# StepPolyArp vs Atom | Piano Roll 2

The clearest difference is in-app purchases: Atom | Piano Roll 2 at none against StepPolyArp's 2. Atom | Piano Roll 2 also leads on update cadence (weekly vs every 2 months) and iOS requirement (12.1 vs 15.0). StepPolyArp's advantage is rating (4.8 vs 4.5) and review sentiment (87% vs 68%). On price, ratings volume, ads and monetization model there is nothing between them.

StepPolyArp costs $19.99 and Atom | Piano Roll 2 $19.99 up front. StepPolyArp sells 2 one-off in-app purchases. Atom | Piano Roll 2 asks for nothing beyond the download.

StepPolyArp holds the better App Store score, 4.8 against 4.5. Both are backed by a comparable volume of ratings — 48 and 96 respectively. Written reviews point the same way: 87% of StepPolyArp's written reviews are positive against 68% of Atom | Piano Roll 2's.

StepPolyArp ships an update every 2 months, Atom | Piano Roll 2 weekly. Both last shipped on October 19, 2026.

## The numbers

| Metric | StepPolyArp | Atom | Piano Roll 2 |
| --- | --- | --- |
| Price | $19.99 | $19.99 |
| Rating | **[4.8 (48 ratings)](https://appshunter.io/ios/app/steppolyarp/id1361313588/reviews)** | [4.5 (96 ratings)](https://appshunter.io/ios/app/atom-piano-roll-2/id1536259776/reviews) |
| Number of ratings | 48 | **96** |
| Positive reviews | **87.0% of reviews** | 67.5% of reviews |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 months | **Weekly** |
| Monetization | Paid | Paid |
| Size | 38 MB | 16 MB |
| Requires iOS | 15.0 | **12.1** |
| Devices | **iPhone, iPad, iPod, Mac** | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Laurent Colson](https://appshunter.io/developer/381525765) | [Victor Porof](https://appshunter.io/developer/1446209018) |

## What reviewers say

### StepPolyArp

[App page](https://appshunter.io/ios/app/steppolyarp/id1361313588)

This app functions as a real-time polyphonic and polyrhythmic MIDI step arpeggiator and sequencer. It can generate melodic patterns from input or operate as a standalone sequencer. Save and sync unlimited presets with iCloud, featuring extensive customization for patterns and step controllers.

**Highlights:** Standalone app and AUv3 MIDI effect plugin, Arpeggiator and step sequencer modes, Programmable step matrix with transposition lines, Polyrhythmic step controllers, Internal sound bank, Ableton Link and MIDI sync support, Unlimited preset saving with iCloud sync

**Features:** Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Dance Horizons | $4.99 | one-time |
| Analog Sequence | $4.99 | one-time |


### Atom | Piano Roll 2

[App page](https://appshunter.io/ios/app/atom-piano-roll-2/id1536259776)

This advanced AUv3 MIDI editor and sequencer allows for complex musical composition and live performance. It functions as a plugin within compatible music hosts, enabling users to create intricate patterns, launch clips, and customize workflows with scripting.

**Highlights:** AUv3 MIDI note editor, Modular sequencer, Clip launcher, Step input and real-time recording, Customizable layouts and themes, Scripting for custom workflows, Ghost lanes for harmonies and counterpoint

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

**In-app purchases:** none

**What reviewers like**

- 🎹 Excellent piano roll editor with intuitive interface
- 🎯 Powerful MIDI sequencing and clip launching capabilities
- 🔗 Great integration with AUM and hardware controllers like Launchpad
- ✨ Feature-rich with multiple layers, patterns, and flexible grid
- ⚡ Smooth and responsive performance

**What reviewers complain about**

- 🐛 Frequent crashes and stability issues in AUM
- 🖱️ No mouse/trackpad support for drawing notes
- 📝 Missing MIDI CC editing functionality
- 🎚️ Poor velocity editing workflow
- 👁️ UI elements too small and cramped

**Reported bugs**

- Crashes when saving sessions in AUM
- Notes get corrupted during playback
- White background display issue
- Position indicator jumps when loop doesn't start at bar 1
- Buttons for adding bars disappear after certain point

**Requested features**

- MIDI CC editing and visualization
- Mouse and trackpad input support
- Logic Pro for iPad support
- Chord entry in step input mode
- Velocity editing improvements and visual feedback


## Frequently asked questions

### Is StepPolyArp free?

StepPolyArp costs $19.99, and also offers in-app purchases.

### Is Atom | Piano Roll 2 free?

Atom | Piano Roll 2 costs $19.99, with no in-app purchases.

### Which has better reviews, StepPolyArp or Atom | Piano Roll 2?

StepPolyArp is rated higher. StepPolyArp averages 4.8 out of 5 from 48 ratings, while Atom | Piano Roll 2 averages 4.5 from 96 ratings.

### Do StepPolyArp or Atom | Piano Roll 2 have ads?

Neither StepPolyArp nor Atom | Piano Roll 2 shows ads.

### Which is updated more often, StepPolyArp or Atom | Piano Roll 2?

StepPolyArp ships an update every 2 months, and Atom | Piano Roll 2 weekly. Most recently, StepPolyArp was updated on October 19, 2026 and Atom | Piano Roll 2 on October 19, 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.*