I've used interfax.net for years - to send faxes, I don't receive them. I wouldn't be surprised if you can receive faxes too, though. It's always been a great

I've used interfax.net for years - to send faxes, I don't receive them. I wouldn't be surprised if you can receive faxes too, though. It's always been a great service, and no ongoing fees - I just pay a few cents every time I send a fax. Pretty old-school site, but it has a SOAP API that works. Hope that helps.