Captcha4 focuses on an API-first approach, which means that the customer gets a documented API provided in our first release.

Depending on the customer's needs, the customer can implement the text-based captcha challenge mechanism on his backend side. This gives customers the ability to respond individually to specific events and integrate the captcha mechanism into their own process.

The following graphic illustrates a typical Captcha4 flow.

This illustration shows how the captcha4 for a text-based captcha in general works.

1. Your server request with your API key a new challenge for the client.
2. You receive from the Captcha4 API a new generated text-based captcha challenge.
3. Your server forwards the received challenge to the client. You can also add more context to the client response if needed.
4. The client receives the challenge image and fetches the image from the Captcha4 server.
5. After the client receives the image, he can send the response to your server.
6. Your server receives the challenge-response and uses the Captcha4 endpoint to verify the client's answer.
7. You will receive a result about the submitted answer, whether the check was successful or not.

The initial interactions with the client and the subsequent response to the client after the challenge has been reviewed will vary depending on your needs.

Captcha4 takes care of the challenge creation and verification. All you have to do is integrate the text-based Captcha4 service into your flow.