Creating a WAF application is a challenging task. I was to create a WAF application, I found few pre-written opensource tools but implementing them are challenging as well. I will 100s of websites and it would be really hard to implement my custom WAF on each of them manually and one by one.
Just like Google Analytics provide a JavaScript code to websites for their analytics. Then used puts the JS in their website.
I am looking for something similar. I want to create a WAF which any back-end and provide a JS code to my clients and they will put the JS on their website and WAF will start working there. It's gonna be really difficult so I am looking for a pre-built opensource tool if any is available.