# Overlap vs Smart Purifier

The clearest difference is review sentiment: Overlap at 67% against Smart Purifier's 0%. Overlap also leads on rating (4.8 vs 1.0) and ratings volume (871 vs 1). Smart Purifier's advantage is update cadence (fortnightly vs every 3 months) and iOS requirement (11.0 vs 15.0). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Overlap holds the better App Store score, 4.8 against 1.0. That said, the two scores are not equally well evidenced: Overlap has 871 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 67% of Overlap's written reviews are positive against 0% of Smart Purifier's.

Overlap ships an update every 3 months, Smart Purifier fortnightly. The most recent releases landed on October 22, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Overlap | Smart Purifier |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (871 ratings)](https://appshunter.io/ios/app/overlap-world-clock/id1516950324/reviews)** | [1.0 (1 ratings)](https://appshunter.io/ios/app/smart-purifier/id1535735160/reviews) |
| Number of ratings | **871** | 1 |
| Positive reviews | **67.3% of reviews** | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 months | **Fortnightly** |
| Monetization | Free | Free |
| Size | 71 MB | 115 MB |
| Requires iOS | 15.0 | **11.0** |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Bonobo](https://appshunter.io/developer/666155611) | [VIETTEL GROUP](https://appshunter.io/developer/1529233160) |

## What reviewers say

### Overlap

[App page](https://appshunter.io/ios/app/overlap-world-clock/id1516950324)

Easily find optimal meeting times across different time zones with a visual graph. Set custom availability for each location and sync with your calendar to avoid scheduling conflicts. Share convenient times directly from the app.

**Highlights:** Visual Overlap Graph for meeting times, Customizable availability hours per time zone, Calendar event integration, Multiple time zone display, Time zone renaming, Lock Screen Standby Mode widget

**Features:** Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 💡 Elegant and intuitive interface
- 🚀 Helpful for coordinating meetings across time zones
- 👍 Useful for tracking time differences globally
- 👍 Simple and easy to use
- 👍 Beautiful and sleek design

**What reviewers complain about**

- 🐛 Widget not working
- 🐛 Timezone data not always accurate
- 🐛 Duplicate timezone entries
- 🐛 App crashes and freezes
- 🔋 High CPU usage on Mac

**Reported bugs**

- Timezone data not updating correctly
- Inability to delete unwanted timezones
- Inconsistent behavior across platforms
- Typing issues on Mac version

**Requested features**

- Add option to reorder timezones
- Implement 24-hour clock display
- Allow customization of colors and backgrounds
- Integrate with calendar for scheduling
- Add weather information for each timezone


### Smart Purifier

[App page](https://appshunter.io/ios/app/smart-purifier/id1535735160)

Monitor and control your Smart Purifier air quality device. View real-time air quality data and adjust settings remotely. Ensure a healthy living environment with this connected appliance management tool.

**Highlights:** Remote device control, Real-time air quality monitoring, Device settings adjustment, Air purification management, Connected appliance integration

**In-app purchases:** none


## Frequently asked questions

### Is Overlap free?

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

### Is Smart Purifier free?

Smart Purifier is free to download, with no in-app purchases.

### Which has better reviews, Overlap or Smart Purifier?

Overlap is rated higher. Overlap averages 4.8 out of 5 from 871 ratings, while Smart Purifier averages 1.0 from 1 ratings.

### Do Overlap or Smart Purifier have ads?

Neither Overlap nor Smart Purifier shows ads.

### Which is updated more often, Overlap or Smart Purifier?

Overlap ships an update every 3 months, and Smart Purifier fortnightly. Most recently, Overlap was updated on October 22, 2026 and Smart Purifier on October 1, 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.*