FAX.PLUS

I would strongly recommend FaxZero instead if they meet your needs. They're a little less sophisticated, but in my experience they don't play games. I signed up for the basic plan, advertised at up to 60 pages per fax, so that I could send a long fax. I set it up, sent it, and a short time later got an email saying that they'd given up because the number was busy. So I set it up again, this time selecting the option to retry. Evidently, though, I was supposed to infer that that meant to retry at added cost if the fax failed midstream. They got through this time, transmitted thirty pages before getting cut off, and repeated the process two more times, charging me for 90 pages and still failing to transmit my entire fax. I contacted support about being billed for triple the number of pages actually transmitted, and their response was that I'm supposed to break up faxes into "5 to maximum 10 pages per file" in contradiction to their advertised 60. The next month, PayPal sent me notification that I'd been billed again. Within five minutes, I logged into FAX.Plus, cancelled my subscription, and messaged support to ask if they could please refund it because I don't want another month of service right now. Their response? Nope, no refunds. And, you know what? Fine, my mistake, they got me. But they won't be getting me ever again.

Advertises HIPAA compliance, but note that's only available with the "Advanced Security Controls" enabled which are only an option with their top-tier "Enterprise" plan (at $59.99 USD / month when billed monthly, as of October 2021).

Pros: Very professional, clean web user interface.

Cons: You can't add any amount of credit you want. You are restricted to adding fixed amounts of credit ($5.99, $11.99, etc.)