Actually, Zapier DOES accept files. In fact, I am trying to replace a Gravity Forms form with a CF7 form. The form uses Zapier to store a file on DropBox. The Zapier "Upload File" action requires "Must be a file object from another service (or some URL)" and Gravity Forms links to it without a problem. I guess the difference is that Gravity Forms saves the files while CF7 does not. However, I assume you link in before CF7 deletes the file and could either
1. Inhibit the delete, so that the file remains in the /wp-content/uploads/wpcf7_uploads/ directory, or
2. Copy it to a separate directory (like wp-content/uploads/cf7-connector/) and pass the URL to Zapier, or
3. Pay me a little bit to integrate file uploads to Zapier into your plugin.
Please let me know what you decide to do. I paid you for the Pro version specifically so I could get rid of Gravity Forms, given that your documentation says, for example, "Zapier provides integration with 600+ services. For example it is possible to send form data to Zapier and then use "Contact Form 7" submission to add subscribers to AWeber, ActiveCampaign, Constant Content, Drip, InfusionSoft or save them to Google Sheets and etc." without saying that you do not support file entries.
Alan Sikes
awsikes@interpreterfoundation.org