# Stack Testers Friend vs Aliver

The clearest difference is review sentiment: Stack Testers Friend at 100% against Aliver's 22%. Stack Testers Friend also leads on in-app purchases (none vs 6) and ads (none vs shown). Aliver's advantage is update cadence (monthly vs every 7 months). On price there is nothing between them.

Both are free to download. Aliver sells 6 in-app purchases, starting at $5.99 per 7 days. Stack Testers Friend asks for nothing beyond the download.

Stack Testers Friend ships an update every 7 months, Aliver monthly. The most recent releases landed on September 24, 2026 and October 12, 2026 respectively.

## The numbers

| Metric | Stack Testers Friend | Aliver |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.8 (1.4K ratings)](https://appshunter.io/ios/app/aliver-screen-time-control/id6741529047/reviews)** |
| Number of ratings | — | **1.4K** |
| Positive reviews | **100.0% of reviews** | 21.7% of reviews |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 7 months | **Monthly** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 33 MB | 44 MB |
| Requires iOS | **13.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Lewis Holmes](https://appshunter.io/developer/1454834389) | [Reface Europe UAB](https://appshunter.io/developer/1679743976) |

## What reviewers say

### Stack Testers Friend

[App page](https://appshunter.io/ios/app/stack-testers-friend/id1454834390)

This mobile toolkit provides essential on-site calculations for stack testers. Quickly perform gas conversions, probe position calculations, and other vital engineering tasks without needing a laptop. It's designed for environmental engineers needing immediate access to data while working in the field.

**Highlights:** Gas conversion calculations, Isokinetic sample position calculations, Extraction rate calculations, Gas density calculations, Particulate matter normalization, Calibration function calculations

**Features:** macOS Compatibility

**In-app purchases:** none


### Aliver

[App page](https://appshunter.io/ios/app/aliver-screen-time-control/id6741529047)

This app helps you reduce screen time and build healthier digital habits without deleting your favorite applications. It offers features like app blocking, screen time tracking, and daily routines to help you focus, reduce stress, and improve sleep.

**Highlights:** Reduce screen time, App blocking, Screen time tracking, Build mindful habits, Daily routines, Focus deeper

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

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Aliver PRO | $5.99 | per 7 days |
| Aliver PRO | $8.99 | per 7 days |
| Aliver PRO | $14.99 | per month |
| Aliver PRO | $44.99 | per year |
| Aliver PRO | $59.99 | per year |
| Aliver PRO | $69.99 | per year |

**What reviewers like**

- 👍 Helpful app
- 👍 Helped build muscle

**What reviewers complain about**

- 💰 Forced to pay money
- 💰 Unnecessary billing
- 💰 Paywall
- 💰 You have to pay for the pro version

**Reported bugs**

- Couldn't get past pay wall
- Couldn't even get into the app
- Paywall issues

**Requested features**

- Make an app more people can use without paying


## Frequently asked questions

### Is Stack Testers Friend free?

Stack Testers Friend is free to download, with no in-app purchases.

### Is Aliver free?

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

### Do Stack Testers Friend or Aliver have ads?

Aliver shows ads; Stack Testers Friend does not.

### Which is updated more often, Stack Testers Friend or Aliver?

Stack Testers Friend ships an update every 7 months, and Aliver monthly. Most recently, Stack Testers Friend was updated on September 24, 2026 and Aliver on October 12, 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.*