I have built an app for this that works perfectly using the API - the only missing component is being able to drop in the serial/lot number for required items. Otherwise, it’s complete.
This is the receipt uploader. It has a failsafe backup of sending me uploads it’s not 95% sure of.
This is the Order Acknowledgement/Packing Slip/Vendor Bill (against PO or not) app - Eventually, I’ll make it so emails with attachments can be forwarded directly to the apps.