My website is on php and I want to integrate a good captcha in my website.
The traffic of the website is very high so most of the free available captcha either have issues on my server or they just fail and annoy my users.
Please let me know a good captcha software written in php which can handle very huge amount of traffic.
I'd recommend ReCaptcha. It's a very widely used external captcha service.
- Free
- Strong security
- Accessible to blind users
- 30+ million served daily
- Hosted by Google (you don't host the images nor script that generates them)
- Helps digitization of text
If you want to avoid image-based CAPTCHA systems, you can always use math questions:
Keep a table of questions/responses and validate their response with the correct one. Works well, and fast.