App Overview

Auto Fills Drum Fill Generator icon

Auto Fills Drum Fill Generator

Cem Olcay · Music

Auto Fills is a random MIDI generator app for creating drum fills for your drum synth apps or hardware synthesizers

$5.99 · In-app purchases

PRICE
$5.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.6
18 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 included17 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 Auto Fills Drum Fill Generator: 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

Expand the library of drum patterns and styles.

Assumption to check: Limited pattern options can frustrate users.

Validate with people who use this workflow before building.

Hypothesis 2

Simplify navigation and provide tutorials.

Assumption to check: Users may find the interface overwhelming.

Validate with people who use this workflow before building.

Hypothesis 3

Integrate sharing options for generated fills.

Assumption to check: Lack of social sharing features.

Validate with people who use this workflow before building.

Hypothesis 4

Enhance audio processing for better performance.

Assumption to check: Audio playback quality may vary.

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

Auto Fills is a random MIDI generator app for creating drum fills for your drum synth apps or hardware synthesizers. It works as an Audio Unit AUv3 plugin with the supported host apps such as AUM, Loopy Pro, Logic Pro, Cubasis, Nanostudio, apeMatrix etc. In Auto Fills, you are working with a drum kit. You can either create the kit by adding drum parts and assigning them MIDI notes/channels yourself, or you can select a kit templete from the settings menu for an app or hardware for quick setup. - In Kit mode, you can assign a probability value to each drum part. - In Velocity mode, you can assign a velocity to each drum part, and you can also introduce velocity variety for them. - In Duration mode, you can set the drum fill length as well as the waiting time before and/or after the drum fill, in beats or bars. - If you've set "wait before the fill" and/or "wait after the fill" durations in the Duration mode, the drum fill won't be played during the waiting periods. If you have a favorite drum sequencer, you can route it through the Auto Fills, before the drum app, like - Drum sequencer -> Auto Fills -> Drum App And you can block the incoming MIDI from the drum sequencer during the drum fill. You enable the option in the Duration mode by toggling "block incoming MIDI during the fill" option. You also have an option for randomizing the drum fill on every cycle. Assigning probability values is crucial in the Kit mode. If you want to hear a specific drum part mode, just increase it's probability. If you would like to hear a drum part less ofter, just decrease its probability. If you set a probability to zero, it won't play in the drum fill. - Density knob leaves out notes from the drum if you decrease its value. It introduces rests in the drum fill without regenerating the fill. - Voices knob sets the maximum number of drum parts can be played at the same time (polyphony). The algorithm chooses a value between 1 and the maximum voice count randomly on every step of the drum fill. - Rate note sets the speed of the drum fill. - Generate button lets you regenerate the drum fill. Changing the kit by adding/removing parts, probabilities and voice count also regenerates the fill automatically. Auto Fills is a MIDI app and it does not produce it's own sound. You need to route Auto Fills MIDI out to an audio app's MIDI input in order to hear the voice.

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-sound
React Navigation
TypeScript
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.