# Interval Timer HIIT Workout vs Sentinel by Solace Group

The clearest difference is in-app purchases: Sentinel by Solace Group at none against Interval Timer HIIT Workout's 5. Sentinel by Solace Group also leads on ads (none vs shown) and iOS requirement (15.1 vs 18.0). Interval Timer HIIT Workout's advantage is update cadence (weekly vs fortnightly). On price and device support there is nothing between them.

Both are free to download. Interval Timer HIIT Workout sells 5 in-app purchases, starting at $1.99 per month. Sentinel by Solace Group asks for nothing beyond the download.

Interval Timer HIIT Workout ships an update weekly, Sentinel by Solace Group fortnightly. Both last shipped on October 25, 2026.

## The numbers

| Metric | Interval Timer HIIT Workout | Sentinel by Solace Group |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (339 ratings)](https://appshunter.io/ios/app/interval-timer-hiit-workout/id6741055716/reviews)** | — |
| Number of ratings | **339** | — |
| Positive reviews | 66.7% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | **Weekly** | Fortnightly |
| Monetization | Free with in-app purchases | — |
| Size | 98 MB | 214 MB |
| Requires iOS | 18.0 | **15.1** |
| Devices | **iPhone, iPad, Apple Watch** | iPhone, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Roli LLC](https://appshunter.io/developer/1792785559) | [Wellifiy Pty Ltd](https://appshunter.io/developer/1544906420) |

## What reviewers say

### Interval Timer HIIT Workout

[App page](https://appshunter.io/ios/app/interval-timer-hiit-workout/id6741055716)

Customize your HIIT and Tabata workouts with this versatile interval timer. Features AI voice cues from celebrity personalities, music integration, and Apple Health syncing. Track your progress and share routines with ease.

**Highlights:** Customizable work/rest periods, AI voice cues from celebrity personalities, Music integration, Apple Health & Apple Watch sync, Save and organize workouts, Real-time exercise on-screen cues, Share workouts with others

**Features:** Family Sharing, Apple Watch app

**In-app purchases (5)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Subscription | $1.99 | per month |
| Monthly Subscription | $2.99 | per month |
| Yearly Subscription | $29.99 | per year |
| Yearly Subscription | $29.99 | per year |
| One Time Purchase | $19.99 | one-time |


### Sentinel by Solace Group

[App page](https://appshunter.io/ios/app/sentinel-by-solace-group/id6747097357)

**Features:** macOS Compatibility, Apple Wallet, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Interval Timer HIIT Workout free?

Interval Timer HIIT Workout is free to download, with in-app purchases available.

### Is Sentinel by Solace Group free?

Sentinel by Solace Group is free to download, with no in-app purchases.

### Do Interval Timer HIIT Workout or Sentinel by Solace Group have ads?

Interval Timer HIIT Workout shows ads; Sentinel by Solace Group does not.

### Which is updated more often, Interval Timer HIIT Workout or Sentinel by Solace Group?

Interval Timer HIIT Workout ships an update weekly, and Sentinel by Solace Group fortnightly. Most recently, Interval Timer HIIT Workout was updated on October 25, 2026 and Sentinel by Solace Group on October 25, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*