# THUNDER vs Secure Watermark

The clearest difference is update cadence: Secure Watermark at every 2 weeks against THUNDER's every 11 months. THUNDER's advantage is iOS requirement (14.0 vs 17.0). On price, ads, in-app purchases and device support there is nothing between them.

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

THUNDER ships an update every 11 months, Secure Watermark every 2 weeks. The most recent releases landed on September 26, 2026 and June 1, 2026 respectively.

## The numbers

| Metric | THUNDER | Secure Watermark |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[1.0 (1 ratings)](https://appshunter.io/ios/app/secure-watermark/id6504274596/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 11 months | **Every 2 weeks** |
| Monetization | — | Free |
| Size | 54 MB | 2 MB |
| Requires iOS | **14.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Rubik Smart Solutions](https://appshunter.io/developer/1483981076) | [泽海 黄](https://appshunter.io/developer/1069894245) |

## What reviewers say

### THUNDER

[App page](https://appshunter.io/ios/app/thunder/id1567021141)

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

**In-app purchases:** none


### Secure Watermark

[App page](https://appshunter.io/ios/app/secure-watermark/id6504274596)

Easily protect your sensitive documents and digital creations from unauthorized use. Add custom text, image, or handwritten signature watermarks to photos, IDs, and artwork. Offers advanced customization for text and image placement, with ID mode for seamless document protection.

**Highlights:** Rich text watermarks with full customization, Image watermarks with adjustable transparency, Handwritten signature watermarks, ID mode for secure document protection, Export as image or PDF at 300 DPI, Watermark management list

**In-app purchases:** none


## Frequently asked questions

### Is THUNDER free?

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

### Is Secure Watermark free?

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

### Do THUNDER or Secure Watermark have ads?

Neither THUNDER nor Secure Watermark shows ads.

### Which is updated more often, THUNDER or Secure Watermark?

THUNDER ships an update every 11 months, and Secure Watermark every 2 weeks. Most recently, THUNDER was updated on September 26, 2026 and Secure Watermark on June 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.*