Knowledge Base - FlexFax: Sending faxes through Email-to-Fax

Sending faxes by email has never been easier!

FlexFax allows you to send and receive multiple faxes at the same time through email anywhere in the world! View service options here.

FlexFax makes it easier than ever to send complex faxes with ease. No more waiting at the fax machine, or long delays while the fax ahead of yours finishes.

FlexFax uses a large pool of sending and receiving systems to ensure your fax is sent or received quickly with little chance of a busy signal (at least on our end of the connection!).

Even the Caller Name you send with (what the recipient sees as Call Display) can be customized per sending user.

FlexFax uses email and email attachments to send and receive faxes. Emails you send are converted and faxed - and you get confirmations every step of the way!

Faxes received are converted to a PDF document and emailed to you. Journals (logs) are available to review the previous days work. Received faxes can be re-emailed if they are lost or you accidentally delete them (for up to 45 days).


Step 1: Getting Started

To send your first fax (after your account is set up), you need to create a new email message, or forward one you received when you scanned a document to yourself.

The fax itself is comprised of your attachment(s). Often these can be PDF from a scanner for example.

Many attachment formats are supported and you can use the email body as a cover page! Check out the complete reference for more information.

The Subject line of the email is where you set the destination and options.

The format is: DESTINATION@SENDER followed by any options you need.

For example, if you wanted to send to +1 555 555 1234 and your number is +1 555 555 6789 you would specify a subject like:


If you wanted to add your email body as a cover page, just add the applicable option (C or L explained below):


Attach the document(s) that you want to send to your email. If there is one in a message you are forwarding, that will work too.

Send the message to the address you were given when your account was set up.

You can NOT bcc the fax server - it may be "to or "cc" only.

Now that you have sent your first fax - how do you know it worked? Read on for details on confirmation!


Step 2: Confirmation / What happens next?

When FlexFax receives your email, first it checks to ensure you are authorized to send faxes from the fax number you provided in your Subject. If you are not, the message is not processed, but a notice is forwarded to support to help us help you when you add or change staff.

Presuming you are authorized; the system checks if you need a cover page. If you include an email body but did not specify a cover page option (C or L), we ignore it. That allows you to make notes on the faxes you send in the message body. If on the other hand you included an option to prepare a cover page, we make it happen. Plain text and HTML (with images) are both supported - but keep in mind that fax is only black and white.

Next, we check your attachments, and process every one we can. If we detect an attachment, we can not process, we will warn you and the recipient that the attachment was not included. That way you both know something is missing / was not sent.

Once each attachment is converted, we count the pages and prepare your confirmation email.

We check two thresholds prior to sending: 

Maximum Page Count. To prevent mistakes (attachment of overly large documents or too many documents to make a practical fax), if your page count exceeds the maximum pages for your account, we return an error message / failure to queue so you can correct the issue or contact Client Support about it.

Maximum Faxes Per Hour. To prevent accidents, abuse of your account, or accidental problems from mail loops (when a mail server delivers a message repeatedly), we check to see how many faxes your account has sent in the last hour. If you have exceeded the maximum faxes per hour, we return an error message / failure to queue.

If there are no errors, we return a Confirmation / Fax Queued message. This message lists the pages and attachments you sent, and also give you a link which you can use to cancel the job if you realize you made a mistake.


Step 3: Requeuing (if needed)

In the event we are not immediately successful sending your fax, we will send you a Requeuing message - just to let you know that we will wait a few minutes and then try again.

Remember that the receiving party might still be using a single phone line and it may be busy.

Faxes will be tried 3 times before we give up. If at any time you realize you have made a mistake, you can cancel the fax.


Step 4: Success or Failure

Whether we succeed or fail, we will send a final message indicating whether the fax was sent or not. We also log the activity and will add that to your journal if you have that option enabled.

If your fax does fail 3 times, please check the number you are sending to and read the failure messages. A bad attachment or other problem may be explained. If you want to retry, simply find the sent message in your sent items, open it and resend it. In outlook this is done by clicking Actions -> Resend this Message...

Applies To


Related Articles

FlexFax: Fax-To-Email Fax Detection

FlexFax: Fax-To-Email Receive Journal

FlexFax: User Manual - Sending By Email (Complete Reference)