FitBetween vs CastleFit
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
FitBetween
This app intelligently finds gaps in your calendar to generate AI-powered workouts tailored to your available time. It requires no equipment and fits movement into your existing schedule, making fitness accessible for busy individuals.
- AI workout generation
- Calendar integration
- Time-based workouts
- No equipment needed
- Privacy-focused
- Streak tracking
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The fitness app for people whose calendars actually run their lives. FitBetween reads your Apple Calendar, finds the openings between your meetings, and generates AI workouts sized to fit those exact gaps. No gym. No equipment. No 90-minute commitment. Just movement that fits the time you actually have. HOW IT WORKS - Connect your Apple/ Google Calendar (read-only, stays on your device) - See your day as openings - 15 minutes here, 45 there - Tap one. Pick a duration. Pick your space. Get an AI-generated workout instantly - Move. Track your streak. Repeat tomorrow. BUILT FOR PEOPLE WHO DON'T HAVE TIME This was built for the founder, the parent, the working person whose Sundays show "12 hours of social media use" and whose calendar shows three free hours they didn't notice. The lie isn't that you're too busy. The lie is that exercise has to be a separate thing you carve out time for. It doesn't. WHAT MAKES IT DIFFERENT - Reads your real calendar — not a generic "schedule a workout" reminder - AI workouts that actually fit your time, not generic 30-min sessions - Three space modes (Small, Medium, Open) so the workout matches where you are - Reminders 5 minutes before each opening - Streak tracking with a 24-hour grace window for the inevitable bad days - Privacy first: calendar data never leaves your phone NOT YOUR USUAL FITNESS APP No social feed. No leaderboard. No body comparisons. No subscription. No ads. Just you, your calendar, and the time you didn't know you had. Made by an indie developer who got tired of fitness apps that didn't fit a real life. -Deston, founder Questions or feedback: hello@fitbetween.app
CastleFit
This app offers guided stretching and mobility sessions to relieve pain, improve flexibility, and aid recovery. It provides routines for various needs, from injury recovery to pre-training warm-ups, all accessible at home.
- Guided stretch and mobility sessions
- Targeted relief for specific body parts
- HD instructional videos
- Sessions organized by age, ability, and goals
- Active and passive stretching routines
- Device lineup browsing and purchasing
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Relieve pain. Improve flexibility. Recover faster. Castle Fit brings the full CastleFlexx experience to your phone — guided stretch and mobility sessions built around the device that helps treat the root causes of lower back pain, plantar fasciitis, tight calves, hamstring tightness, and limited mobility. Whether you are recovering from an injury, loosening up before training, or building a daily movement habit, Castle Fit gives you a clear, follow-along routine you can do at home. WHAT YOU GET ◆ Dozens of instructional HD videos and relaxing flows ◆ Sessions organized by your age, ability, and goals ◆ Guided programs from leading trainers and therapists ◆ Active and passive stretching routines for full-body mobility ◆ Targeted relief for calves, hamstrings, hips, lower back, and feet SHOP THE FULL RANGE ▸ Browse the complete CastleFlexx device lineup and accessories ▸ Save your favorites to a wishlist ▸ Fast, secure checkout ▸ Track your orders from purchase to delivery ▸ Get updates on new arrivals and restocks TRUSTED BY EXPERTS AND ATHLETES CastleFlexx is recommended by clinicians and chiropractors and used by professional athletes as part of their recovery. The device pairs stretching with core strengthening for a balanced, controlled experience. BUILT FOR YOUR ROUTINE Follow along at your own pace, choose sessions that match how your body feels today, and come back to the flows that work best for you. Everything is designed to keep you moving, mobile, and pain-free. Download Castle Fit and start moving better today.
Screenshots
Verdict
The clearest difference is rating: FitBetween at 5.0 against CastleFit's 2.0. FitBetween also leads on update cadence (every 2 days vs every 2 weeks). On price, ratings volume, ads and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
FitBetween holds the better App Store score, 5.0 against 2.0. Both are backed by a comparable volume of ratings — 1 and 2 respectively.
FitBetween ships an update every 2 days, CastleFit every 2 weeks. Both last shipped on November 5, 2026.
| Parameter | FitBetween | CastleFit |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | 2.0 (2 ratings) |
| Number of ratings | 1 | 2 — better |
| Update frequency | Every 2 days — better | Every 2 weeks |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | Free |
| Devices | iPhone, iPod | iPhone, iPad, iPod — better |
| Requires iOS | 15.1 | 15.1 |
| Further details — not scored | ||
| Size | 37 MB | 45 MB |
| Age rating | 12+ | 4+ |
| Developer | Deston Evans | Castle Flexx |
Customer experience
FitBetween
CastleFit
In-app purchases
FitBetween
No in-app purchases
CastleFit
No in-app purchases









