What is EFX? What Opens a EFX? File Format List from WhatIs.com

File Extension

EFX File Format

Fax document (Efax Reader)

EFX is a file extension for a document file used with eFax messenger software. EFX stands for EFaX. EFX files contain a fax document that can be sent and received by email, desktop application, and a web interface. 

EFX files can be opened by eFax messenger software. EFX files can also be sent if using the paid version of eFax messenger software.


MIME type: image/efax


Learn more about .EFX files:

Visit eFax web page.

Read more about Faxing at ITKnowledgeExchange.com.

This was last updated in September 2010
Editorial Director Margaret Rouse

Ask a Question About EFXPowered by ITKnowledgeExchange.com

Get answers from your peers on your most technical challenges

Tech TalkComment

What made you want to look up EFX Fax document (Efax Reader)? Please tell us where you read or heard it (including the quote, if possible).



    Contribute to the conversation

    All fields are required. Comments will appear at the bottom of the article.