---
title: "An MCP server for Onetime Fax"
description: "Connect an AI assistant to Onetime Fax to prepare a fax, review the price, send it with your approval, and check delivery."
canonical: "https://www.onetimefax.com/blog/onetime-fax-mcp-server/"
---

# An MCP server for Onetime Fax

Published:  Sun Oct 11 2026

You can now connect an AI assistant to Onetime Fax. Our MCP server is available at `https://app.onetimefax.com/mcp`.

MCP (Model Context Protocol) gives an assistant a standard way to use tools from another service. With your permission, an MCP client can prepare a fax in your Onetime Fax account, attach a document, show you the recipient and price, send after you approve those details, and check the delivery status.

## Your account, your choice of assistant

This is a connection you choose to make. Onetime Fax receives the fax details and documents your client sends to its tools; connecting does not give it access to the rest of your conversation. Your MCP client connects only after you sign in and approve its access.

The server uses the same account and prepaid credits as the [Onetime Fax developer API](/developers). Each person connects with their own verified developer account. Creating a draft and getting a quote do not spend credits. Sending a fax does.

## What you can ask it to do

For example, you can ask a connected assistant:

> “Prepare a fax to +1 415 555 1212 with this PDF. Show me the recipient, files, page count, and price before sending.”

The assistant can create the draft, attach your file, and retrieve a quote. You can then approve the exact recipient, attached files, and price. The send tool checks those details again before it charges your credits and queues the fax. Afterward, you can ask for its status.

The MCP tools also let you check your account balance and look up a fax you have already created. A client that supports file attachments can pass a document to the server. If it cannot, you can provide a publicly accessible HTTPS download link instead; do not use that option for a document you do not want exposed at a public URL. Each file must be 25 MB or smaller.

## Connect

1. [Create a developer account](https://app.onetimefax.com/developers/signup), or sign in to your existing one, and verify your email.
2. In a client that supports custom remote MCP servers and OAuth, add `https://app.onetimefax.com/mcp`. In ChatGPT or Grok, look for the custom MCP connection option if it is available to your account.
3. Sign in to Onetime Fax and review the access request. You can manage or revoke the connection in [developer connections](https://app.onetimefax.com/developers/connections).
4. Add credits in the [developer console](https://app.onetimefax.com/developers) before you send. The MCP tools cannot add credits, but an assistant with browser access can help you use the console to buy them.

Client menus and file attachment support vary. Check what your client will share with connected tools before sending sensitive documents. The MCP server is an optional way to use Onetime Fax; you can still send from the [website](/send) or use the [REST API](/developers).

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