StayFree is the utilitarian hero. It is the best choice if your budget is $0. It offers incredible value, supporting almost every platform (including Linux, iOS, and Android) and offering cross-device syncing completely for free. It is a tracker first, and a blocker second.
Zentra is the specialist. It costs money for premium features because it offers a more curated, polished experience with better privacy (no data business model), deeper analytics, and strict mode that makes its blocks hard to break.
Quick Comparison
| Feature | Zentra | StayFree |
|---|---|---|
| Best For | Android Analytics & Strict Mode | Cross-Platform Tracking |
| Pricing | $3.99/mo | 100% FREE |
| Free Tier | Excellent | Unbeatable |
| Key Feature | Strict Mode | Free Desktop + Mobile Sync |
| Platforms | Android only | Android, iOS, Win, Mac, Linux |
| Desktop | No | Native Apps |
| Strict Mode | Yes | No |
In-Depth Feature Breakdown
Privacy & Business Model
StayFree is free. “If you’re not paying for the product, you are the product.” While StayFree is reputable, they are owned by Sensor Tower, a market intelligence company. Data is their business.
Zentra charges a subscription ($3.99/mo). You are the customer, not the product. Your data is yours, and the business model is straightforward: you pay for a tool that helps you.
The Block
Zentra enforces blocks at the system level. Strict mode adds uninstall protection and permission lockdown, so your focus schedules can’t be switched off in a moment of weakness.
StayFree is a traditional tracking app. It monitors your usage across all platforms but doesn’t modify your device’s interface.
Desktop Support
This is where StayFree excels. It offers native desktop applications for Windows, Mac, and Linux, providing comprehensive screen time tracking across all your devices.
Zentra is mobile-focused and does not offer desktop tracking. If you work on a computer and want unified tracking, StayFree has the advantage.
Final Verdict
Choose Zentra If…
- You want enforcement: Strict mode keeps your focus schedules unbreakable.
- You need detailed analytics: Granular hourly heatmaps provide deeper insights into your usage patterns.
- You prioritize privacy: Pay $3.99/mo to be the customer, not the product being sold.
- You’re mobile-only: You don’t need desktop tracking and focus solely on phone usage.
Choose StayFree If…
- You have an iPhone: StayFree supports iOS; Zentra is Android-only.
- You want everything free: Zero subscription costs with comprehensive features.
- You work on desktop: Native apps for Windows, Mac, and Linux provide full computer tracking.
- You need cross-platform sync: Free syncing between mobile (iOS & Android) and desktop.
- You’re okay with the trade-off: Free service means your usage data supports their business model (owned by Sensor Tower).