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Resend MCP Server
An MCP server for Resend — connect any MCP-compatible client to the Resend transactional email API.
What is this?
An MCP (Model Context Protocol) server that gives AI assistants and agents full access to Resend's email API — send single or batch emails, manage sending domains, API keys, audiences, and contacts — through natural language.
Use it with Claude Desktop, Cursor, Windsurf, Cline, Continue, or any MCP-compatible client to send emails, manage infrastructure, and build automation around email.
Why use this?
- 18 built-in tools — covers sending (single + batch), domains, API keys, audiences, and contacts
- Send emails by talking — "send a welcome email to [email protected]" just works
- Manage your infrastructure — create/verify/delete domains, mint/revoke API keys, manage contacts
- Batch sending — send up to 100 emails in a single API call
- Full contact CRUD — create, read, update, and delete contacts across audiences
- Rate-limited automatically — respects Resend's 10 req/s free tier, retries on 429
- Works with every MCP client — Claude Desktop, Cursor, Windsurf, Cline, Continue, and more
Quick Start
Add to your MCP client config (e.g. claude_desktop_config.json):
{
"mcpServers": {
"resend": {
"command": "npx",
"args": ["-y", "resend-mcp-server"],
"env": {
"RESEND_API_KEY": "re_xxxxxxxxxxxx"
}
}
}
}Get a free API key at resend.com/api-keys.
Use it
Ask your AI assistant things like:
- "Send an email to [email protected] thanking her for signing up"
- "List the last 5 emails I sent"
- "What happened to email ID
abc-123?" - "Create a new sending domain for
mail.acme.com" - "Verify domain
domain-xyz" - "Mint a new API key called 'production-server'"
- "Add [email protected] to audience
audience-1"
Tools
| Tool | Description |
|---|---|
send_email | Send a transactional email (HTML or plain text, with Cc/Bcc/Reply-To) |
send_batch_email | Send up to 100 emails in a single API call |
list_emails | List recent sent emails with their delivery status |
get_email | Get details for a specific email by ID |
create_domain | Add a new sending domain |
list_domains | List all sending domains in your account |
verify_domain | Trigger DNS verification for a domain |
delete_domain | Remove a sending domain |
create_api_key | Create a new API key (full, sending, or domain-scoped) |
list_api_keys | List all API keys (tokens are hidden) |
delete_api_key | Delete an API key by ID |
list_audiences | List all audiences in your account |
create_audience | Create a new audience for organizing contacts |
list_contacts | List contacts in an audience |
get_contact | Get details for a specific contact by ID |
create_contact | Add a new contact to an audience |
update_contact | Update a contact's email, name, or subscription status |
delete_contact | Remove a contact from an audience |
Use Cases
Transactional Email Automation
"Send a welcome email to every new signup" — automate onboarding flows, receipts, and notifications through natural language. No more switching between email dashboards.
Domain Management
"Add mail.acme.com as a sending domain and verify it" — manage DNS records, DKIM, and SPF through your AI assistant instead of logging into Resend's dashboard.
Contact & Audience Management
"Add [email protected] to my VIP audience" — build and segment contact lists without touching a spreadsheet. Full CRUD on contacts and audiences.
Batch Campaigns
"Send this newsletter to all contacts in audience-1" — batch-send up to 100 emails in one call. Perfect for newsletters, product announcements, or re-engagement campaigns.
Infrastructure Audit
"List all my API keys and domains" — audit your Resend setup in seconds. See which keys are active, which domains are verified, and clean up stale resources.
Security
- API key required — Resend API key is passed via environment variable, never logged or stored in files.
- No local file access — does not read or write any files on your machine.
- No shell access — does not execute commands or spawn processes.
- Rate-limited — automatically caps requests at ~9 req/s to stay within Resend's free tier.
- Open source — MIT licensed. Inspect the code at GitHub.
Troubleshooting
Rate limit errors (429)
The server auto-retries on 429 with a 2s backoff. Free tier allows 10 req/s. The server caps at ~9 req/s to stay safe. If you hit this frequently, consider upgrading your Resend plan.
"Invalid API key" errors
Verify your RESEND_API_KEY starts with re_ and is active at resend.com/api-keys. Keys take up to 30 seconds to propagate after creation.
Server won't start
Make sure Node.js 18+ is installed: node --version. If using npx, ensure npm is up to date: npm install -g npm@latest.
MCP client can't connect
Verify the config path is correct. Claude Desktop uses ~/Library/Application Support/Claude/claude_desktop_config.json on macOS and %APPDATA%\Claude\claude_desktop_config.json on Windows. Restart the client after config changes.
Emails not delivering
Check list_emails for delivery status. Common issues: missing DNS records (run verify_domain), bounce due to invalid address, or domain not yet verified. Resend's dashboard shows detailed webhook events.
Requirements
- Node.js 18+
- A Resend account and API key (
RESEND_API_KEY)
Rate Limits
The server automatically rate-limits requests to ~9 calls/second to stay safely under Resend's free-tier limit of 10 req/s. If you hit a 429 anyway, it waits 2s and retries once.
Development
git clone https://github.com/friendlygeorge/resend-mcp-server.git
cd resend-mcp-server
npm install
npm run build
RESEND_API_KEY=re_xxxx npm startLicense
MIT