Sapo Captcha API

Sapo Captcha
SAPO is a Portuguese Internet service provider whose main web site acts as a web portal featuring a directory of Portuguese sites. SAPO Services provides a large suite of web services and applications to developers worldwide. The Sapo Captcha API lets developers generate and customize captchas. Customization options include font, colors, sound and image. It uses RESTful calls and responses are formatted in XML.