Comparison

Sidecar MIDI Controller vs SFX Library

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

Head to head
About

Sidecar MIDI Controller

Transform your QWERTY keyboard or game controller into a powerful MIDI controller for your iOS music apps. Play melodies, trigger chords, and adjust synth parameters with ease, even while running other apps in the background.

Highlights
  • QWERTY keyboard piano mapping
  • Configurable pads for notes, chords, and messages
  • Scale-configurable virtual keyboard
  • Game controller support
  • AUv3 plugin integration
  • Slide-over and side-by-side mode compatibility
Features
Read full description

There are hundreds of great iOS synth apps, but playing them with on-screen keyboards can be a challenge. Sidecar turns your ordinary QWERTY keyboard into a powerful MIDI controller.  The lower part of the keyboard is mapped piano-style, letting you play melodies with the physical keys -- much easier to keep your fingers in the right place, and to get the notes you want. The app is configurable; you can have ten different set-ups, and switch between them quickly with a tap on the "QWERTY" row. There are also ten configureable pads for each set-up, which you can trigger with the number keys. Each pad can play a specific note, a chord, generate a program change message, or send a control code. Because Sidecar operates in slide-over and side-by-side mode on the iPad, you can use your physical keyboard with any MIDI app, even if the other app is running in the background. On screen, you have access to each of the pads -- map the knobs and sliders of your synth apps to MIDI CC messages, and then use Sidecar to adjust these sliders as you play. Sidecar also provides a scale-configurable virtual keyboard. Pick the scale you want, and then you can't hit a wrong note. In addition to external keyboards, Sidecar also supports many game controllers. The app is now universal; while the iPhone doesn't support slide-over, you can still take advantage of the configuration options of the app. * Easy MIDI Configuration With ten separately configurable MIDI destinations you can quickly set up a set of assignments for each of the MIDI apps that you use. Have a set of chords for Animoog, choose different presets for ToneStack, or assign pads to different samples for DM1. Each MIDI destination has ten configurable pads, which can be assigned to chords, single notes, a program change message, or a controller change message. For notes and chords, the touch position controls note velocity. For controller change messages, the location of a touch on screen can be used to determine the controller value. * QWERTY Keyboard Support Toggle on support for the external keyboard, and you can switch between the ten MIDI destinations quickly (using the keys in the QWERTY row). Toggle on or off any of the ten pads by pressing the number keys. The two lowest rows of keys are mapped as a standard piano keyboard, providing a musical play surface with an ordinary text keyboard. Note that QWERTY keyboards only send "key press" information to your iPad -- to silence a sounding note, you simply tap the space bar. * AUv3 Support Add the plug-in to your favorite DAW or looper, and Sidecar will give you easy access to multiple synths. Many AUv3 hosts will also let you map the keyboard keys to the transport controls. * Game Controller Ready Sidecar also supports the iON iCade game controller, mapping the buttons of the iCade to the pads. Because the iCade was designed for games, it sends button press and release information, which makes it easy to toggle on and off the pads. * MIDI Relay If you have an external MIDI controller, you can have it send MIDI events to Sidecar -- and these will be relayed to any of the ten MIDI destinations you select. Use this to quickly switch from one synth to another. *Control Background Synths Because Sidecar sends MIDI messages, it can be used to control background synthesizers, sequencers, and effects apps. Sidecar is designed to work along side your other iOS music apps.

About

SFX Library

Access a vast collection of copyright-free sound effects directly on your mobile device. Play audio clips instantly for your projects or enjoyment.

Highlights
  • Copyright-free sound effects library
  • Instant audio playback
  • On-device access
  • Wide range of audio clips
Features
Read full description

The SFX Library app allows you to quickly play sound effects from a library of copyright-free audio directly on your device.

Screenshots

Sidecar MIDI Controller3 screens
SFX Library2 screens

Verdict

The call

The clearest difference is price: SFX Library at Free against Sidecar MIDI Controller's $4.99. SFX Library also leads on update cadence (every 3 weeks vs every 3 months). Sidecar MIDI Controller's advantage is ads (none vs shown) and ratings volume (14 vs 1). On rating, in-app purchases, device support and iOS requirement 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

SFX Library is free to download; Sidecar MIDI Controller costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.9 for Sidecar MIDI Controller against 5.0 for SFX Library. That said, the two scores are not equally well evidenced: Sidecar MIDI Controller has 14 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

Sidecar MIDI Controller ships an update every 3 months, SFX Library every 3 weeks. The most recent releases landed on October 13, 2026 and October 9, 2026 respectively.

Scorecard5 real differences · 5 level
Sidecar MIDI Controller versus SFX Library: the parameters behind the verdict, then further details
ParameterSidecar MIDI ControllerSFX Library
Price$4.99Free — better
Rating4.9 (14 ratings)5.0 (1 ratings) — better
Positive reviews76.2% of reviews—
Number of ratings14 — better1
Update frequencyEvery 3 monthsEvery 3 weeks — better
AdsNo — betterYes
In-app purchasesNoNo
MonetizationPaidAd-supported — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.614.0 — better
Further details — not scored
Size6 MB30 MB
Age rating4+4+
DeveloperSecret Base DesignJonathan Stinson

Customer experience

Sidecar MIDI Controller

All ratings14 ratings
Positive92.9%
Neutral7.1%
Negative0.0%
Written reviews21 reviews
Positive76.2%
Neutral4.8%
Negative19.0%

SFX Library

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Sidecar MIDI Controller

No in-app purchases

None

SFX Library

No in-app purchases

Questions

Is Sidecar MIDI Controller free?
Sidecar MIDI Controller costs $4.99, with no in-app purchases.
Is SFX Library free?
SFX Library is free to download, with no in-app purchases.
Which has better reviews, Sidecar MIDI Controller or SFX Library?
SFX Library is rated higher. Sidecar MIDI Controller averages 4.9 out of 5 from 14 ratings, while SFX Library averages 5.0 from 1 ratings.
Do Sidecar MIDI Controller or SFX Library have ads?
SFX Library shows ads; Sidecar MIDI Controller does not.
Which is updated more often, Sidecar MIDI Controller or SFX Library?
Sidecar MIDI Controller ships an update every 3 months, and SFX Library every 3 weeks. Most recently, Sidecar MIDI Controller was updated on October 13, 2026 and SFX Library on October 9, 2026.

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