Using captchas are currently free of usage. The API module is quite simple built: Requesting a captcha from https://api.tornevall.net/2.0/captcha/ will return a hash and an image url. You can also call for the captcha with /captcha/getCaptcha.
The getCaptchaResponse looks like this:
By running /captcha/getCaptcha, your response will instead be something like below:
|Response Parameter Key||Response Parameter Value|
|imageUrl||The url of where you can find the captcha image|
|imageHash||The hash string that you use for matching the captcha string|
Example of a captcha rendered by the captchaApi:
Testing this string against the captchaApi is being made either through (example): https://api.tornevall.net/2.0/captcha/testcaptcha/hash/<imageHash>/response/q23lqctg or https://api.tornevall.net/2.0/captcha/testcaptcha and the rest as POST-content or JSON.
In this case, the response of this query will be:
If the control instead fails, the response will throw back an exception with error code 2003: TAPI_PLUGIN_CAPTCHA_STRING_MISMATCH
Each captcha expires after 5 minutes.