# Rays vs Seize Light

The clearest difference is in-app purchases: Seize Light at none against Rays's 2. Rays's advantage is ads (none vs shown) and update cadence (every 5 days vs every 2 weeks). On price and device support there is nothing between them.

Both are free to download. Rays sells 2 in-app purchases, starting at $4.99 per month. Seize Light asks for nothing beyond the download.

Rays ships an update every 5 days, Seize Light every 2 weeks. The most recent releases landed on October 24, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Rays | Seize Light |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (7 ratings)](https://appshunter.io/ios/app/rays-auto-vitamin-d-tracking/id6752499967/reviews)** | — |
| Number of ratings | **7** | — |
| Positive reviews | 75.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | **Every 5 days** | Every 2 weeks |
| Monetization | Free with in-app purchases | — |
| Size | 58 MB | 35 MB |
| Requires iOS | **15.1** | 18.0 |
| Devices | **iPhone, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Rays Health Technologies LLC](https://appshunter.io/developer/1829292925) | [sebastian totte](https://appshunter.io/developer/1819107580) |

## What reviewers say

### Rays

[App page](https://appshunter.io/ios/app/rays-auto-vitamin-d-tracking/id6752499967)

Automatically tracks your body's vitamin D synthesis from sun exposure. Get personalized recommendations for optimal timing and duration to maintain energy, mood, and skin health year-round without manual logging.

**Highlights:** Automatic vitamin D synthesis tracking, Personalized health intelligence, Smart sun exposure recommendations, Progress tracking and health insights, Apple Health integration, Minimal battery usage

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Rays - Auto Vitamin D Tracker | $4.99 | per month |
| Rays - Auto Vitamin D Tracker | $19.99 | per year |


### 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 Rays free?

Rays 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 Rays or Seize Light have ads?

Seize Light shows ads; Rays does not.

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

Rays ships an update every 5 days, and Seize Light every 2 weeks. Most recently, Rays was updated on October 24, 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.*