# Unfog vs HeyKids.ai

The clearest difference is update cadence: Unfog at every 2 days against HeyKids.ai's every 5 days. HeyKids.ai's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.0). On price, ads and in-app purchases there is nothing between them.

Both are free to download. Unfog sells 3 in-app purchases, starting at $2.99 per 7 days and HeyKids.ai sells 1 in-app purchase, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

Unfog ships an update every 2 days, HeyKids.ai every 5 days. The most recent releases landed on October 25, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Unfog | HeyKids.ai |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 2 days** | Every 5 days |
| Size | 80 MB | 79 MB |
| Requires iOS | 17.0 | **15.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [BITSEC SP. Z O.O.](https://appshunter.io/developer/1801990616) | [HEYLABS, INC](https://appshunter.io/developer/6776575127) |

## What reviewers say

### Unfog

[App page](https://appshunter.io/ios/app/unfog-feynman-study-notes/id6776245365)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Unfog weekly | $2.99 | per 7 days |
| Unfog Monthly | $17.99 | per month |
| Unfog Annual | $29.99 | per year |


### HeyKids.ai

[App page](https://appshunter.io/ios/app/heykidsai/id6776575125)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| One Month Subscription | $3.99 | per month |


## Frequently asked questions

### Is Unfog free?

Unfog is free to download, with in-app purchases available.

### Is HeyKids.ai free?

HeyKids.ai is free to download, with in-app purchases available.

### Do Unfog or HeyKids.ai have ads?

Neither Unfog nor HeyKids.ai shows ads.

### Which is updated more often, Unfog or HeyKids.ai?

Unfog ships an update every 2 days, and HeyKids.ai every 5 days. Most recently, Unfog was updated on October 25, 2026 and HeyKids.ai on October 24, 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.*