Web service API
When you sign up for your own account, you are provided with a unique API key. This key allows you to access the XML web service interface.
A single CAPTCHA can be requested from the URL:
http://textcaptcha.com/api/your_api_key/
The XML response contains question and answer elements:
- The question element is the plain text of the logic question.
- The answer elements are the MD5 hashes of any permitted answers. All answers are converted to lowercase before being hashed, and this should be mirrored when you check a user response against these answers.
<captcha> <question>If tomorrow is Saturday, what day is today?</question> <answer>f6f7fec07f372b7bd5eb196bbca0f3f4</answer> <answer>dfc47c8ef18b4689b982979d05cf4cc6</answer> </captcha>
In the example XML, there are two permitted answers: "Friday" and "Fri". The MD5 hash of both (lower-case) answers are included. For an example of how to convert this XML into a form-based challenge, read how our service works.
How reliable is the service?
The service is provided from a European Amazon EC2 server which is monitored using the Wormly service. I don't provide an explicit SLA, but do my best to provide a completely reliable service.