name: resend description: Resend email API via curl. Use this skill to send transactional emails, manage contacts, domains, and API keys. vm0_secrets:

RESEND_API_KEY

Resend Email API

Send transactional emails, manage contacts, and domains via Resend's REST API.

Official docs: https://resend.com/docs/api-reference/introduction

When to Use

Use this skill when you need to:

Send transactional emails (welcome, password reset, notifications)
Send batch emails to multiple recipients
Manage email contacts and audiences
Verify and manage sending domains
Track email delivery status

Prerequisites

Sign up at https://resend.com
Go to API Keys: https://resend.com/api-keys
Create a new API key

Set environment variable:

export RESEND_API_KEY="re_xxxxxxxxx"

Important: When using $VAR in a command that pipes to another command, wrap the command containing $VAR in bash -c '...'. Due to a Claude Code bug, environment variables are silently cleared when pipes are used directly.

Placeholders: Values in {curly-braces} like {email-id} are placeholders. Replace them with actual values when executing.

Emails

Send Email

Write to /tmp/resend_request.json:

{
  "from": "Acme <onboarding@resend.dev>",
  "to": ["<your-recipient-email>"],
  "subject": "<your-subject>",
  "html": "<p><your-html-content></p>"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/emails" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Send Email with Plain Text

Write to /tmp/resend_request.json:

{
  "from": "Acme <onboarding@resend.dev>",
  "to": ["<your-recipient-email>"],
  "subject": "<your-subject>",
  "text": "<your-plain-text-content>"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/emails" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Send Email with CC/BCC

Write to /tmp/resend_request.json:

{
  "from": "Acme <onboarding@resend.dev>",
  "to": ["<your-recipient-email>"],
  "cc": ["<your-cc-email>"],
  "bcc": ["<your-bcc-email>"],
  "subject": "<your-subject>",
  "html": "<p><your-html-content></p>"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/emails" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Send Email with Reply-To

Write to /tmp/resend_request.json:

{
  "from": "Acme <onboarding@resend.dev>",
  "to": ["<your-recipient-email>"],
  "replyTo": "<your-reply-to-email>",
  "subject": "<your-subject>",
  "html": "<p><your-html-content></p>"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/emails" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Send Scheduled Email

Schedule email using natural language or ISO 8601 format:

Write to /tmp/resend_request.json:

{
  "from": "Acme <onboarding@resend.dev>",
  "to": ["<your-recipient-email>"],
  "subject": "<your-subject>",
  "html": "<p><your-html-content></p>",
  "scheduledAt": "in 1 hour"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/emails" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Send Batch Emails

Send up to 100 emails in a single request:

Write to /tmp/resend_request.json:

[
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["<your-recipient-1>"],
    "subject": "Hello 1",
    "html": "<p>Email 1</p>"
  },
  {
    "from": "Acme <onboarding@resend.dev>",
    "to": ["<your-recipient-2>"],
    "subject": "Hello 2",
    "html": "<p>Email 2</p>"
  }
]

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/emails/batch" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Retrieve Email

bash -c 'curl -s "https://api.resend.com/emails/<your-email-id>" --header "Authorization: Bearer $RESEND_API_KEY"'

List Sent Emails

bash -c 'curl -s "https://api.resend.com/emails" --header "Authorization: Bearer $RESEND_API_KEY"'

Cancel Scheduled Email

bash -c 'curl -s -X POST "https://api.resend.com/emails/<your-email-id>/cancel" --header "Authorization: Bearer $RESEND_API_KEY"'

Contacts

Create Contact

Write to /tmp/resend_request.json:

{
  "email": "<your-contact-email>",
  "firstName": "<your-first-name>",
  "lastName": "<your-last-name>",
  "unsubscribed": false
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/contacts" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Create Contact with Custom Properties

Write to /tmp/resend_request.json:

{
  "email": "<your-contact-email>",
  "firstName": "<your-first-name>",
  "lastName": "<your-last-name>",
  "properties": {
    "company": "<your-company-name>",
    "role": "<your-role>"
  }
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/contacts" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Retrieve Contact

bash -c 'curl -s "https://api.resend.com/contacts/<your-contact-id>" --header "Authorization: Bearer $RESEND_API_KEY"'

List Contacts

bash -c 'curl -s "https://api.resend.com/contacts" --header "Authorization: Bearer $RESEND_API_KEY"'

List Contacts with Pagination

bash -c 'curl -s "https://api.resend.com/contacts?limit=50" --header "Authorization: Bearer $RESEND_API_KEY"'

Update Contact

Write to /tmp/resend_request.json:

{
  "firstName": "<your-new-first-name>",
  "unsubscribed": true
}

Then run:

bash -c 'curl -s -X PATCH "https://api.resend.com/contacts/<your-contact-id>" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Delete Contact

bash -c 'curl -s -X DELETE "https://api.resend.com/contacts/<your-contact-id>" --header "Authorization: Bearer $RESEND_API_KEY"'

Domains

List Domains

bash -c 'curl -s "https://api.resend.com/domains" --header "Authorization: Bearer $RESEND_API_KEY"'

Retrieve Domain

bash -c 'curl -s "https://api.resend.com/domains/<your-domain-id>" --header "Authorization: Bearer $RESEND_API_KEY"'

Create Domain

Write to /tmp/resend_request.json:

{
  "name": "<your-domain-name>"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/domains" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Verify Domain

bash -c 'curl -s -X POST "https://api.resend.com/domains/<your-domain-id>/verify" --header "Authorization: Bearer $RESEND_API_KEY"'

Delete Domain

bash -c 'curl -s -X DELETE "https://api.resend.com/domains/<your-domain-id>" --header "Authorization: Bearer $RESEND_API_KEY"'

API Keys

List API Keys

bash -c 'curl -s "https://api.resend.com/api-keys" --header "Authorization: Bearer $RESEND_API_KEY"'

Create API Key

Write to /tmp/resend_request.json:

{
  "name": "<your-key-name>"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/api-keys" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Create API Key with Permissions

Write to /tmp/resend_request.json:

{
  "name": "<your-key-name>",
  "permission": "sending_access"
}

Then run:

bash -c 'curl -s -X POST "https://api.resend.com/api-keys" --header "Authorization: Bearer $RESEND_API_KEY" --header "Content-Type: application/json" -d @/tmp/resend_request.json'

Delete API Key

bash -c 'curl -s -X DELETE "https://api.resend.com/api-keys/<your-api-key-id>" --header "Authorization: Bearer $RESEND_API_KEY"'

Email Parameters Reference

Parameter	Type	Description
`from`	string	Sender email (required). Format: `"Name <email@domain.com>"`
`to`	string[]	Recipients (required). Max 50 addresses
`subject`	string	Email subject (required)
`html`	string	HTML content
`text`	string	Plain text content
`cc`	string[]	CC recipients
`bcc`	string[]	BCC recipients
`replyTo`	string	Reply-to address
`scheduledAt`	string	Schedule time (ISO 8601 or natural language)
`tags`	array	Custom tags for tracking
`attachments`	array	File attachments (max 40MB total)

Response Codes

Status	Description
`200`	Success
`400`	Invalid parameters
`401`	Missing API key
`403`	Invalid API key
`404`	Resource not found
`429`	Rate limit exceeded (2 req/sec)
`5xx`	Server error

Guidelines

Rate Limits: Default is 2 requests per second; implement backoff for 429 errors
Sender Domain: Use verified domains for production; onboarding@resend.dev for testing
Batch Emails: Use /emails/batch for sending to multiple recipients efficiently
Idempotency: Use Idempotency-Key header to prevent duplicate sends
Scheduling: Use natural language (in 1 hour) or ISO 8601 format for scheduledAt

API Reference

Documentation: https://resend.com/docs/api-reference/introduction
Dashboard: https://resend.com/overview
API Keys: https://resend.com/api-keys
Domains: https://resend.com/domains

Name	resend
Description	Resend email API via curl. Use this skill to send transactional emails, manage contacts, domains, and API keys.

resend

SKILL.md

Resend Email API

When to Use

Prerequisites

Emails

Send Email

Send Email with Plain Text

Send Email with CC/BCC

Send Email with Reply-To

Send Scheduled Email

Send Batch Emails

Retrieve Email

List Sent Emails

Cancel Scheduled Email

Contacts

Create Contact

Create Contact with Custom Properties

Retrieve Contact

List Contacts

List Contacts with Pagination

Update Contact

Delete Contact

Domains

List Domains

Retrieve Domain

Create Domain

Verify Domain

Delete Domain

API Keys

List API Keys

Create API Key

Create API Key with Permissions

Delete API Key

Email Parameters Reference

Response Codes

Guidelines

API Reference