Ryan Montgomery, Official Website - Discussions

Ryan Montgomery is an ethical hacker and cybersecurity expert known for two things: elite technical skill — he's ranked #1 on TryHackMe's Capture The Flag leaderboard — and a mission to use that skill against child predators online. He's the founder of Pentester, a cybersecurity platform based in Boca Raton, Florida, and serves as Chief Technology Officer of the Sentinel Foundation, where he works with law enforcement to combat child exploitation and human trafficking. With over 19 years in the field, he's become one of the most visible white-hat hackers in America. This is an independent profile — not affiliated with Montgomery or his organizations.

Quick facts

• Who: Ryan Montgomery — ethical hacker, penetration tester, cybersecurity educator.
• Known as: "0day" (his handle across X, Instagram, and YouTube).
• Credentials: #1 ranked on TryHackMe's CTF leaderboard; 19+ years in cybersecurity.
• Founder: Pentester (pentester.com) — vulnerability scanning, breach detection, and risk mitigation tools.
• Role: CTO of the Sentinel Foundation — tech-driven fight against child exploitation.
• Public profile: viral podcast appearances (notably Shawn Ryan Show #255), live hacking demos.

From hacker to hunter

Montgomery's origin story is unusually public. He's spoken openly about a difficult youth — addiction, recovery, time as a firefighter — before channeling his technical obsession into cybersecurity. The throughline of his career is a simple conviction: the same skills used to break into systems can be used to protect people. That philosophy took its sharpest form in his predator-exposure work: infiltrating dark-web forums and chatrooms where predators operate, gathering evidence, and working with law enforcement. He's demonstrated techniques live on podcasts — showing audiences in real time how exposed they are.

Our look at his predator-exposure work covers what those operations involve and why they've made him both celebrated and controversial.

Pentester and the Sentinel Foundation

Pentester, his company, sells what he knows: all-in-one cybersecurity tooling for vulnerability scanning, data-breach detection, and risk mitigation aimed at businesses that can't afford an in-house security team. The Sentinel Foundation role is the mission-driven side — CTO of a nonprofit applying advanced technology and law-enforcement collaboration against child exploitation and trafficking networks globally. It's an unusual combination: commercial security vendor by day, predator-hunter by calling, and he treats both as the same fight.

What he's known for publicly

Montgomery broke into mainstream awareness through long-form podcast appearances — most notably episode #255 of the Shawn Ryan Show (November 2025), a multi-hour conversation covering his hack of predator networks, the "764" online exploitation group, SIM-swap attacks, spy gadgets, Faraday bags, and public Wi-Fi risks. Clips from his live demonstrations — pulling data off supposedly secure setups in minutes — circulate widely. His message to regular people is consistent and practical: your phone number is a master key (protect it), public Wi-Fi is hostile territory, and most "hacking" is just exploiting human carelessness. Parents especially should read our online safety tips for parents, drawn from the threats he investigates — Roblox, Minecraft, Discord, and the grooming patterns predators use there.

The controversies

No honest profile skips this: Montgomery's work sits in contested territory. Vigilante-adjacent predator exposure raises real questions about evidence handling, entrapment, and due process — questions he addresses by emphasizing law-enforcement partnership over solo action. He's also faced legal battles and media scrutiny, which he's discussed publicly. The fair summary: his technical skill is undisputed, his mission is widely admired, and the methods of the broader predator-exposure movement deserve the scrutiny they get.

Frequently asked questions

Who is Ryan Montgomery?

An American ethical hacker (#1 on TryHackMe's CTF leaderboard), founder of the Pentester cybersecurity platform, and CTO of the Sentinel Foundation.

What does "0day" mean?

It's his handle — a reference to "zero-day" vulnerabilities, previously unknown security flaws. He uses @0dayCTF on X and "0day" on Instagram and YouTube.

Is he a real hacker?

Yes — a white-hat (ethical) hacker: he breaks into systems legally, to find weaknesses before criminals do, and teaches others to do the same.

What is the Sentinel Foundation?

A nonprofit where Montgomery serves as CTO, using technology and law-enforcement collaboration to fight child exploitation and human trafficking.

Where can I follow his work?

His website is ryanmontgomery.me, with @0dayCTF on X and 0day channels on Instagram and YouTube. (This site is not affiliated with him.)

Who Ryan Montgomery is

Montgomery — known online as "0day" — is a legitimate cybersecurity figure, not an internet personality playing one. The credentials: ranked #1 on TryHackMe's Capture The Flag leaderboard, founder of the penetration-testing firm Pentester (based in Boca Raton, Florida), Chief Technology Officer of the Sentinel Foundation (a nonprofit focused on countering child exploitation), and 19+ years in ethical hacking. His public profile rose sharply after his appearance on the Shawn Ryan Show (episode #255, November 2025), where he discussed his work hunting online predators. That's the context for everything on this site: a working security professional who turned his skills toward exposing people who target children online.

The predator-exposure work

Montgomery's best-known public work involves investigating and exposing online predators — using open-source intelligence, undercover online engagement, and technical tracing to identify adults who target minors, then handing evidence to law enforcement. It's the digital equivalent of investigative journalism crossed with private investigation, and it's controversial in exactly the ways you'd expect: supporters see a predator catcher filling gaps in enforcement; critics raise questions about methods, evidence handling, and vigilantism. Our predator-exposure work page covers what he actually does, step by documented step, separate from the mythology.

Online safety: what parents should actually do

Whatever you think of Montgomery's methods, the problem he targets is real — and parents are the first line of defense. The practical list: know which apps your kids use and how their messaging works; keep devices out of bedrooms at night; teach kids that anyone asking for photos or secrecy is a red flag, no exceptions; use parental controls as a backstop, not a replacement for conversation; and make sure your child knows they can tell you anything without punishment — predators rely on shame and secrecy. Our online-safety tips for parents go deeper. No hacker, however skilled, replaces an informed parent.

Ryan Montgomery is what happens when elite hacking skill meets a personal mission — a career built on the idea that the best use of knowing how systems break is keeping people safe. Whether you find him inspiring or unsettling, he's changed how a lot of people think about who's actually protecting the internet's most vulnerable users.