Comparison

FlexLft vs Reaction Lab

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

FlexLft

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
Read full description

Transform your strength training with FlexLift - the simple yet powerful app for creating and tracking custom weight training programs. Perfect for Intermediate Lifters Whether you're following 5/3/1, StrongLifts, or your own custom program, FlexLift gives you the flexibility to build exactly what you need. No more being locked into rigid, one-size-fits-all workout plans. Core Features • Custom Program Builder - Create unlimited workout programs with your preferred exercises, sets, reps, and weights • Smart Progression - Automatic weight suggestions based on your performance to keep you progressing • Built-in Rest Timer - Stay focused with customizable rest periods between sets • Apple Health Integration - All your workouts automatically sync to Apple Health • Workout History - Track your progress and see how you've improved over time • Offline First - No internet required - your data stays on your device How It Works 1. Create your custom program with exercises, sets, reps, and starting weights 2. Start your workout and log each set as you complete it 3. Progress with smart weight suggestions for your next workout 4. Track your improvement over time with detailed workout history What Makes FlexLift Different • Truly Customizable - Build any program structure you want (A/B splits, full body, push/pull/legs, etc.) • Simple Interface - Clean, distraction-free design focused on getting your workout done • Smart Progression - Intelligent weight suggestions help you progress safely and effectively • Apple Health Ready - Seamless integration with your existing health ecosystem Perfect For • Intermediate lifters (6+ months experience) who want more flexibility • Anyone tired of being locked into rigid program structures • Lifters who want to track progression across custom programs • Users who prefer simple, focused workout apps Privacy First Your workout data stays on your device. We don't collect personal information or track your usage. Only sync to Apple Health with your explicit permission. Requirements • iOS 15.0 or later • iPhone (portrait mode optimized) • Apple Health integration (optional) Ready to take control of your strength training? Download FlexLift and build the program that works for you.

About

Reaction Lab

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
Read full description

Reaction Lab is a fast, accurate reaction-time testing suite built to help you measure and understand how quickly you respond in different situations. Whether you’re training for sports, improving focus, or tracking performance over time, Reaction Lab gives you clean, scientifically-inspired tests and easy-to-read analytics—right on your iPhone. Test Your Reaction Time in Multiple Ways Reaction time isn’t just one thing. Reaction Lab includes multiple test types designed to measure different pathways and skills: • Simple Visual Tap – Tap as soon as a visual stimulus appears • Choice Reaction – Respond to directional or on-screen prompts with speed and accuracy • Audio Reaction – React to sound cues for “eyes-off” testing • Haptic Reaction – React to vibration cues with no visuals or audio • Grip-Release (Inhibitory Control) – Hold, then release as fast as possible when prompted • Motion Reaction – React by moving the phone (tilt/lift/rotate) • Dual-Task Under Load – React while performing a secondary task to measure real-world performance • Fatigue Drift – Track how reaction time changes over a continuous timed session • Anticipation vs Reaction – Detect premature responses and impulse control patterns • Asymmetry Testing – Compare dominant vs non-dominant performance Track Progress Over Time Reaction Lab automatically saves your sessions and turns raw reaction data into meaningful insights: • Session summaries: median, average, best, worst, variability • Accuracy metrics: false starts, errors, timeouts • Trend charts by test type over 7 / 30 / 90 days • Per-session breakdowns across every trial Clean, Focused, Tool-Like Design Reaction Lab is built to be simple, fast, and distraction-free: • Large touch targets and high-contrast test screens • Clear trial progress indicators • Instant feedback on mistakes or false starts • Smooth navigation between tests, history, insights, and settings Fully On-Device and Private Your data stays on your device. • No accounts • No cloud sync required • No tracking • Works offline If you’ve ever wondered how your reaction time changes with training, fatigue, stress, or consistency—Reaction Lab gives you the tools to measure it. Download Reaction Lab and start testing. Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://anthonyharveyapps.com/privacy-policy-reaction-lab

Screenshots

FlexLft4 screens
Reaction Lab4 screens

Verdict

The call

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.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

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.

ReceptionRating · Positive reviews · Number of ratings

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.

UpkeepUpdate frequency

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.

Scorecard3 real differences · 7 level
FlexLft versus Reaction Lab: the parameters behind the verdict, then further details
ParameterFlexLftReaction Lab
PriceFreeFree
Rating5.0 (2 ratings)5.0 (2 ratings)
Positive reviews100.0% of reviews—
Number of ratings22
Update frequencyEvery 2 months — betterEvery 7 months
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhoneiPhone
Requires iOS17.6 — better18.0
Further details — not scored
Size6 MB22 MB
Age rating4+4+
DeveloperJoshua ColvinAnthony Harvey

Customer experience

FlexLft

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Reaction Lab

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

FlexLft

No in-app purchases

2 purchases

Reaction Lab

Subscriptions2
  • React Fast Monthly3 Days trial$1.991 Month
  • React Fast Yearly3 Days trial$4.991 Year

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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