# MindKoi vs API Inspector Cert Prep

The clearest difference is update cadence: MindKoi at every 10 days against API Inspector Cert Prep's every 3 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. MindKoi sells 2 in-app purchases, starting at $9.99 per month and API Inspector Cert Prep sells 3 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

MindKoi ships an update every 10 days, API Inspector Cert Prep every 3 months. The most recent releases landed on September 21, 2026 and October 2, 2026 respectively.

## The numbers

| Metric | MindKoi | API Inspector Cert Prep |
| --- | --- | --- |
| Price | Free | Free |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 10 days** | Every 3 months |
| Size | 18 MB | 32 MB |
| Requires iOS | 16.0 | **15.1** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Pavel Kazlou](https://appshunter.io/developer/1462519810) | [Simon Shih](https://appshunter.io/developer/1870707682) |

## What reviewers say

### MindKoi

[App page](https://appshunter.io/ios/app/mindkoi-study-smarter-and-learn/id6751173393)

**Features:** macOS Compatibility

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Plus | $9.99 | per month |
| Annual Plus | $59.99 | per year |


### API Inspector Cert Prep

[App page](https://appshunter.io/ios/app/api-inspector-cert-prep/id6785875538)

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| API 510 – Pressure Vessel Inspector | $19.99 | one-time |
| API 570 – Piping Inspector | $19.99 | one-time |
| API 653 – Storage Tank Inspector | $19.99 | one-time |


## Frequently asked questions

### Is MindKoi free?

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

### Is API Inspector Cert Prep free?

API Inspector Cert Prep is free to download, with in-app purchases available.

### Do MindKoi or API Inspector Cert Prep have ads?

Neither MindKoi nor API Inspector Cert Prep shows ads.

### Which is updated more often, MindKoi or API Inspector Cert Prep?

MindKoi ships an update every 10 days, and API Inspector Cert Prep every 3 months. Most recently, MindKoi was updated on September 21, 2026 and API Inspector Cert Prep on October 2, 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.*