Choosing a posture app shouldn’t require a spreadsheet. If you’ve narrowed it down to SitApp and BLiiNK, this comparison will help you decide.
Full disclosure: I built SitApp. I’ll be honest about where BLiiNK does things differently and where each app falls short. You deserve a straight comparison.
Quick Comparison
| Feature | SitApp | BLiiNK |
|---|---|---|
| Platforms | Mac, Windows, Linux | Mac (M1/M2 only), Windows |
| Free tier | Yes (core features) | Free trial only |
| Paid price | $3.99/month | ~$8.33/month |
| AI posture detection | Yes (on-device) | Yes (on-device) |
| Blink tracking | No | Yes |
| Screen distance | No | Yes |
| Break reminders | Yes | Yes |
| Privacy | 100% on-device | On-device processing |
| Linux support | Yes | No |
| Open calibration | Custom per location | Fixed model |
Platform Support
SitApp runs on Mac, Windows, and Linux. If you switch between operating systems or use Linux as your daily driver, SitApp is one of the only AI posture apps that supports all three.
BLiiNK supports Mac and Windows, but the Mac version requires an M1 or M2 chip. If you’re on an older Intel Mac, BLiiNK won’t work for you.
Winner: SitApp — broader platform support, especially for Linux users and older Macs.
Pricing
SitApp has a genuinely free tier that includes core posture monitoring. The Pro plan at $3.99/month unlocks advanced features like location-aware detection and detailed analytics.
BLiiNK offers a free trial but requires a paid subscription to continue using the app. Pricing starts around $8.33/month for the personal plan.
Winner: SitApp — free tier available, and Pro costs less than half of BLiiNK’s personal plan.
Posture Detection
Both apps use AI and your webcam to detect posture in real time. Neither sends webcam data to external servers.
SitApp uses a calibration system where you teach the app what “good posture” looks like for you. You can create different calibrations for different setups (standing desk, couch, office chair). This means it adapts to your body and workspace rather than enforcing a universal standard.
BLiiNK uses a fixed AI model to detect posture deviations. It monitors your spine alignment and alerts you when it detects slouching.
Winner: Tie — both do the core job. SitApp’s per-location calibration is more flexible; BLiiNK’s approach is more hands-off.
Extra Features
BLiiNK includes blink rate tracking and screen distance monitoring, which SitApp doesn’t have. If eye strain is a major concern for you, BLiiNK covers more ground.
SitApp focuses purely on posture but goes deeper: location-aware detection (different calibrations for different setups), a streak/achievement system, and a mini monitoring window that stays out of your way.
Winner: BLiiNK for breadth of wellness features. SitApp for depth of posture features.
Privacy
Both apps process webcam data locally on your device. Neither uploads video or images to external servers.
SitApp is explicit about this: all AI inference runs on-device using TensorFlow.js. No webcam data leaves your computer, ever.
BLiiNK also processes locally and markets itself as privacy-focused.
Winner: Tie — both take privacy seriously.
Who Should Pick What
Choose SitApp if:
- You use Linux
- You want a free tier that actually works
- You switch between multiple desk setups
- You want the lowest price for a Pro plan
- You have an older Intel Mac
Choose BLiiNK if:
- Blink tracking and screen distance matter to you
- You prefer a hands-off setup (no calibration)
- You’re on a newer Mac or Windows only
- You want a broader wellness toolkit beyond just posture
Bottom Line
SitApp and BLiiNK both solve the same core problem: they remind you to sit up straight. SitApp gives you more control, broader platform support, and a lower price. BLiiNK offers a wider set of wellness features beyond posture. Your choice comes down to what you value most.
Ready to try SitApp? Download it free for Mac, Windows, or Linux.
FAQ
Is BLiiNK free?
BLiiNK offers a free trial, but requires a paid subscription (starting around $8.33/month) to keep using the app. SitApp has a permanently free tier with core posture monitoring.
Does BLiiNK work on Linux?
No. BLiiNK supports Mac (M1/M2 chips only) and Windows. SitApp is one of the few AI posture apps available on Linux.
Which posture app is more private?
Both SitApp and BLiiNK process webcam data entirely on your device. Neither uploads video or images to external servers.
Can I use SitApp and BLiiNK at the same time?
Technically yes, but there’s no reason to. Both use your webcam, and running two posture apps simultaneously would send you double the alerts. Pick one and stick with it.