MCP Server – Send & manage emails, contacts and sending domains

Sidemail MCP server enables you to programmatically send and manage transactional emails, contacts, sending domains, templates, inbound emails, project settings, API logs, and Messenger features – right from MCP agent mode in VS Code, Claude, Cursor, and other MCP clients.

MCP server features

• Manage sending domains
• Review and update project settings
• Test sending transactional emails
• Manage contacts and groups
• Create, update, and delete Messenger drafts
• Create, update, and query templates
• Manage inbound routes and inspect received emails
• Query sent emails, contacts, templates, API request logs, and log stats
• Validate email addresses, with optional deep SMTP validation

Prerequisites

• Sidemail API Key
• Node.js v20 or newer, only for the local NPM package setup

Hosted HTTP setup

Use the hosted Streamable HTTP MCP server when your client supports remote MCP servers:

https://api.sidemail.io/mcp

Send your Sidemail API key in the Authorization header as a Bearer token.

{
	"servers": {
		"sidemail": {
			"type": "http",
			"url": "https://api.sidemail.io/mcp",
			"headers": {
				"Authorization": "Bearer ${input:sidemail-key}"
			}
		}
	},
	"inputs": [
		{
			"type": "promptString",
			"id": "sidemail-key",
			"description": "Sidemail API Key",
			"password": true
		}
	]
}

Local NPM setup

Use the local NPM package when your client expects a stdio MCP server.

Microsoft VS Code setup (assisted)

1. Open the Command Palette (Ctrl/Cmd + Shift + P).
2. Type “MCP: Add Server…” and select it.
3. Select "NPM Package".
4. Enter @sidemail/mcp and confirm it.
5. Confirm the installation.
6. Enter your Sidemail API key and confirm it.

Microsoft VS Code local setup (manual)

Alternatively, you can install it manually by modifying the mcp.json configuration file.

1. Open the Command Palette (Ctrl/Cmd + Shift + P).
2. Type “MCP: Open User Configuration” and select it.
3. Add the configuration below and save changes.

{
	"servers": {
		"sidemail-mcp": {
			"type": "stdio",
			"command": "npx",
			"args": ["-y", "@sidemail/mcp"],
			"env": {
				"SIDEMAIL_API_KEY": "${input:sidemail-key}"
			}
		}
	},
	"inputs": [
		{
			"type": "promptString",
			"id": "sidemail-key",
			"description": "Sidemail API Key",
			"password": true
		}
	]
}

Claude Desktop local setup

Edit (or create) the config file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

{
	"mcpServers": {
		"sidemail": {
			"command": "npx",
			"args": ["-y", "@sidemail/mcp"],
			"env": { "SIDEMAIL_API_KEY": "your-key" }
		}
	}
}

Cursor setup

Create or edit ~/.cursor/mcp.json:

{
	"mcpServers": {
		"sidemail": {
			"command": "npx",
			"args": ["-y", "@sidemail/mcp"],
			"env": { "SIDEMAIL_API_KEY": "your-key" }
		}
	}
}

CLI Usage

npx @sidemail/mcp

For local HTTP testing:

MCP_TRANSPORT=http npx @sidemail/mcp

MCP Server Tools

Domains

• list-domains: List all sending domains
• create-domain: Add a new sending domain
• check-domain: Check domain verification and DNS status
• setup-domain-mail-from: Set up custom Mail-From DNS records
• delete-domain: Remove a sending domain

Example – Adding a new sending domain:

Projects

• get-project: Get the current project
• create-linked-project: Create a linked project
• update-project: Update project settings and email design
• delete-linked-project: Delete the current linked project

Messenger

• list-messenger-drafts: List Messenger drafts
• get-messenger-draft: Get Messenger draft by ID
• create-messenger-draft: Create a Messenger draft
• update-messenger-draft: Update a Messenger draft
• delete-messenger-draft: Delete a Messenger draft

Example – Writing a product update email:

Groups

• list-groups: List all contact groups
• create-group: Create a new contact group
• update-group: Update a contact group
• delete-group: Delete a contact group

Contacts

• create-or-update-contact: Create or update a contact
• list-contacts: List contacts with pagination
• query-contacts: Query contacts with filters
• clean-contacts-batch: Validate and clean contacts in a group
• find-contact: Find a contact by email
• delete-contact: Delete a contact

Emails

• send-email: Send a transactional email
• query-emails: Query sent emails
• get-email: Retrieve an email by ID
• delete-email: Delete a scheduled email

Email validation

• validate-email: Validate an email address. Use isDeep: true for SMTP mailbox validation; deep checks can consume validation credits.

Templates

For template content element structure and examples, see the Templates API content nodes documentation. Agents can also inspect list-template-gallery or get-template output before creating complex template updates.

• list-templates: List email templates
• get-template: Retrieve a template by ID
• create-template: Create an email template
• update-template: Update an email template
• list-template-gallery: List gallery templates
• list-template-fonts: List supported template fonts

Inbound emails

• list-inbound-routes: List inbound routes
• create-inbound-route: Create an inbound route
• update-inbound-route: Update an inbound route
• delete-inbound-route: Delete an inbound route
• list-received-emails: List received inbound emails
• get-received-email: Retrieve a received inbound email by ID

API logs

• query-api-request-logs: Query recent API request logs
• get-api-request-log-stats: Get API request log statistics

More resources

• Github repository: sidemail/sidemail-mcp-server
• NPM package: @sidemail/mcp
• Features overview