Walk into your next class knowing what to do. Underhook trains your jiu jitsu decisions in 5 minutes a day. Start the path from white belt to blue.
You train two or three times a week. The questions pile up faster than that: why did that sweep work, why do you keep getting caught in the same choke, what were you supposed to do from half guard? Underhook turns those questions into a 5-minute daily habit.
Underhook is a decision trainer for Brazilian Jiu-Jitsu, built the way the best learning apps are built: a structured path, short daily sessions, a streak worth protecting, and a rival who plays for real. Every question drops you into a real position and asks the only thing that matters on the mat: what do you do next?
THE PATH
• A guided path from day-one white belt to blue belt: survival, escapes, guard, passing, sweeps, submissions, and the strategy that connects them
• 1,000+ scenario questions built on 10 core mental models, so you learn principles you can apply from any position, not moves to memorize
• Lessons, quizzes, coach chats, podcast debates and voice lessons: 11 formats keep every session fresh
• Stripe tests along the way, one belt test at the summit. The path ends at blue belt. We mean it.
THE GYM
• Quick Roll: fast sparring quizzes against a gym roster of 12 rivals, from day-one rookie to black belt
• Kat, your AI rival: she plays to win, remembers exactly where your game broke last time, and targets that hole in the next fight (Pro)
• Stamina, streaks, XP and stripes keep the habit honest
• Fully available in English, Portuguese, Spanish and Ukrainian
BUILT FOR REAL TRAINING
Underhook is a supplement, not a substitute. It will not replace mat time and it will not promise you a belt. What it does is make your mat hours stick: 5 minutes a day so the questions you train on the mat actually make sense in class.
Made for adult hobbyists: new white belts drowning in information, blue belts stuck on a plateau, busy people who can't add a fourth class, and anyone sidelined by an injury who refuses to lose their game.
FREE AND PRO
The whole path is free: every lesson, every position, all the way to the belt test. Every new account also starts with 3 days of Underhook Pro, free, with no card and no auto-charge. Pro removes daily limits with unlimited stamina, unlocks Kat the Rival, and adds a second streak freeze. Monthly and annual plans and a one-time lifetime option are available in the app; prices are shown before you pay.
Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. Payment is charged to your Apple Account at confirmation of purchase. Manage or cancel anytime in your Apple Account settings.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://underhook.xyz/privacy
See you on the mats. Oss.
BJJ is not only about physicality, but about mental work as well. An average amount of training is enough to develop your physical abilities, but not enough to fully develop your mental game – obviously, unless you’re a professional who trains for several hours every day. But with Underhook, I can train my brain even while I’m waiting for an appointment to start. And oh boy, it’s beautiful and easy to use! 10/10.
Dangerously addictive!
PLiubov1989
At first, I was skeptical - Duolingo for BJJ? But after a few days, it’s become a really handy tool for developing a “BJJ mindset.” Top-level work from the dev—the usability and attention to detail are just top-notch. Thank you for doing this!
Easy and fun learning
Lucía2011
Started BJJ recently and this app is exactly what I needed. There’s so much to remember after class, and Underhook makes it much easier to understand and review techniques. Really enjoying it so far! 🥋
BJJ people, this is for us!!!!
Ver0wa
Finally something different from endless BJJ videos 😄 Love the way Underhook makes learning feel simple and organized. Great job!
Your home screen keeps your streak, freezes, stamina and XP in one row, with the Roll button right there. After a fight you see when the next one comes. Your progress now shows only what you have earned. Reinstall the app and you land back on your path, gift included. Reminders no longer arrive at midnight or on days you already trained.
Version 1.2.17
The developer, Oleksii Vasyliev, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
Purchases
Contact Info
User Content
Identifiers
Usage Data
Privacy practices may vary, for example, based on the features you use or your age. Learn More
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
Seller
Oleksii Vasyliev
Size
183 MB
Category
Sports
Compatibility
Requires iOS 16.0 or later.
iPhone Requires iOS 16.0 or later.
Mac Requires macOS 13.0 or later and a Mac with Apple M1 chip or later.