# Defapp vs Koi

The clearest difference is in-app purchases: Koi at none against Defapp's 1. On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Defapp sells 1 in-app purchase, starting at $2.99 per year. Koi asks for nothing beyond the download.

Both ship on a similar rhythm, roughly fortnightly. The most recent releases landed on November 3, 2026 and October 24, 2026 respectively.

## The numbers

| Metric | Defapp | Koi |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 80.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Fortnightly | Fortnightly |
| Monetization | Free with in-app purchases | — |
| Size | 13 MB | 6 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | **iPhone, iPad, iPod, Apple Watch** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [macremer](https://appshunter.io/developer/455580164) | [Peter Nickel](https://appshunter.io/developer/6796957510) |

## What reviewers say

### Defapp

[App page](https://appshunter.io/ios/app/defapp-personal-security/id1536395733)

This app provides discreet personal security for individuals feeling unsafe or threatened. It allows users to quickly call for help, share their location, and activate defense mechanisms like strobe lights and alarms, even without speaking. Designed for situations where you're alone, it offers peace of mind on the go.

**Highlights:** Discreet emergency contact notification, Real-time location sharing, Strobe light for defense, Loud alarm to deter attackers, Automatic video recording, Voice command activation, Apple Watch integration

**Features:** macOS Compatibility, Family Sharing, Apple Watch app, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Defapp Personal Security Pro | $2.99 | per year |


### Koi

[App page](https://appshunter.io/ios/app/koi-manager/id6796957508)

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

**In-app purchases:** none


## Frequently asked questions

### Is Defapp free?

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

### Is Koi free?

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

### Do Defapp or Koi have ads?

Neither Defapp nor Koi shows ads.

### Which is updated more often, Defapp or Koi?

Defapp ships an update fortnightly, and Koi fortnightly. Most recently, Defapp was updated on November 3, 2026 and Koi on October 24, 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.*