# ReactionFlash vs Chemistry By Design

The clearest difference is update cadence: ReactionFlash at every 4 months against Chemistry By Design's every 16 months. ReactionFlash also leads on ratings volume (42 vs 14). Chemistry By Design's advantage is rating (5.0 vs 4.8) and iOS requirement (6.0 vs 14.0). On price, review sentiment, 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.

Chemistry By Design holds the better App Store score, 5.0 against 4.8. Both are backed by a comparable volume of ratings — 42 and 14 respectively. Written reviews split almost evenly too, at 81% and 81% positive.

ReactionFlash ships an update every 4 months, Chemistry By Design every 16 months. The most recent releases landed on November 1, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | ReactionFlash | Chemistry By Design |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (42 ratings)](https://appshunter.io/ios/app/reactionflash/id432080813/reviews) | **[5.0 (14 ratings)](https://appshunter.io/ios/app/chemistry-by-design-target-synthesis-database/id451791347/reviews)** |
| Number of ratings | **42** | 14 |
| Positive reviews | 80.6% of reviews | **80.8% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 4 months** | Every 16 months |
| Monetization | Free | Free |
| Size | 37 MB | 23 MB |
| Requires iOS | 14.0 | **6.0** |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Elsevier Limited](https://appshunter.io/developer/1437273934) | [University of Arizona](https://appshunter.io/developer/437682109) |

## What reviewers say

### ReactionFlash

[App page](https://appshunter.io/ios/app/reactionflash/id432080813)

This app serves as a comprehensive flashcard-style learning tool for named chemical reactions. It provides detailed information on reaction mechanisms and examples from scientific literature, with a quiz mode to test user knowledge.

**Highlights:** Learn named chemical reactions, Understand reaction mechanisms, View literature examples, Quiz mode for knowledge testing, Flashcard interface

**Features:** macOS Compatibility

**In-app purchases:** none


### Chemistry By Design

[App page](https://appshunter.io/ios/app/chemistry-by-design-target-synthesis-database/id451791347)

This interactive virtual flashcard app helps students practice chemistry synthesis skills. It displays reagents, starting materials, and products for each step in constructing natural products or pharmaceuticals. Various browsing options are available for self-testing.

**Highlights:** Interactive virtual flashcards, Practice synthetic sequences, Display reagents, starting materials, and products, Natural product and pharmaceutical synthesis, Multiple browsing options for testing

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is ReactionFlash free?

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

### Is Chemistry By Design free?

Chemistry By Design is free to download, with no in-app purchases.

### Which has better reviews, ReactionFlash or Chemistry By Design?

Chemistry By Design is rated higher. ReactionFlash averages 4.8 out of 5 from 42 ratings, while Chemistry By Design averages 5.0 from 14 ratings.

### Do ReactionFlash or Chemistry By Design have ads?

Neither ReactionFlash nor Chemistry By Design shows ads.

### Which is updated more often, ReactionFlash or Chemistry By Design?

ReactionFlash ships an update every 4 months, and Chemistry By Design every 16 months. Most recently, ReactionFlash was updated on November 1, 2026 and Chemistry By Design on November 4, 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.*