# The 21 Days Challenge vs Permission Zero

The clearest difference is in-app purchases: Permission Zero at none against The 21 Days Challenge's 2. Permission Zero also leads on ads (none vs shown) and update cadence (weekly vs monthly). On price, device support and iOS requirement there is nothing between them.

Both are free to download. The 21 Days Challenge sells 2 in-app purchases, starting at $2.99 per month. Permission Zero asks for nothing beyond the download.

The 21 Days Challenge ships an update monthly, Permission Zero weekly. The most recent releases landed on October 25, 2026 and October 20, 2026 respectively.

## The numbers

| Metric | The 21 Days Challenge | Permission Zero |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (568 ratings)](https://appshunter.io/ios/app/the-21-days-challenge/id1485458184/reviews)** | — |
| Number of ratings | **568** | — |
| Positive reviews | 91.7% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Monthly | **Weekly** |
| Monetization | Free with in-app purchases | — |
| Size | 127 MB | 183 MB |
| Requires iOS | **15.0** | 16.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Kati Pereira](https://appshunter.io/developer/1697931524) | [Mosaic Singularity](https://appshunter.io/developer/1892273501) |

## What reviewers say

### The 21 Days Challenge

[App page](https://appshunter.io/ios/app/the-21-days-challenge/id1485458184)

Build lasting habits and transform your life over 21 days with guided challenges. Track your progress, journal your thoughts, and customize your avatar with earned points. Discover new routines for health, productivity, and happiness.

**Highlights:** 21-day habit challenges, Habit tracking, Avatar customization, Daily journaling, Mood tracking, Community feed, Positive affirmations

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove ads month | $2.99 | per month |
| Remove Ads Year | $24.99 | per year |

**What reviewers like**

- 🚀 Simple and motivating
- 👍 Clean design and clear progress tracking
- 🤗 Genuinely helpful and enjoyable to use
- 💫 Positive impact on mental health and habits
- 🌟 Inspirational and encouraging messages

**What reviewers complain about**

- 🔍 Lack of search option in community challenges
- 🔀 Challenges disappear after creation, no way to find them
- 🤖 Too many ads interrupting the experience
- 🎨 App could use more customization options

**Reported bugs**

- Sharing created challenges does not work as expected
- Challenges sometimes disappear from the app

**Requested features**

- Add a search function for community challenges
- Allow users to save and revisit their own created challenges
- Provide more customization options for the app and user profile
- Introduce a widget for easier access to daily tasks


### Permission Zero

[App page](https://appshunter.io/ios/app/permission-zero/id6761979113)

**In-app purchases:** none


## Frequently asked questions

### Is The 21 Days Challenge free?

The 21 Days Challenge is free to download, with in-app purchases available.

### Is Permission Zero free?

Permission Zero is free to download, with no in-app purchases.

### Do The 21 Days Challenge or Permission Zero have ads?

The 21 Days Challenge shows ads; Permission Zero does not.

### Which is updated more often, The 21 Days Challenge or Permission Zero?

The 21 Days Challenge ships an update monthly, and Permission Zero weekly. Most recently, The 21 Days Challenge was updated on October 25, 2026 and Permission Zero on October 20, 2026.

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