Ha0ker is the online identity of Gagandeep Singh, a professional ethical hacker and bug bounty hunter focused on web application security, especially IDOR, broken access control, and sensitive data exposure issues. He learns by hacking real systems through bug bounty and vulnerability disclosure programs, and his work has led to valid vulnerabilities, bounties, and Hall of Fame acknowledgments from multiple global companies. Some of his best work happens on invite‑only private programs on platforms like Bugcrowd and HackerOne, where only a small group of trusted, proven researchers are allowed to test more sensitive targets. Being selected for many of these private engagements shows that platforms and companies trust his skills, judgment, and professionalism. Under the handle Ha0ker, Gagandeep's goal is simple: use offensive security knowledge to find real bugs, protect real users, and make the internet safer.