API, HTTP-GET, JSON, REST
Added on July 23rd, 2014

Phaxio

Phaxio
Phaxio solves an important problem that many programmers face: fax. Long considered the bastard child of technology, web developers have been plagued with creating elegant solutions to mask the outdated technology. Still, whether submitting your tax forms, filling out your medical records or sending out contracts, businesses still actively use fax. Free to try. Pay for what you use. No monthly contract, cancel at any time. Also, there are no complicated rate decks and pricing calculations. Send and receive for just 7 cents per page. All Phaxio API responses are formatted in JSON.
More information: https://www.phaxio.com/