# SunSync vs Seize Light

The clearest difference is in-app purchases: Seize Light at none against SunSync's 2. SunSync's advantage is ads (none vs shown). On price, update cadence, device support and iOS requirement there is nothing between them.

Both are free to download. SunSync sells 2 in-app purchases, starting at $1.99 per year. Seize Light asks for nothing beyond the download.

SunSync ships an update every 3 weeks, Seize Light every 2 weeks. The most recent releases landed on September 25, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | SunSync | Seize Light |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 3 weeks | **Every 2 weeks** |
| Size | 22 MB | 35 MB |
| Requires iOS | **17.6** | 18.0 |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Marta Rodriguez](https://appshunter.io/developer/1873973295) | [sebastian totte](https://appshunter.io/developer/1819107580) |

## What reviewers say

### SunSync

[App page](https://appshunter.io/ios/app/sunsync-circadian-tracker/id6762293528)

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Year | $1.99 | per year |
| Lifetime | $2.99 | one-time |


### Seize Light

[App page](https://appshunter.io/ios/app/seize-light/id6784576883)

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

**In-app purchases:** none


## Frequently asked questions

### Is SunSync free?

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

### Is Seize Light free?

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

### Do SunSync or Seize Light have ads?

Seize Light shows ads; SunSync does not.

### Which is updated more often, SunSync or Seize Light?

SunSync ships an update every 3 weeks, and Seize Light every 2 weeks. Most recently, SunSync was updated on September 25, 2026 and Seize Light on October 12, 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.*