Hacker101 offers a free web security class with lessons and Capture the Flag challenges.
CTF101
The CTF101 wiki introduces Capture the Flag competitions and explains related security concepts.
About CTF101
The CTF101 wiki introduces Capture the Flag competitions and explains related security concepts.
CTF101 is a website in our Learn to Code collection, part of the Education & Learning directory. It runs in your web browser, so there's nothing to install.
Not quite what you need? Close alternatives include Hackers101, CTFtime, and CTF Sites — compare them below.
CTF101 at a glance
- Website
- ctf101.org
- Category
- Education & Learning › Learn to Code
- Type
- Website
- Pricing
- Not confirmed. Check the site
- Platforms
- Web
- Open source
- Not stated
- Language
- English
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
CTF101 alternatives
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CTF Sites lists Capture the Flag sites and provides a directory for finding cybersecurity challenges.
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CTF101 FAQ
What is CTF101?
The CTF101 wiki introduces Capture the Flag competitions and explains related security concepts.
Can I use CTF101 in my browser?
Yes. CTF101 works on the web, so you can use it from any modern browser without installing anything.
Is CTF101 working?
ctf101.org responded when checked on Oct 5, 2026. Its current availability has not been confirmed.
What are the best alternatives to CTF101?
Popular alternatives to CTF101 include Hackers101, CTFtime, CTF Sites, and PHP Tutorial. We list 8+ options matched by topic, tags and features.
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