Comparison

IMPSY vs Fishtail

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

Head to head
About

IMPSY

This app acts as an AI MIDI partner, improvising musical responses to your playing. It can be used as an AUv3 plugin in DAWs or standalone, offering customizable AI models and MIDI mapping.

Highlights
  • AI-powered musical improvisation
  • AUv3 MIDI Processor for DAWs
  • Standalone Core MIDI virtual ports
  • Customizable AI model loading
  • Extensive MIDI mapping options
  • VoiceOver and Dynamic Type support
Features
Read full description

Jam with an AI MIDI partner on iPad and iPhone. IMPSY listens to what you play and improvises musical responses. Load it as an AUv3 MIDI Processor in AUM, AudioBus, Cubasis or Logic Pro for iPad, play it from a USB or Bluetooth controller (or the on-screen faders), and route its output to any instrument app. IMPSY also runs on its own: it appears as Core MIDI virtual ports (IMPSY In / IMPSY Out) and connects directly to a plugged-in controller, so you can play it without a DAW. How it works IMPSY runs a Mixture Density Recurrent Neural Network (MDRNN) on-device. Every note, control change or pitch-bend you send becomes input to the model, which predicts what comes next, including the timing of the response. Shape the conversation with: • Threshold: how long IMPSY waits between your input and its reply • Sigma Temperature: randomness of pitch and control values • Pi Temperature: randomness of which musical "idea" the model picks • Timescale: speeds up or slows down the response • MIDI Thru: passes your own playing through to the output alongside IMPSY's Connect anything • Map each model dimension to any MIDI message (notes, CCs or pitch-bend) on any channel, independently for input and output • Connect a controller directly, or use the always-on IMPSY In / IMPSY Out virtual ports • Import and export your mappings as TOML, compatible with the IMPSY Python toolkit Custom models IMPSY ships with a default 9-dimensional model trained for general musical interaction, but you can load any .tflite model trained with the open-source IMPSY research toolkit: synths, drum machines, lighting rigs, or anything that speaks MIDI. Accessibility IMPSY is built to work with VoiceOver and Dynamic Type. Every control is labelled, the sliders are adjustable by VoiceOver, and status shows as text, not colour alone. Full statement: charlesmartin.au/impsy-auv3/accessibility.html Compatibility • AUv3 MIDI Processor, no audio I/O • Hosts in AUM, AudioBus, Cubasis and Logic Pro for iPad, or any other AUv3 host that supports midi processors. • Also runs standalone with Core MIDI virtual ports and direct device connection • Requires iOS 17 • MIDI stays on-device. No network, no telemetry

About

Fishtail

This app generates complete musical forms using algorithmic composition based on music theory. Users can shape, perform, and rearrange these compositions, routing seven musical channels to their chosen instruments via MIDI. It offers extensive control over keys, modes, and expressive elements.

Highlights
  • Algorithmic music generation
  • Multi-section compositions
  • Seven-channel MIDI output
  • Retain, reorder, and perform Takes
  • Multiple intonation systems
  • AUv3 MIDI plug-in support
  • Ableton Link integration
Features
Read full description

Fishtail is a generative MIDI instrument for iPhone and iPad. It composes complete musical forms, then lets you shape, perform, retain and rearrange them! Explore six composers, including Lumière’s evolving modal colour and Ritual Engine’s rhythmic energy. Roll D7 for a shaped recipe, then Generate and edit it. Fishtail does not use AI to generate music. Its musical output is created through algorhythmic generation grounded in musical theory. Build pieces from sections with independent keys, modes, meters, cadences and expressive treatments. Generate distinct Takes, compare them, reorder them and hand the next Take over at a natural whole-piece boundary. Fishtail produces MIDI rather than sound. Use it standalone or as an AUv3 MIDI plug-in, and route its seven musical channels to the instruments you choose. Ableton Link supports shared tempo and transport. Features: • Complete multi-section generative compositions • Seven-channel MIDI output • Retain, reorder and perform Takes • Seven intonation systems • Normal MIDI, pitch-bend and MPE output • MTS output • Ableton Link • .fishtail project save and recall • Standard MIDI and per-channel export • Experimental analogue CV file packages • Accessible light and dark interfaces No account, advertising, analytics or tracking. Tested in AUM

Screenshots

IMPSY4 screens
Fishtail3 screens

Verdict

The call

The clearest difference is price: IMPSY at Free against Fishtail's $14.99. IMPSY also leads on rating (4.5 vs 4.3). Fishtail's advantage is update cadence (every 3 days vs every 4 months) and ratings volume (6 vs 2). On ads, 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

IMPSY is free to download; Fishtail costs $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

IMPSY holds the better App Store score, 4.5 against 4.3. Both are backed by a comparable volume of ratings — 2 and 6 respectively.

UpkeepUpdate frequency

IMPSY ships an update every 4 months, Fishtail every 3 days. Both last shipped on October 17, 2026.

Scorecard5 real differences · 5 level
IMPSY versus Fishtail: the parameters behind the verdict, then further details
ParameterIMPSYFishtail
PriceFree — better$14.99
Rating4.5 (2 ratings) — better4.3 (6 ratings)
Positive reviews—50.0% of reviews
Number of ratings26 — better
Update frequencyEvery 4 monthsEvery 3 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
DevicesiPhone, iPad, Mac — betteriPhone, iPad
Requires iOS17.017.0
Further details — not scored
Size18 MB37 MB
Age rating4+4+
DeveloperCharles MartinAMY NICOLA MCBRIDE

Customer experience

IMPSY

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Fishtail

All ratings6 ratings
Positive83.3%
Neutral0.0%
Negative16.7%
Written reviews2 reviews
Positive50.0%
Neutral0.0%
Negative50.0%

In-app purchases

None

IMPSY

No in-app purchases

None

Fishtail

No in-app purchases

Questions

Is IMPSY free?
IMPSY is free to download, with no in-app purchases.
Is Fishtail free?
Fishtail costs $14.99, with no in-app purchases.
Which has better reviews, IMPSY or Fishtail?
IMPSY is rated higher. IMPSY averages 4.5 out of 5 from 2 ratings, while Fishtail averages 4.3 from 6 ratings.
Do IMPSY or Fishtail have ads?
Neither IMPSY nor Fishtail shows ads.
Which is updated more often, IMPSY or Fishtail?
IMPSY ships an update every 4 months, and Fishtail every 3 days. Most recently, IMPSY was updated on October 17, 2026 and Fishtail on October 17, 2026.

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