# 氢刻 vs Nebula Sound

The clearest difference is update cadence: Nebula Sound at weekly against 氢刻's every 3 weeks. 氢刻's advantage is device support (3 vs 1) and iOS requirement (15.0 vs 17.0). On price, ads and in-app purchases there is nothing between them.

Both are free to download. 氢刻 sells 8 one-off in-app purchases and Nebula Sound sells 4 in-app purchases, starting at $9.99 per month. Whichever you choose, the download price is not the number that matters.

氢刻 ships an update every 3 weeks, Nebula Sound weekly. The most recent releases landed on November 7, 2026 and November 10, 2026 respectively.

## The numbers

| Metric | 氢刻 | Nebula Sound |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (5 ratings)](https://appshunter.io/ios/app/ai/id1585104628/reviews)** | — |
| Number of ratings | **5** | — |
| Positive reviews | 83.3% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Weekly** |
| Monetization | Free | — |
| Size | 20 MB | 13 MB |
| Requires iOS | **15.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [QingKe Tech Co., Ltd.](https://appshunter.io/developer/1584950202) | [NEBULA DATA SERVICE PTE. LTD.](https://appshunter.io/developer/6802600348) |

## What reviewers say

### 氢刻

[App page](https://appshunter.io/ios/app/ai/id1585104628)

This app helps you capture, organize, and recall information through a structured card system. It utilizes AI to extract key points and generate study materials like flashcards and quizzes. Share and access learning resources within a community to enhance your knowledge retention and thinking.

**Highlights:** Card-based note-taking, AI-powered key point extraction, Intelligent review and recall (Anki-style), Flashcard and quiz generation, Community sharing of card sets, Import notes from WeChat Read, Scientific statistics and progress tracking

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

**In-app purchases (8)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VIP of one month | $1.99 | one-time |
| 氢刻专业版-1个月 | $2.99 | one-time |
| VIP of one year | $12.99 | one-time |
| 氢刻专业版-1年 | $19.99 | one-time |
| VIP of three years | $29.99 | one-time |
| 氢刻专业版-3年 | $39.99 | one-time |
| Premium Lifetime | $69.99 | one-time |
| Pro Lifetime | $89.99 | one-time |


### Nebula Sound

[App page](https://appshunter.io/ios/app/nebula-sound/id6802600345)

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| GE Basic | $9.99 | per month |
| Basic | $14.99 | per month |
| GE PLUS | $19.99 | per month |
| PLUS | $29.99 | per month |


## Frequently asked questions

### Is 氢刻 free?

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

### Is Nebula Sound free?

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

### Do 氢刻 or Nebula Sound have ads?

Neither 氢刻 nor Nebula Sound shows ads.

### Which is updated more often, 氢刻 or Nebula Sound?

氢刻 ships an update every 3 weeks, and Nebula Sound weekly. Most recently, 氢刻 was updated on November 7, 2026 and Nebula Sound on November 10, 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.*