# O3 Alarm vs AlarmSMS Controller

The clearest difference is in-app purchases: O3 Alarm at none against AlarmSMS Controller's 1. O3 Alarm also leads on iOS requirement (7.0 vs 16.0). AlarmSMS Controller's advantage is update cadence (monthly vs every 7 months). On price, ads and device support there is nothing between them.

Both are free to download. AlarmSMS Controller sells 1 one-off in-app purchase. O3 Alarm asks for nothing beyond the download.

O3 Alarm ships an update every 7 months, AlarmSMS Controller monthly. The most recent releases landed on October 10, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | O3 Alarm | AlarmSMS Controller |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/o3-alarm/id950579931/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 7 months | **Monthly** |
| Monetization | Free | — |
| Size | 71 MB | 52 MB |
| Requires iOS | **7.0** | 16.0 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Chuango Security Technology Corporation](https://appshunter.io/developer/534068551) | [George Alexandrou](https://appshunter.io/developer/1875566334) |

## What reviewers say

### O3 Alarm

[App page](https://appshunter.io/ios/app/o3-alarm/id950579931)

This security system app provides 360° protection for homes and small businesses. It allows remote monitoring, control of sensors, and customizable alerts for intrusions, floods, smoke, or gas. Manage your system, set routines, and receive notifications for enhanced safety and convenience.

**Highlights:** 360° protection with up to 50 wireless sensors, Intrusion, flood, smoke, and gas detection alerts, Customizable entry and exit delays, Adjustable siren duration and volume (up to 95 dB), Smartphone, remote control, and panel interaction, RFID tag management and SMS notifications, Supports multiple users and smartphones

**In-app purchases:** none


### AlarmSMS Controller

[App page](https://appshunter.io/ios/app/alarmsms-controller/id6773087060)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| AlarmSMS Pro | $4.99 | one-time |


## Frequently asked questions

### Is O3 Alarm free?

O3 Alarm is free to download, with no in-app purchases.

### Is AlarmSMS Controller free?

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

### Do O3 Alarm or AlarmSMS Controller have ads?

Neither O3 Alarm nor AlarmSMS Controller shows ads.

### Which is updated more often, O3 Alarm or AlarmSMS Controller?

O3 Alarm ships an update every 7 months, and AlarmSMS Controller monthly. Most recently, O3 Alarm was updated on October 10, 2026 and AlarmSMS Controller on October 15, 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.*