usesend-mcp 0.1.0

FastMCP stdio server exposing the useSend email platform over MCP.

usesend-mcp

An MCP server for the useSend email platform (an open-source Resend/Postmark alternative). It gives any MCP client — Claude, Cursor, VS Code, Windsurf, Codex — 33 tools for transactional email, contacts, campaigns, domains, and analytics, over stdio.

Setup

1. Get a useSend API key (us_…) from Settings → API Keys at app.usesend.com (or your self-hosted instance).

2. Add the server to your MCP client. Almost every client uses the same JSON — paste this in and swap in your key:

{
  "mcpServers": {
    "usesend": {
      "command": "uvx",
      "args": ["usesend-mcp"],
      "env": { "USESEND_API_KEY": "us_your_api_key_here" }
    }
  }
}

uvx (from uv) downloads and runs the server from PyPI on demand — nothing to install first.

Where does that JSON go?

Client	Config file
Claude Code	.mcp.json (project root)
Claude Desktop	claude_desktop_config.json
Cursor	.cursor/mcp.json (project) or ~/.cursor/mcp.json
VS Code (Cline)	cline_mcp_settings.json
Windsurf	~/.codeium/windsurf/mcp_config.json

Prefer the command line?

claude mcp add usesend --env USESEND_API_KEY=us_your_api_key_here -- uvx usesend-mcp   # Claude Code
codex  mcp add usesend --env USESEND_API_KEY=us_your_api_key_here -- uvx usesend-mcp   # Codex CLI

Done — ask your assistant "list my useSend contact books" or "send a welcome email to [e-mail]" to check it works.

Run with Docker instead of uvx

Use the published image in any JSON config above:

{
  "mcpServers": {
    "usesend": {
      "command": "docker",
      "args": ["run", "-i", "--rm", "-e", "USESEND_API_KEY", "gardenbaum/usesend-mcp"],
      "env": { "USESEND_API_KEY": "us_your_api_key_here" }
    }
  }
}

Or run it directly (-i keeps stdin open for the stdio protocol, --rm cleans up on exit):

docker run -i --rm -e USESEND_API_KEY=us_your_api_key_here gardenbaum/usesend-mcp

Images: gardenbaum/usesend-mcp on Docker Hub, mirrored to ghcr.io/gardenbaum/usesend-mcp — linux/amd64 + linux/arm64.

Configuration

Environment variables (prefix USESEND_, also read from a .env file):

Variable	Default	Description
USESEND_API_KEY	(required)	API key, format us_….
USESEND_BASE_URL	https://app.usesend.com	API base URL; change for a self-hosted instance.
USESEND_DEFAULT_FROM	(unset)	Default sender for send_email / batch_send_emails.
USESEND_LOG_LEVEL	INFO	Log verbosity (DEBUG … CRITICAL).
USESEND_TIMEOUT	30	HTTP request timeout, in seconds.

Tools

33 tools across 6 domains. Every tool also accepts an optional response_format ("markdown" default, or "json" for machine-readable output).

Full tool list

Emails (6)

Tool	Description
usesend_send_email	Send a single transactional email (falls back to USESEND_DEFAULT_FROM if from_address is omitted).
usesend_batch_send_emails	Send up to 100 emails in a single request.
usesend_list_emails	List emails with pagination; optional start_date/end_date (ISO-8601) and domain_id filters.
usesend_get_email	Get details for a specific email.
usesend_cancel_email	Cancel a scheduled email.
usesend_update_email_schedule	Reschedule a scheduled email.

Contact Books (5)

Tool	Description
usesend_list_contact_books	List all contact books accessible by the API key.
usesend_get_contact_book	Get details for a specific contact book.
usesend_create_contact_book	Create a contact book, optionally with double opt-in.
usesend_update_contact_book	Update a contact book's name or double opt-in setting.
usesend_delete_contact_book	Delete a contact book.

Contacts (8)

Tool	Description
usesend_list_contacts	List contacts in a contact book, with pagination.
usesend_get_contact	Get details for a specific contact.
usesend_create_contact	Create a contact in a contact book.
usesend_update_contact	Update a contact's mutable fields.
usesend_upsert_contact	Create or update a contact by email address.
usesend_delete_contact	Delete a contact from a contact book.
usesend_bulk_create_contacts	Create multiple contacts in a single request.
usesend_bulk_delete_contacts	Delete multiple contacts in a single request.

Campaigns (7)

Tool	Description
usesend_create_campaign	Create an email campaign.
usesend_get_campaign	Get details for a specific campaign.
usesend_list_campaigns	List campaigns; optional status and search filters.
usesend_delete_campaign	Delete a campaign.
usesend_pause_campaign	Pause a running campaign.
usesend_resume_campaign	Resume a paused campaign.
usesend_schedule_campaign	Schedule a campaign for a future time.

Domains (5)

Tool	Description
usesend_list_domains	List all domains.
usesend_get_domain	Get details for a specific domain.
usesend_create_domain	Create a domain (name and region required).
usesend_verify_domain	Trigger DNS verification for a domain.
usesend_delete_domain	Delete a domain.

Analytics (2)

Tool	Description
usesend_email_time_series	Email volume time series (days: "7" or "30"); optional domain_id.
usesend_reputation_metrics	Sending reputation metrics (bounce/complaint rates); optional domain_id.

Development

uv sync --dev      # install runtime + dev dependencies
just check         # lint, format, types, import contracts, tests @ 100% diff coverage

Work happens on dev; main is the release branch (push a v* tag to publish). Architectural decisions are recorded as ADRs in docs/adr/. Logs go to stderr — stdout is reserved for the MCP protocol.

Contributing · Security · License

Contributions welcome — see CONTRIBUTING.md and the Code of Conduct. Report vulnerabilities privately via SECURITY.md, not public issues. Licensed under MIT © gardenbaum.