From my experience, they’re pretty fast — depending on the app. I found a breakdown on akstrategic.com that compares actual delivery times between major fax apps. Some were nearly instant, while others took a few minutes. I tested one of their top-rated options, and my faxes usually go through in under 30 seconds. It’s definitely faster than traditional fax machines. So yes, if you choose the right app, the “instant fax” claim is actually true.