GridInstrument vs Midi Poly Grid
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
GridInstrument
This app transforms your iOS device into a unique musical instrument with a grid-based interface. Explore over 20 musical modes and various grid layouts. It also supports external MIDI controllers like the Launchpad for expanded creative possibilities.
- Grid-based note arrangement
- Launchpad integration
- Over 20 musical modes
- Multiple grid layouts
- Core MIDI out
- Audiobus 3 MIDI support
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GridInstrument lets you play your iOS device like a musical instrument. Instead of a piano keyboard, notes are arranged on a grid. It also lets you hook up your Launchpad device (using the Apple Camera Connection Kit) and play that as well! Features: - Launchpad integration (connect your Launchpad Mini in low-power mode without a hub or any other Launchpad with a powered hub) - Change octaves - Change keys - Change from over 20 musical modes ("Major, Minor, Dorian, Mixolydian, etc.") - Choose between three grid layouts ("Diatonic", "Chromatic/4ths String Layout", "Drum rack"), as well as row note offset/overlap setting - Core MIDI out so that you use GridInstrument to control your other instruments - Audiobus 3 MIDI support - MIDI note input so that you can see notes triggered by other devices on your grid Want to see some other feature implemented? Contact us at the Decidedly website.
Midi Poly Grid
This app functions solely as a MIDI controller, requiring a host application or DAW to produce sound. It offers intuitive pad controls for melodies and finger drumming, with advanced modulation options like MPE and polyphonic aftertouch. Connect virtually or via USB/Bluetooth to other devices and DAWs.
- Size-adjustable grid of pads
- MPE and polyphonic aftertouch modulation
- Custom grid creation
- Virtual MIDI connection
- Preset saving
- Multiple layouts and colors
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# Midi Poly Grid This App is Open Source. Access the code here: https://github.com/anzbert/beat_pads ## Important Disclaimer This App is **ONLY** usable as a Midi Controller. It does **NOT** produce any sound on its own and requires a host application or a second device with a DAW or other sound production app. ## Information Midi Poly Grid is a lightweight Midi Controller app for mobile phones and tablets for melodies and finger drumming at home and on the go. Connections can be made virtually to other apps via platform midi channels, or via USB or Bluetooth Midi to other devices. This app aims to be an easy-to-use pad input device featuring a variety of layouts, intuitive playability and modern modulation options, such as MPE and Polyphonic Aftertouch. It was designed for people that prefer pads to pianos! The focus of this app is not to be a jack-of-all-trades Midi swiss army knife, but instead to be a great at one thing: Intuitive and versatile pad controls. ## Features - A size-adjustable grid of pads for finger drumming and melody input - Various layouts and colors, inspired by the Ableton Push - Presets can be saved with different pad setups - Innovative MPE and polyphonic Aftertouch modulation with graphical feedback - Push Style MPE pitchbend and slide - Send Velocity by Y position on pad, randomly or with a fixed value - Usable as a standard MIDI device with any PC, Mac or other USB or Bluetooth device - Optional controls, such as Pitch Bend, Mod Wheel and Sustain - Highligh a large number of musical scales - Receives Midi Notes, making the pads usable like a Launchpad - Custom grid creation based on the note intervals on the X and Y Axis to create Grids inspired by the Harmonic Table, Wicki Hayden, MidiMech and others - Supports virtual Midi connection to other apps on your device - Built-In support for the popular finger drumming courses from XpressPads.com - And more... ## Feedback and Contributions Anyone is most welcome to contribute, report an issue or start a discussion in the Github repository. Thanks! ## Licence Licenced under GPL3. The code in this project is freely usable in any other open source project. Enjoy! ## iOS Specific Information Can be used with any Mac via USB, Bluetooth Midi or WiFi. Usage with PC is limited to WiFi with free third-party software (rtpMidi), and USB with third-party USB midi connectors, due to Apple's limited implementation of USB Midi on iOS. AUv3 is unfortunately not supported at this time, as it is currently impossible with Flutter. More info about that here: https://github.com/flutter/flutter/issues/16092
Screenshots
Verdict
The clearest difference is rating: Midi Poly Grid at 5.0 against GridInstrument's 4.5. Midi Poly Grid also leads on review sentiment (100% vs 83%). GridInstrument's advantage is iOS requirement (8.0 vs 15.0). On price, ratings volume, update cadence 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
GridInstrument costs $3.99 and Midi Poly Grid $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Midi Poly Grid holds the better App Store score, 5.0 against 4.5. Both are backed by a comparable volume of ratings — 11 and 8 respectively. Written reviews point the same way: 83% of GridInstrument's written reviews are positive against 100% of Midi Poly Grid's.
GridInstrument ships an update weekly, Midi Poly Grid every 11 days. The most recent releases landed on September 11, 2026 and September 27, 2026 respectively.
| Parameter | GridInstrument | Midi Poly Grid |
|---|---|---|
| Price | $3.99 | $3.99 |
| Rating | 4.5 (11 ratings) | 5.0 (8 ratings) — better |
| Positive reviews | 83.3% of reviews | 100.0% of reviews — better |
| Number of ratings | 11 — better | 8 |
| Update frequency | Weekly — better | Every 11 days |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 8.0 — better | 15.0 |
| Further details — not scored | ||
| Size | 15 MB | 24 MB |
| Age rating | 4+ | 4+ |
| Developer | Decidedly, LLC | Andreas Mueller |
Customer experience
GridInstrument
Midi Poly Grid
In-app purchases
GridInstrument
No in-app purchases
Midi Poly Grid
No in-app purchases









