Hold It vs ZeroDay Dev

Tired of monthly or yearly subscriptions? Competitors charge thousands of yen every year. With Hold It, pay just $9.99 ONCE, and it's yours forever.No recurring fees. No hidden costs. 100% private. Trying to study but keep checking your phone? You open your notes, then reach for social media without thinking. One video turns into thirty minutes. Your focus disappears before you even realize it. Hold It is a simple app designed to help you stay focused during study time. Stay focused without complicated setups Hold It removes distractions so you can concentrate on what matters. Choose the apps you want to limit. Set a daily time limit or number of launches. That is all. No shortcuts. No automations. No complex rules. Just a simple system that helps you stay on track. Designed for students and deep work Hold It is perfect for: – Students preparing for exams – People doing deep work – Anyone who wants a distraction-free study session Instead of relying on willpower, you change your environment. No subscriptions. Pay once. Use forever. Most productivity apps charge monthly or yearly subscriptions. Hold It is different. You pay once and keep using it forever. No recurring payments. No hidden upgrades. Simple setup in under one minute Select the apps you want to limit. Set your rules. Start focusing. No technical knowledge needed. Works fully offline Your data stays on your device. Nothing is uploaded. Nothing is shared. Focus is not about discipline If you struggle to focus, it is not because you are lazy. Apps are designed to keep you engaged. Hold It helps you take back control by removing distractions. Simple. Private. Effective.

Learn to break things—before attackers do. ZeroDay Dev teaches secure coding and blockchain security through 4,000+ hands-on challenges. Learn from 120+ real-world exploits: Beanstalk, Indexed Finance, bZx, VeilCash, Sigma.Money, Bybit, and more. Each exploit is linked to verified incident records so you learn from actual on-chain events, not hypotheticals. Practice — Build exploit intuition without reading docs. Tap vulnerable lines, drag tokens into code, get instant feedback. Filter by domain (Exploits, Solidity, Rust, DeFi, Solana) or difficulty. Exercises — Full code challenges with reference solutions. Deeper dives when you're ready. Exam — Prepare for real security assessments. Timed tests across domains with performance tracking. Memory-match decks for opcodes, EIPs, and security terms. Deep Dive Hub — Curated learning tracks for Web2, Web3, Rust, ZK Proofs, and Trading. Recommended tracks driven by your weak areas. Build your own from bookmarks or missed questions. Streaks & XP — Stay consistent and level up. Daily streaks, badges, and progression keep you coming back. Offline-first — Learn on the subway, no Wi‑Fi needed. All content lives on your device. No account required—start immediately. Covers reentrancy, oracle manipulation, flash loans, proxy races, ZK trusted setup, and more. Rust, Solidity, DeFi, Solana & cybersecurity.