# Starfy vs Constraint Engine

The clearest difference is update cadence: Constraint Engine at daily against Starfy's every 3 weeks. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Starfy sells 2 in-app purchases, starting at $19.99 per month and Constraint Engine sells 2 in-app purchases, starting at $4.99 per month. Whichever you choose, the download price is not the number that matters.

Starfy ships an update every 3 weeks, Constraint Engine daily. The most recent releases landed on October 23, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Starfy | Constraint Engine |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Daily** |
| Monetization | Subscription | — |
| Size | 546 MB | 10 MB |
| Requires iOS | **15.1** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [BEINGBEING PRIVATE LIMITED](https://appshunter.io/developer/1879737061) | [Mark Barker](https://appshunter.io/developer/1896741919) |

## What reviewers say

### Starfy

[App page](https://appshunter.io/ios/app/starfy-spark-curiosity/id6767147544)

This app guides children's growth through curiosity, creativity, and self-expression. It offers interactive features like co-creating stories, exploring the world through photos, and practicing social skills. Parents receive personalized insights and suggestions to support their child's development.

**Highlights:** Co-create stories, Explore with Magic Camera, Practice social skills, Engage in creative play, Personalized parenting guidance, Growth insights for parents

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $19.99 | per month |
| Yealy | $119.99 | per year |


### Constraint Engine

[App page](https://appshunter.io/ios/app/constraint-engine/id6772520332)

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Constraint Engine Pro | $4.99 | per month |
| Constraint Engine Pro | $29.99 | per year |


## Frequently asked questions

### Is Starfy free?

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

### Is Constraint Engine free?

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

### Do Starfy or Constraint Engine have ads?

Neither Starfy nor Constraint Engine shows ads.

### Which is updated more often, Starfy or Constraint Engine?

Starfy ships an update every 3 weeks, and Constraint Engine daily. Most recently, Starfy was updated on October 23, 2026 and Constraint Engine on October 5, 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.*