# FlexLft vs Reaction Lab

The clearest difference is in-app purchases: FlexLft at none against Reaction Lab's 2. FlexLft also leads on update cadence (every 2 months vs every 7 months). On price, rating, ratings volume and ads there is nothing between them.

Both are free to download. Reaction Lab sells 2 in-app purchases, starting at $1.99 per month. FlexLft asks for nothing beyond the download.

On the App Store both sit at effectively the same score — 5.0 for FlexLft against 5.0 for Reaction Lab. Both are backed by a comparable volume of ratings — 2 and 2 respectively.

FlexLft ships an update every 2 months, Reaction Lab every 7 months. The most recent releases landed on October 7, 2026 and September 26, 2026 respectively.

## The numbers

| Metric | FlexLft | Reaction Lab |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (2 ratings)](https://appshunter.io/ios/app/flexlft/id6753325612/reviews) | [5.0 (2 ratings)](https://appshunter.io/ios/app/reaction-lab-reflex-tests/id6757831974/reviews) |
| Number of ratings | 2 | 2 |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 7 months |
| Monetization | **Free** | Free with in-app purchases |
| Size | 6 MB | 22 MB |
| Requires iOS | **17.6** | 18.0 |
| Devices | iPhone | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Joshua Colvin](https://appshunter.io/developer/1843515001) | [Anthony Harvey](https://appshunter.io/developer/1478197285) |

## What reviewers say

### FlexLft

[App page](https://appshunter.io/ios/app/flexlft/id6753325612)

Create and track custom weight training programs with this app. It offers smart progression suggestions, a built-in rest timer, and syncs with Apple Health. Your data stays private and on your device.

**Highlights:** Custom program builder, Smart weight progression, Built-in rest timer, Apple Health integration, Workout history tracking, Offline functionality

**Features:** macOS Compatibility

**In-app purchases:** none


### Reaction Lab

[App page](https://appshunter.io/ios/app/reaction-lab-reflex-tests/id6757831974)

Measure and improve your response speed with a suite of scientifically-inspired tests. Track progress over time with detailed analytics and gain insights into your performance in various situations. Designed for focus and privacy, all data stays on your device.

**Highlights:** Multiple reaction time test types, Visual, audio, and haptic cues, Grip-release and motion-based tests, Dual-task and fatigue tracking, Detailed session summaries and trend charts, On-device data privacy, Offline functionality

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| React Fast Monthly | $1.99 | per month |
| React Fast Yearly | $4.99 | per year |


## Frequently asked questions

### Is FlexLft free?

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

### Is Reaction Lab free?

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

### Which has better reviews, FlexLft or Reaction Lab?

FlexLft and Reaction Lab are both rated 5.0 out of 5 on the App Store, from 2 and 2 ratings respectively.

### Do FlexLft or Reaction Lab have ads?

Neither FlexLft nor Reaction Lab shows ads.

### Which is updated more often, FlexLft or Reaction Lab?

FlexLft ships an update every 2 months, and Reaction Lab every 7 months. Most recently, FlexLft was updated on October 7, 2026 and Reaction Lab on September 26, 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.*