# SLS vs 리드키(ReadKey)

The clearest difference is update cadence: 리드키(ReadKey) at fortnightly against SLS's every 8 months. SLS's advantage is iOS requirement (12.0 vs 16.6). 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.

SLS ships an update every 8 months, 리드키(ReadKey) fortnightly. Both last shipped on October 7, 2026.

## The numbers

| Metric | SLS | 리드키(ReadKey) |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 33.3% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 8 months | **Fortnightly** |
| Monetization | Free | — |
| Size | 13 MB | 66 MB |
| Requires iOS | **12.0** | 16.6 |
| Devices | iPhone, iPod | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [IAP EDU](https://appshunter.io/developer/1545801777) | [Goodwillhunting, Inc](https://appshunter.io/developer/1061875607) |

## What reviewers say

### SLS

[App page](https://appshunter.io/ios/app/sls/id1545901734)

This is a smart application for Korean language learning, developed by IAP EDU. It offers an educational experience focused on mastering the Korean language.

**Highlights:** Korean language learning, Smart application, Educational content, Developed by IAP EDU

**Features:** macOS Compatibility

**In-app purchases:** none


### 리드키(ReadKey)

[App page](https://appshunter.io/ios/app/readkey/id6748025836)

**In-app purchases:** none


## Frequently asked questions

### Is SLS free?

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

### Is 리드키(ReadKey) free?

리드키(ReadKey) is free to download, with no in-app purchases.

### Do SLS or 리드키(ReadKey) have ads?

Neither SLS nor 리드키(ReadKey) shows ads.

### Which is updated more often, SLS or 리드키(ReadKey)?

SLS ships an update every 8 months, and 리드키(ReadKey) fortnightly. Most recently, SLS was updated on October 7, 2026 and 리드키(ReadKey) on October 7, 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.*