# Crescent Keys vs PolyInvert

The clearest difference is in-app purchases: Crescent Keys at none against PolyInvert's 1. Crescent Keys also leads on ads (none vs shown) and iOS requirement (11.0 vs 17.0). PolyInvert's advantage is update cadence (daily vs fortnightly). On price and device support there is nothing between them.

Both are free to download. PolyInvert sells 1 one-off in-app purchase. Crescent Keys asks for nothing beyond the download.

Crescent Keys ships an update fortnightly, PolyInvert daily. The most recent releases landed on October 3, 2026 and October 7, 2026 respectively.

## The numbers

| Metric | Crescent Keys | PolyInvert |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Fortnightly | **Daily** |
| Size | 4 MB | 8 MB |
| Requires iOS | **11.0** | 17.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 9+ | 4+ |
| Developer | [Quoc Dat Nguyen](https://appshunter.io/developer/1680757392) | [ADAM MICHAEL OGDEN](https://appshunter.io/developer/1854648813) |

## What reviewers say

### Crescent Keys

[App page](https://appshunter.io/ios/app/crescent-keys-video-time-note/id6447262729)

**In-app purchases:** none


### PolyInvert

[App page](https://appshunter.io/ios/app/polyinvert/id6755578020)

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Remove Ads | $2.99 | one-time |


## Frequently asked questions

### Is Crescent Keys free?

Crescent Keys is free to download, with no in-app purchases.

### Is PolyInvert free?

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

### Do Crescent Keys or PolyInvert have ads?

PolyInvert shows ads; Crescent Keys does not.

### Which is updated more often, Crescent Keys or PolyInvert?

Crescent Keys ships an update fortnightly, and PolyInvert daily. Most recently, Crescent Keys was updated on October 3, 2026 and PolyInvert on October 7, 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.*