resend-email

Send emails using Resend API. Use when the user needs to send emails without configuring SMTP servers. Supports text and HTML emails, multiple recipients, CC/BCC, and bulk sending. Ideal for notifications, alerts, newsletters, and automated email workflows.

3,891 stars

Best use case

resend-email is best used when you need a repeatable AI agent workflow instead of a one-off prompt.

Send emails using Resend API. Use when the user needs to send emails without configuring SMTP servers. Supports text and HTML emails, multiple recipients, CC/BCC, and bulk sending. Ideal for notifications, alerts, newsletters, and automated email workflows.

Teams using resend-email should expect a more consistent output, faster repeated execution, less prompt rewriting.

When to use this skill

  • You want a reusable workflow that can be run more than once with consistent structure.

When not to use this skill

  • You only need a quick one-off answer and do not need a reusable workflow.
  • You cannot install or maintain the underlying files, dependencies, or repository context.

Installation

Claude Code / Cursor / Codex

$curl -o ~/.claude/skills/resend-email-sender/SKILL.md --create-dirs "https://raw.githubusercontent.com/openclaw/skills/main/skills/aprilvkuo/resend-email-sender/SKILL.md"

Manual Installation

  1. Download SKILL.md from GitHub
  2. Place it in .claude/skills/resend-email-sender/SKILL.md inside your project
  3. Restart your AI agent — it will auto-discover the skill

How resend-email Compares

Feature / Agentresend-emailStandard Approach
Platform SupportNot specifiedLimited / Varies
Context Awareness High Baseline
Installation ComplexityUnknownN/A

Frequently Asked Questions

What does this skill do?

Send emails using Resend API. Use when the user needs to send emails without configuring SMTP servers. Supports text and HTML emails, multiple recipients, CC/BCC, and bulk sending. Ideal for notifications, alerts, newsletters, and automated email workflows.

Where can I find the source code?

You can find the source code on GitHub using the link provided at the top of the page.

Related Guides

SKILL.md Source

# Resend Email Sender

Send emails via Resend API - no SMTP configuration needed.

## Quick Start

### 1. Configure

Set environment variables in `.env`:

```bash
RESEND_API_KEY=your_resend_api_key
RESEND_FROM=onboarding@resend.dev  # Optional, defaults to Resend test domain
```

Get API key at https://resend.com

### 2. Send Email

```bash
openclaw run resend-email \
  --to="recipient@example.com" \
  --subject="Hello" \
  --text="Plain text message"
```

## Usage

### Basic Text Email

```bash
openclaw run resend-email \
  --to="user@example.com" \
  --subject="Notification" \
  --text="Your task is complete."
```

### HTML Email

```bash
openclaw run resend-email \
  --to="user@example.com" \
  --subject="Welcome" \
  --html="<h1>Welcome!</h1><p>Thanks for joining.</p>"
```

### Multiple Recipients

```bash
openclaw run resend-email \
  --to="user1@example.com,user2@example.com,user3@example.com" \
  --subject="Team Update" \
  --text="Meeting at 3 PM."
```

### CC and BCC

```bash
openclaw run resend-email \
  --to="primary@example.com" \
  --cc="manager@example.com" \
  --bcc="archive@example.com" \
  --subject="Report" \
  --text="Please find the attached report."
```

### From Agent

When agent needs to send email:

```bash
# Use exec to call the skill
exec openclaw run resend-email \
  --to="recipient@example.com" \
  --subject="Automated Notification" \
  --text="This email was sent automatically by the agent."
```

## Configuration Options

| Variable | Required | Default | Description |
|----------|----------|---------|-------------|
| `RESEND_API_KEY` | Yes | - | Your Resend API key |
| `RESEND_FROM` | No | `onboarding@resend.dev` | Default sender address |

## Sender Addresses

- **Test domain**: `onboarding@resend.dev` (default, no setup required)
- **Custom domain**: `noreply@yourdomain.com` (requires domain verification in Resend dashboard)

## Limitations

- Attachments not supported (Resend API requires base64 encoding)
- Rate limits apply based on Resend plan
- Email size limits per Resend documentation

## Troubleshooting

**"RESEND_API_KEY not configured"**
- Set `RESEND_API_KEY` in `.env` file or environment

**"Failed to send email: Unauthorized"**
- Check API key is correct and active
- Verify API key has email sending permission

**"Failed to send email: Bad Request"**
- Check recipient email format is valid
- Verify `from` address is verified (for custom domains)

## Resources

- `scripts/send_email.py` - Main email sending script

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