SendThisFax

Send real faxes to EU institutions: pay per fax via checkout link or prepaid API key.

CommunityOnlineAPI key requiredGlobalFreeCan modify data

What it can do

    What data it sees

    Do you need an account

    An API key from the service settings is required

    Send real faxes to EU institutions: pay per fax via checkout link or prepaid API key.

    How to connect

    How to connect SendThisFax to Claude

    The server address to paste into Claude settings:

    https://www.sendthisfax.com/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect SendThisFax to ChatGPT

    The server address to paste into ChatGPT settings:

    https://www.sendthisfax.com/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect SendThisFax to Cursor

    The server address to paste into Cursor settings:

    https://www.sendthisfax.com/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (4)

    Raw names from tools/list. Only developers need these.

    get_priceGet the price quote in euro cents for sending a fax. Pricing: 5.00 EUR for up to 5 pages, plus 0.50 EUR per extra page, plus VAT based on the payer's billing country (0% VAT outside the EU).
    send_faxSubmit an uploaded PDF for faxing. Step 1 (before this tool): upload the PDF over plain HTTP multipart, using any HTTP client you have — shell, JavaScript fetch with FormData, Python, etc.: curl -F "file=@document.pdf" https://www.sendthisfax.com/api/upload fetch("https://www.sendthisfax.com/api/upload", {method: "POST", body: formDataWithFile}) The response contains fax_public_id and page_count. PDFs must be unencrypted, at most 50 MB and 1000 pages. Step 2: call this tool with the fax_public_id and the recipient fax number. Two modes: - With an API key (Authorization: Bearer stf_live_... on this MCP connection): the fax price is debited from the prepaid credit balance and sending starts immediately — no checkout, no browser. sender_email and billing_country are optional (they default to the key's records). Buy credits at https://www.sendthisfax.com/en/credits. - Without an API key: sender_email and billing_country are REQUIRED and the tool returns a checkout_url the USER must pay in a browser; the fax is sent automatically once paid. In both modes, poll get_fax_status until status reaches "delivered" or "failed" (failures after payment are auto-refunded). For integration testing, +19898989898 is the designated test recipient number.
    get_fax_statusGet the current status of a fax. Poll this after send_fax until a terminal state. Fax lifecycle: draft (uploaded, not submitted) -> pending (submitted, awaiting payment) -> sending -> delivered | failed. Payment lifecycle: unpaid -> verifying/open (checkout in progress) -> paid | failed | canceled | expired. A fax that fails after payment is refunded automatically to the payer.
    check_balanceGet the prepaid credit balance of the API key used to authenticate this MCP connection. Requires a bearer API key (stf_live_...). Buy or top up credits at https://www.sendthisfax.com/en/credits — credits never expire and failed faxes are re-credited automatically.