# Prompt Engineering Library vs Crisp Scan

The clearest difference is price: Crisp Scan at Free against Prompt Engineering Library's $0.99. Crisp Scan also leads on update cadence (every 9 days vs every 3 weeks). Prompt Engineering Library's advantage is in-app purchases (none vs 1) and iOS requirement (15.1 vs 17.0). On ads and device support there is nothing between them.

Crisp Scan is free to download; Prompt Engineering Library costs $0.99 up front. Crisp Scan sells 1 one-off in-app purchase. Prompt Engineering Library asks for nothing beyond the download.

Prompt Engineering Library ships an update every 3 weeks, Crisp Scan every 9 days. The most recent releases landed on September 13, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | Prompt Engineering Library | Crisp Scan |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 9 days** |
| Size | 30 MB | 1 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Ruud Telman](https://appshunter.io/developer/1843436085) | [Vikram Joshi](https://appshunter.io/developer/1875452225) |

## What reviewers say

### Prompt Engineering Library

[App page](https://appshunter.io/ios/app/prompt-engineering-library/id6753958156)

**In-app purchases:** none


### Crisp Scan

[App page](https://appshunter.io/ios/app/crisp-scan/id6771958752)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Crisp Pro | $4.99 | one-time |


## Frequently asked questions

### Is Prompt Engineering Library free?

Prompt Engineering Library costs $0.99, with no in-app purchases.

### Is Crisp Scan free?

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

### Do Prompt Engineering Library or Crisp Scan have ads?

Neither Prompt Engineering Library nor Crisp Scan shows ads.

### Which is updated more often, Prompt Engineering Library or Crisp Scan?

Prompt Engineering Library ships an update every 3 weeks, and Crisp Scan every 9 days. Most recently, Prompt Engineering Library was updated on September 13, 2026 and Crisp Scan on October 9, 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.*