App Overview

BeatMirror: Track BPM icon

BeatMirror: Track BPM

Ten Kettles Inc. · Music

BeatMirror uses your device's built-in microphone to detect musical tempo in real-time

$6.99 · In-app purchases

PRICE
$6.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.7
253 ratings · Top 15%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

Build your own version

Build Kit

Make this idea yours

A product spec, screen plans, and build steps for your coding agent.

First kit free with a verified email

Add to a Remix

Combine features and design from your favorite apps.

Kit ready. Verify your email to download it.

What's included18 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
Preview a sample Build Kit No email needed

Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

JavaScript is required to complete mailbox verification.

Free quick prompt For a smaller starting point

Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for BeatMirror: Track BPM: map the core Music workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

Preview ready. Verify your email to reveal and copy the full prompt.

JavaScript is required to complete mailbox verification. Return to this prompt preview.

Continue in Rork copies the full prompt to your clipboard first, then opens Rork in a new tab.

Continue in Rork >

Affiliate link: CloneChart may earn a commission at no extra cost

Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Implement advanced algorithms for more accurate BPM detection.

Assumption to check: Users report inaccuracies in BPM tracking.

Validate with people who use this workflow before building.

Hypothesis 2

Enhance playback options and detailed history tracking.

Assumption to check: Limited history and playback features.

Validate with people who use this workflow before building.

Hypothesis 3

Allow users to track BPM without internet connectivity.

Assumption to check: No offline functionality.

Validate with people who use this workflow before building.

Hypothesis 4

Offer transparent pricing models and free trials.

Assumption to check: Subscription model can be unclear.

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

BeatMirror uses your device's built-in microphone to detect musical tempo in real-time. Just tap start and a graph of your tempo will appear right away, allowing you to scroll through your tempo history and see trends. Perfect for musicians looking to build their internal rhythm, or to see the tempo of their favorite songs in real-time! TESTIMONIALS: "BeatMirror truly is simplicity at its finest. That quality is missing from most apps who try to cram too many features into one app thus making it difficult to use and many times buggy. We feel like your app is VERY good. We're reviewing BeatMirror and it will be a part of the next show. It's got nothing but thumbs up!" - Phil Smith of "Drummer's Weekly Groovecast" (podcast) "When I first heard about BeatMirror, I was kind of skeptical but after trying it out for weeks now and playing with it everyday, I'm mindblown. Alex really wanted to put a focus on helping drummers improve their internal clock and I really think he's done so." - Richard Ducat of "Drummers I Like" (podcast) "Overall, this app is so quick and simple to use, there's not really an excuse as to why you wouldn't use it during practice sessions, just to see how you’re improving. If you're a drummer, having an app on your phone or tablet like BeatMirror just makes sense." - Laura Barnes of MI-PRO (mi-pro.co.uk) FEATURES: Good music needs good rhythm. But learning to stay on beat—learning to groove—isn't always easy. Build your inner metronome with BeatMirror and catch yourself when you're speeding up or slowing down. Here’s what BeatMirror has to offer: - Wide tempo range. Tempo detection between 35 bpm and 220 bpm. - Fast. Detects tempo quickly and accurately. - Flexible. Accurate across time signatures (e.g., 4/4, 6/8) and rhythm styles (e.g., swing). - Real-time, scrollable graph. Displays current tempo and tempo history in real-time. - Zoom features. Choose tight, loose, or full zoom—or double-tap the graph for easy toggling. - Easy sharing. Share your tempo graph with a tap. - Easy-to-read interface. Optimized for various light environments, such as stages and practice spaces. - Tempo keyboard. A special tempo keyboard (with tap pad) lets you set a target tempo easily and intuitively. - Visual feedback. If you drift from your target tempo, BeatMirror shows a red (slow down!), blue (speed up!), or green (perfect!) indicator. - Custom count-in. BeatMirror gives you an optional count-in before you start playing. - Versatile. Perfect for solo practice, band rehearsals, recorded music, and you can even use it at concerts! - Triplet mode. Boost accuracy in triplet-time with the new triplet mode. - Tutorial. An in-app tutorial gets you up and running in a flash. TIPS FOR BEST PERFORMANCE: - Avoid handling your device during tempo measurement. - Be mindful of competing noise near the device's microphone (e.g., conversation, typing). NOTES ON USAGE: - Recorded music. To detect the tempo of recorded music using BeatMirror, follow these steps: 1) Play a song from your favorite music player app using the device speaker (i.e., unplug your headphones). Or, play the song from a different device altogether. 2) Open BeatMirror and start tempo detection, adjusting the tempo range if needed. 3) The song's precise tempo will then be displayed in real-time. Questions or feedback about BeatMirror? Please don't hesitate to get in touch anytime. Just tap the envelope icon in BeatMirror or reach out at tenkettles.com/contact. Happy practicing! -Alex

Written user reviews are not shown here. Check current App Store reviews >

Screenshots

< Scroll to see more >

Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

SUGGESTED BUILD STACK
React Native
Expo
Zustand
expo-av
react-native-animated
react-navigation
BUILD KIT DIFFICULTY
Advanced

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.