# Prompt 21 vs ObsiKO

The clearest difference is device support: ObsiKO at 4 against Prompt 21's 2. On price, update cadence, ads and in-app purchases there is nothing between them.

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

Prompt 21 ships an update every 4 days, ObsiKO every 6 days. The most recent releases landed on October 11, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | Prompt 21 | ObsiKO |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[5.0 (1 ratings)](https://appshunter.io/ios/app/obsiko-ai-note-plus-mindmap/id6783405451/reviews)** |
| Number of ratings | — | **1** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 days** | Every 6 days |
| Monetization | — | Free |
| Size | 39 MB | 77 MB |
| Requires iOS | 15.1 | 15.1 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod, Apple Watch** |
| Age rating | 17+ | 4+ |
| Developer | [Cheuk Hin Wong](https://appshunter.io/developer/1833016596) | [Hyojin Kim](https://appshunter.io/developer/6783405453) |

## What reviewers say

### Prompt 21

[App page](https://appshunter.io/ios/app/prompt-21/id6752573818)

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

**In-app purchases:** none


### ObsiKO

[App page](https://appshunter.io/ios/app/obsiko-ai-note-plus-mindmap/id6783405451)

This app integrates writing, knowledge management, and mind mapping with AI assistance. It supports various file formats and offers unique features for Korean language users, including a focus timer and GitHub syncing for secure data management.

**Highlights:** AI-assisted writing and mind mapping, Supports Obsidian vaults (.md, .canvas, .base), Korean dictionary and spell checker, Lock Screen focus timer, GitHub sharing and syncing, Automatic note connection and organization, Infinite mind-map canvas with Apple Pencil support

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support, iPhone Duo support

**In-app purchases:** none


## Frequently asked questions

### Is Prompt 21 free?

Prompt 21 is free to download, with no in-app purchases.

### Is ObsiKO free?

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

### Do Prompt 21 or ObsiKO have ads?

Neither Prompt 21 nor ObsiKO shows ads.

### Which is updated more often, Prompt 21 or ObsiKO?

Prompt 21 ships an update every 4 days, and ObsiKO every 6 days. Most recently, Prompt 21 was updated on October 11, 2026 and ObsiKO on October 25, 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.*