome</h1><p>This is <strong>HTML</strong> content.</p></body></html>"

Send Both Text and HTML (Multipart)

Best practice - include both for email clients that don't render HTML:

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  --form-string "from=Sender <sender@${MAILGUN_DOMAIN}>" \
  --form-string "to=recipient@example.com" \
  --form-string "subject=Multipart Email" \
  --form-string "text=Plain text fallback for non-HTML clients" \
  --form-string "html=<html><body><h1>HTML Version</h1></body></html>"

Send with CC and BCC

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="primary@example.com" \
  -F cc="cc1@example.com" \
  -F cc="cc2@example.com" \
  -F bcc="hidden@example.com" \
  -F subject="Email with CC/BCC" \
  -F text="This email has CC and BCC recipients."

Send to Multiple Recipients

# Comma-separated in single field
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="user1@example.com, user2@example.com, user3@example.com" \
  -F subject="Bulk Email" \
  -F text="Message to multiple recipients."

# Or multiple -F to= flags
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="user1@example.com" \
  -F to="user2@example.com" \
  -F subject="Bulk Email" \
  -F text="Message to multiple recipients."

Send with Attachments

# Single attachment
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Email with Attachment" \
  -F text="Please see the attached file." \
  -F attachment=@/path/to/report.pdf

# Multiple attachments
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Multiple Attachments" \
  -F text="Multiple files attached." \
  -F attachment=@/path/to/file1.pdf \
  -F attachment=@/path/to/file2.xlsx

Send with Inline Images

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Email with Inline Image" \
  -F html='<html><body><h1>Logo</h1><img src="cid:logo.png"></body></html>' \
  -F inline=@/path/to/logo.png

Schedule Email for Later Delivery

# Send at specific time (RFC 2822 format, up to 7 days in future)
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Scheduled Email" \
  -F text="This was scheduled to arrive later." \
  -F o:deliverytime="Fri, 31 Jan 2026 09:00:00 -0500"

# Using Unix timestamp
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Scheduled Email" \
  -F text="Scheduled message." \
  -F o:deliverytime="1767180000"

Send with Tags (for Analytics)

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Tagged Email" \
  -F text="Email with tags for tracking." \
  -F o:tag="campaign-2026-01" \
  -F o:tag="newsletter"

Send with Tracking Options

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Tracked Email" \
  -F html="<html><body><a href='https://example.com'>Click here</a></body></html>" \
  -F o:tracking=yes \
  -F o:tracking-clicks=yes \
  -F o:tracking-opens=yes

Test Mode (Validate Without Sending)

# Process message but don't actually deliver
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Test Mode Email" \
  -F text="This will be validated but not sent." \
  -F o:testmode=yes

Send with Custom Headers

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Custom Headers" \
  -F text="Email with custom headers." \
  -F h:X-Custom-Header="custom-value" \
  -F h:Reply-To="reply@example.com"

Send with Recipient Variables (Mail Merge)

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="alice@example.com, bob@example.com" \
  -F subject="Hello %recipient.name%" \
  -F text="Dear %recipient.name%, your ID is %recipient.id%." \
  -F recipient-variables='{"alice@example.com": {"name": "Alice", "id": "A001"}, "bob@example.com": {"name": "Bob", "id": "B002"}}'

Python Example

import httpx

response = httpx.post(
    f"https://api.mailgun.net/v3/{MAILGUN_DOMAIN}/messages",
    auth=("api", MAILGUN_API_KEY),
    data={
        "from": f"{MAILGUN_FROM_NAME} <{MAILGUN_FROM_EMAIL}>",
        "to": "recipient@example.com",
        "subject": "Hello from Python",
        "html": "<html><body><h1>Hello!</h1></body></html>"
    }
)
print(response.json())

Sending Error Codes

Code	Meaning	Fix
400	Bad Request	Check required parameters (from, to, subject, text/html)
401	Unauthorized	Verify `MAILGUN_API_KEY` is correct
402	Payment Required	Account billing issue
404	Not Found	Verify `MAILGUN_DOMAIN` is active
413	Payload Too Large	Attachment exceeds 25MB limit
429	Too Many Requests	Rate limit hit (default 300/min), implement backoff

Part 2: Tracking & Events

Get Recent Events

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" | jq '.items[:5]'

Filter Events by Type

# Delivered emails
curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" \
  --data-urlencode "event=delivered" \
  --data-urlencode "limit=10"

# Failed/bounced emails
curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" \
  --data-urlencode "event=failed" \
  --data-urlencode "limit=10"

# Opens
curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" \
  --data-urlencode "event=opened" \
  --data-urlencode "limit=10"

# Clicks
curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" \
  --data-urlencode "event=clicked" \
  --data-urlencode "limit=10"

Filter Events by Recipient

curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" \
  --data-urlencode "recipient=user@example.com" \
  --data-urlencode "limit=20"

Filter Events by Date Range

# Events in last 24 hours
curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" \
  --data-urlencode "begin=$(date -d '24 hours ago' +%s)" \
  --data-urlencode "end=$(date +%s)" \
  --data-urlencode "limit=50"

Filter by Message ID

curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/events" \
  --data-urlencode "message-id=20260128120000.abc123@mg.shakudo.email"

Get Domain Stats

# Total stats
curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/stats/total" | jq '.'

# Stats with filters
curl -s --user "api:${MAILGUN_API_KEY}" \
  -G "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/stats/total" \
  --data-urlencode "event=delivered" \
  --data-urlencode "event=opened" \
  --data-urlencode "event=clicked" \
  --data-urlencode "duration=7d"

Event Types Reference

Event	Description
`accepted`	Message accepted by Mailgun
`delivered`	Message delivered to recipient's server
`failed`	Message could not be delivered (permanent)
`rejected`	Message rejected by Mailgun
`opened`	Recipient opened the email (requires tracking)
`clicked`	Recipient clicked a link (requires tracking)
`unsubscribed`	Recipient unsubscribed
`complained`	Recipient marked as spam
`stored`	Message stored for retrieval

Part 3: Templates

Create a Template

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/templates" \
  -F name="welcome-email" \
  -F description="Welcome email for new users" \
  -F template='<html><body><h1>Welcome, {{name}}!</h1><p>Thanks for joining us.</p></body></html>'

List Templates

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/templates" | jq '.items[] | {name, description}'

Get Template Details

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/templates/welcome-email" | jq '.'

Update a Template

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X PUT "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/templates/welcome-email" \
  -F description="Updated welcome email" \
  -F template='<html><body><h1>Welcome, {{name}}!</h1><p>We are glad to have you.</p></body></html>'

Delete a Template

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X DELETE "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/templates/welcome-email"

Send Using a Template

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Sender <sender@${MAILGUN_DOMAIN}>" \
  -F to="recipient@example.com" \
  -F subject="Welcome to Our Service" \
  -F template="welcome-email" \
  -F h:X-Mailgun-Variables='{"name": "John Doe"}'

Template Variables (Handlebars Syntax)

Templates use Handlebars syntax:

{{variable}} - Simple variable
{{#if condition}}...{{/if}} - Conditionals
{{#each items}}...{{/each}} - Loops

Part 4: Suppressions Management

Suppressions are addresses that should not receive emails (bounces, unsubscribes, complaints).

List Bounces

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/bounces" | jq '.items'

Get Bounce for Specific Address

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/bounces/bounced@example.com"

Add a Bounce (Manual Suppression)

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/bounces" \
  -F address="bad-address@example.com" \
  -F code="550" \
  -F error="Mailbox not found"

Delete a Bounce (Re-enable Sending)

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X DELETE "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/bounces/bad-address@example.com"

List Unsubscribes

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/unsubscribes" | jq '.items'

Add Unsubscribe

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/unsubscribes" \
  -F address="user@example.com" \
  -F tag="newsletter"

Delete Unsubscribe

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X DELETE "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/unsubscribes/user@example.com"

List Complaints (Spam Reports)

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/complaints" | jq '.items'

Add Complaint

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/complaints" \
  -F address="complainer@example.com"

Delete Complaint

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X DELETE "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/complaints/complainer@example.com"

Part 5: Domain Management

List Domains

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/domains" | jq '.items[] | {name, state, type}'

Get Domain Details

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/domains/${MAILGUN_DOMAIN}" | jq '.'

Verify Domain DNS

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X PUT "https://api.mailgun.net/v3/domains/${MAILGUN_DOMAIN}/verify"

Get Domain Credentials

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/domains/${MAILGUN_DOMAIN}/credentials"

Part 6: Mailing Lists

Create a Mailing List

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/lists" \
  -F address="newsletter@${MAILGUN_DOMAIN}" \
  -F name="Newsletter Subscribers" \
  -F description="Monthly newsletter list"

List All Mailing Lists

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/lists" | jq '.items[] | {address, name, members_count}'

Add Member to List

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/lists/newsletter@${MAILGUN_DOMAIN}/members" \
  -F subscribed=true \
  -F address="subscriber@example.com" \
  -F name="John Doe" \
  -F vars='{"age": 30, "city": "NYC"}'

Bulk Add Members

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/lists/newsletter@${MAILGUN_DOMAIN}/members.json" \
  -F members='[{"address":"user1@example.com","name":"User One"},{"address":"user2@example.com","name":"User Two"}]' \
  -F upsert=true

List Members

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/lists/newsletter@${MAILGUN_DOMAIN}/members?limit=100"

Remove Member

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X DELETE "https://api.mailgun.net/v3/lists/newsletter@${MAILGUN_DOMAIN}/members/subscriber@example.com"

Send to Mailing List

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/${MAILGUN_DOMAIN}/messages" \
  -F from="Newsletter <newsletter@${MAILGUN_DOMAIN}>" \
  -F to="newsletter@${MAILGUN_DOMAIN}" \
  -F subject="Monthly Newsletter" \
  -F html="<h1>Hello %recipient.name%!</h1><p>Your personalized content here.</p>"

Delete Mailing List

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X DELETE "https://api.mailgun.net/v3/lists/newsletter@${MAILGUN_DOMAIN}"

Part 7: Webhooks

Create Webhook

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/domains/${MAILGUN_DOMAIN}/webhooks" \
  -F id="delivered" \
  -F url="https://your-app.com/webhooks/mailgun/delivered"

List Webhooks

curl -s --user "api:${MAILGUN_API_KEY}" \
  "https://api.mailgun.net/v3/domains/${MAILGUN_DOMAIN}/webhooks" | jq '.'

Update Webhook

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X PUT "https://api.mailgun.net/v3/domains/${MAILGUN_DOMAIN}/webhooks/delivered" \
  -F url="https://your-app.com/webhooks/new-endpoint"

Delete Webhook

curl -s --user "api:${MAILGUN_API_KEY}" \
  -X DELETE "https://api.mailgun.net/v3/domains/${MAILGUN_DOMAIN}/webhooks/delivered"

Webhook Event Types

Event	Description
`accepted`	Message accepted by Mailgun
`delivered`	Message delivered successfully
`failed`	Delivery failed (permanent or temporary)
`opened`	Recipient opened email
`clicked`	Recipient clicked link
`unsubscribed`	Recipient unsubscribed
`complained`	Marked as spam

Verify Webhook Signature (Python)

import hmac
import hashlib

def verify_mailgun_webhook(timestamp, token, signature, api_key):
    """Verify Mailgun webhook signature"""
    message = f"{timestamp}{token}".encode('utf-8')
    computed = hmac.new(
        key=api_key.encode('utf-8'),
        msg=message,
        digestmod=hashlib.sha256
    ).hexdigest()
    return hmac.compare_digest(computed, signature)

Quick Reference

Endpoints Summary

Action	Method	Endpoint
Send Message	POST	`/{domain}/messages`
Get Events	GET	`/{domain}/events`
Get Stats	GET	`/{domain}/stats/total`
List Templates	GET	`/{domain}/templates`
Create Template	POST	`/{domain}/templates`
Delete Template	DELETE	`/{domain}/templates/{name}`
List Bounces	GET	`/{domain}/bounces`
Delete Bounce	DELETE	`/{domain}/bounces/{address}`
List Unsubscribes	GET	`/{domain}/unsubscribes`
List Complaints	GET	`/{domain}/complaints`
List Domains	GET	`/domains`
Get Domain	GET	`/domains/{domain}`
List Mailing Lists	GET	`/lists`
Create Mailing List	POST	`/lists`
List Members	GET	`/lists/{address}/members`
Add Member	POST	`/lists/{address}/members`
List Webhooks	GET	`/domains/{domain}/webhooks`
Create Webhook	POST	`/domains/{domain}/webhooks`

Message Parameters

Parameter	Required	Description
`from`	Yes	Sender address (must match domain)
`to`	Yes	Recipient(s), comma-separated or multiple fields
`subject`	Yes	Email subject line
`text`	One of	Plain text body
`html`	One of	HTML body
`cc`	No	Carbon copy recipients
`bcc`	No	Blind carbon copy recipients
`attachment`	No	File attachment(s)
`inline`	No	Inline image(s) for HTML
`o:tag`	No	Tag(s) for analytics
`o:deliverytime`	No	Scheduled delivery time
`o:tracking`	No	Enable tracking (yes/no)
`o:tracking-clicks`	No	Track clicks (yes/no/htmlonly)
`o:tracking-opens`	No	Track opens (yes/no)
`h:X-Custom-Header`	No	Custom headers (h: prefix)
`recipient-variables`	No	JSON for mail merge
`template`	No	Template name to use
`o:testmode`	No	Validate without sending (yes/no)

Rate Limits

Limit Type	Default
Messages per minute	300
Messages per day	Varies by plan
API calls per minute	100

Best Practices

Always include both text and HTML for better deliverability
Use tags for campaign tracking and analytics
Check suppressions before bulk sends to avoid bounces
Handle 429 errors with exponential backoff
Validate email addresses before sending
Use templates for consistent branding

Mailgun Email

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