The Hacker101 CTF is a game designed to let you learn to hack in a safe, rewarding environment. Hacker101 is a free educational site for hackers, run by HackerOne. This CTF is another integral component in our plans to make the world a better place, one bug at a time.

What is a CTF?

CTF stands for Capture The Flag, a style of hacking event where you have one goal: hack in and find the flag. Flags are placed in various locations -- they might be in a file, in the database, stuck into source code, or otherwise -- and your goal is to hunt them all down. Each flag looks something like ^FLAG^37ae568362f974017fa575f08cd215044cd6bb395c3f5e5e293ee5324ba6769c$FLAG$, so you'll know the instant you see one.

Get Started!

Sign up now and then check out our guide on how to play or just jump right in.

Whether you're brand new or a seasoned hacker, you may also want to check out our companion site, Hacker101, where you can learn everything from absolute beginner to advanced hacking techniques.