Email to Fax — Send a Fax by Sending an Email
Send FAX Mail can turn an outgoing email into a fax. You attach your document to a normal email, address it to a special alias that encodes the destination fax number, and our inbound-email handler validates the sender and runs the same send pipeline the dashboard uses. There is no plugin to install in your mail client — it works in any app that can send email with an attachment. The one requirement is on the operator side: email-to-fax only runs when the operator has configured an inbound-email domain and secret, so confirm it is enabled on your deployment before relying on it.
Plan requirement
Email-to-fax runs on paid plans and enforces the same page quota and HIPAA rules as any other send. It is not part of the free trial's send-only shared number in the same way — it depends on the operator having configured the inbound-email domain (INBOUND_FAX_DOMAIN) and webhook secret; when those are unset the whole feature no-ops.
How it works
Your mail provider forwards each message to a webhook the operator wired up, and that POST is secret-gated so only your configured provider can trigger a send. The alias you send to encodes the recipient fax number, and the address is tied to a per-user secret so a stranger cannot fax on your behalf. Before anything is dialed, the pure sender-auth logic checks that the alias is real, that the message passed DMARC, and that the From address is on your allowed-senders list; a message that fails any of those is dropped silently rather than bounced, so an attacker gets no feedback. Valid mail then runs through the same gated pipeline as compose, so BAA, quota, and number rules all apply, and the attachment is normalized to a fax-ready PDF.
What you can do
- ✓Send a fax by emailing an attachment to an alias that encodes the destination number
- ✓Work from any email client — desktop, webmail, or phone — with no plugin
- ✓Restrict who can send by maintaining an allowed-senders list per account
- ✓Rely on DMARC + a per-user secret alias so unknown senders are silently dropped
- ✓Run the same BAA, quota, and number gates as a dashboard send
- ✓Manage your alias and allowed senders at /dashboard/settings
Setup steps
- 1Confirm the operator has configured the inbound-email domain and secret, or the feature is off
- 2Open /dashboard/settings and note your inbound alias and add each address you will send from to allowed senders
- 3Compose an email to <alias>.<number>@ the configured inbound domain
- 4Attach the document you want faxed as a PDF, image, or supported Office file
- 5Send the email from an address on your allowed-senders list that passes DMARC
- 6Watch the fax appear in /dashboard/history, where quota and status are tracked like any send
Example
To: you-secret-alias.15551234567@fax.yourdomain.com
From: billing@yourcompany.com (on your allowed-senders list)
Subject: Invoice 4021
Attachment: invoice-4021.pdfEmail to Fax — FAQ
No. Email-to-fax is not a plugin or an add-in; it works in any client that can send an email with an attachment, because the conversion happens on our side after your mail provider forwards the message. You address the message to the alias and attach the document — that is the whole client-side step.
Three checks run before any dial. The alias carries a per-user secret so it is not guessable, the message must pass DMARC, and the From address must be on your allowed-senders list. A message that fails any check is dropped without a bounce, so a would-be spoofer gets no confirmation that the alias even exists.
It depends on operator configuration. The feature only runs when the deployment has set the inbound-email domain and the webhook secret; with either unset the whole path no-ops. If sending to your alias does nothing, confirm with your operator that email-to-fax is turned on before troubleshooting your mail client.
Yes. A valid email runs the same gated send pipeline as the compose form, so the pages count toward your monthly allowance and the BAA and provisioned-number gates apply. Reaching your plan's monthly page limit blocks further emailed sends with an upgrade prompt, exactly as it would in the dashboard.
Build with the Email to Fax
API access and webhooks are included on the Business and Enterprise plans. Create a key at /dashboard/developers and start sending.
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