Frequently asked questions
Can Claude or ChatGPT send faxes?
Yes – with mcpfax. mcpfax is an MCP connector (Model Context Protocol) that you add in Claude (claude.ai, Desktop, Code) or ChatGPT. Your AI assistant can then send real faxes worldwide. You can also send faxes directly on the website.
Do I need a fax machine or a fax number?
No. All you need is an mcpfax account with some balance. The recipient gets a completely normal fax.
Can I receive faxes too?
No, mcpfax is for sending only.
How much does a fax cost?
To the EU, Switzerland, UK, USA, Canada and other countries: CHF 0.90 for the first page and CHF 0.18 for each additional page (incl. VAT). Double the rate to all other countries (CHF 1.80 / CHF 0.36). No subscription, no base fee.
What happens if a fax doesn’t arrive?
If the transmission finally fails (e.g. busy, no fax machine), the amount is automatically refunded to your balance and you receive an email.
Which file formats are supported?
PDF, Word (DOCX), text, Markdown, HTML, JPG and PNG. Claude can also pass text directly, which mcpfax turns into a PDF.
Will Claude send without my approval?
mcpfax instructs Claude to state the recipient, page count and price before every send and to wait for your confirmation. In addition, Claude usually asks for approval itself before paid actions.
How long are my documents stored?
Fax documents are deleted automatically after 30 days. Date, recipient, page count and status are kept for your accounting.
Why is there a daily limit?
To prevent abuse: on the first day you can send 50 faxes, after that the limit doubles every day. If you need more, just get in touch.
Can I send advertising faxes?
No. Unsolicited advertising by fax is prohibited in Austria, Germany and the EU. Accounts that violate this will be blocked.
Do I get an invoice?
Yes, every purchase automatically comes with an invoice by email showing VAT or a reverse charge note.
Does mcpfax work with ChatGPT too?
Yes. mcpfax uses the open Model Context Protocol and can be added to ChatGPT as an app/connector with the same URL.
Can I also fax by email?
Yes. Enable “Email-to-fax” in your account and send an email to faxnumber@fax.mcpfax.de, e.g. 004930123456@fax.mcpfax.de, with the document attached. Only allowed senders can fax; optionally with a PIN and confirmation link.
What happens if the line is busy?
mcpfax automatically tries two more times, about 10 minutes apart. You only pay once; if the transmission ultimately fails, the full amount is credited back. You can download the transmission report as a PDF at any time.
Which countries can I fax to?
mcpfax sends faxes to more than 200 countries. The overview “Fax by country” lists every country with its price per page and instructions for Claude, ChatGPT, email and browser. All countries and prices →