This is the first article in a two-part series where we show how to build your own anti-bot system to protect a login endpoint, without relying on third-party services. Why write this? Many bot detection solutions, reCAPTCHA, Turnstile, or vendor-maintained scripts, are designed for easy integration but come with tradeoffs.| The Castle blog
In every HTTP request, the user agent header acts as a self-declared identity card for the client—typically a browser—sharing information about the software and platform supposedly making the request. It usually includes details like the browser name and version, operating system, and rendering engine. But crucially, this identity| The Castle blog
Bots are often used to conduct attacks at scale. They can be used to automatically test stolen credit cards, steal user accounts (account takeover), and create thousands of fake accounts. Detecting bot activity has traditionally relied on techniques like Web Application Firewalls (WAFs), CAPTCHAs, and static fingerprinting. However, with the| The Castle blog
The good old days where bots used PhantomJS and could be detected because they didn’t support basic JavaScript features are over. It’s 2025, and the bots have never been as sophisticated as today. They leverage anti-detect automation frameworks, residential proxies and CAPTCHA farms. Even basic bots that leverage| The Castle blog
