WretchUp vs Robot Butter
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
WretchUp
This app offers a unique audio manipulation experience, allowing users to create sonic mayhem with pitch-shifted delays, filters, and sampling. It's designed for live performance and studio use, enabling musicians and sound enthusiasts to generate wild noises and unique effects.
- Pitch-shifted delay with feedback and filter
- Live performance-oriented controls
- Gesture-based play
- Record vocals and instruments
- Sample and manipulate loops
- Inter-App-Audio and Audiobus support
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An effect instrument anyone can play - sonic anarchy in the palm of your hand. iOS Mars: "Barely controlled chaos“, "sonic extremes“, "well suited for live use“ Music App Blog: "if you like the occasional dose of sonic mayhem, then this is an app that will let you make it" WretchUp is the sonic instrument from the imagination of Mouse on Mars Instruments. Used by the duo in their live performances, it's a playable effect inspired by analog hardware. Sing into it, speak into it, plug in an instrument, sample sounds, and then make sonic mayhem. It's been tested in Mouse on Mars' live shows and used in studio albums. But now it's available to anyone - whether you're a musician wanting to create unique sounds or you just want to make some wild noises and frighten friends and enemies. // FEATURES - Pitch-shifted delay with feedback and filter - Unique controls, designed to be used in live performance and tested onstage - Play with gestures, even without looking closely at the screen - Record vocals or instruments from the built-in mic or another input - Sample loops and change their speed - Adjust the feedback loop, pitch, and filter for unique sounds - Make inputs by holding down your finger, or lock input for continuous sampling - Inter-App-Audio supported - Audiobus supported www.mouseonmars.com/mominstruments Features artwork by Rupert Smyth. Pure Data-based, open source patch created by Florian Grote and Peter Kirn with Mouse on Mars. App design by Oliver Greschke. Powered by free and open source software libpd. Note: like all mic-based effects, you need to enable microphone input. If you accidentally did not allow mic input, you can allow later via: Device settings, WretchUp, Data settings, Microphone, allow mic input.
Robot Butter
This audio effect app creates dynamic soundscapes by blending animated modulation, adaptive reverb, and digital textures. It offers a fast, playable interface with direct control over key parameters and tempo-synced movement for evolving sound design.
- AUv3 audio effect for iPhone, iPad, and macOS
- Animated modulation engine
- Adaptive reverb stage
- Tempo-synced LFO matrix
- Digital texture effects
- Built-in user manual
- Factory and user presets
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Robot Butter is a creative AUv3 audio effect for compatible hosts on iOS & iPadOS. It blends animated modulation, adaptive reverb, tempo-aware movement, and digital texture into one fast, playable interface. At the core is the Robot engine, where Actuator, Viscosity, and Controller create the main motion and character of the signal. That signal then feeds Butter, an adaptive reverb stage designed to intelligently stay musical while responding to the effective movement of the Robot section. The result can move from focused width and pulse to washed ambience, strange motion, and unstable experimental color. The Chipset section extends the sound with a built-in assignable LFO matrix and a post-reverb System Bus reduction stage. Run the LFO freely in Hz or lock it to musical divisions for host-synced movement, then route it to key Robot or Butter controls for evolving motion. Add System Bus for subtle grain or push it harder for sharper, crushed digital edge. Robot Butter is designed to stay immediate. The interface gives you direct control over modulation, blend, depth, reverb shape, output mix, and motion timing without pushing you into a complicated modulation environment. A built-in user manual inside the standalone app includes overview pages, parameter explanations, quick-start guidance, glossary entries, MIDI notes, and troubleshooting help, with scrollable section pills that keep longer labels readable. Factory presets and user presets make it easy to jump from polished mix enhancement to stylized movement and aggressive sound design. Features: - Robot modulation engine with Actuator, Viscosity, Controller, and gain staging - Butter adaptive reverb with Churn, Emulsion, and Culture controls - Built-in LFO matrix with free or tempo-synced timing - Assignable LFO destinations across Robot and Butter parameters - System Bus sample-rate reduction stage for animated digital texture - Imaging modes including Mono, Wide, Ping, and Drift when stereo processing is available - Factory presets covering vocals, guitars, bass, keys, synths, drums, utility, and experimental categories - User preset save, recall, and delete support - Comprehensive built-in in-app user manual with quick-start, glossary, and troubleshooting sections - MIDI Learn, Host Learn support, and default CC mappings for hands-on control - Optional MIDI CC broadcast for compatible host-routing workflows - Host tempo sync with straight, dotted, and triplet divisions Use Robot Butter for vocal movement, guitar widening, synth pulse, drum bus animation, ambient wash design, or aggressive lo-fi modulation chains. It is built to move quickly from musical enhancement to animated destruction while keeping the workflow focused and playable.
Screenshots
Verdict
The clearest difference is price: WretchUp at $4.99 against Robot Butter's $14.99. WretchUp also leads on ratings volume (9 vs 2) and iOS requirement (11.0 vs 17.0). Robot Butter's advantage is rating (5.0 vs 3.1) and review sentiment (100% vs 91%). On update cadence, ads, in-app purchases and monetization model 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
WretchUp costs $4.99 and Robot Butter $14.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Robot Butter holds the better App Store score, 5.0 against 3.1. Both are backed by a comparable volume of ratings — 9 and 2 respectively. Written reviews point the same way: 91% of WretchUp's written reviews are positive against 100% of Robot Butter's.
WretchUp ships an update every 3 weeks, Robot Butter monthly. The most recent releases landed on October 3, 2026 and October 17, 2026 respectively.
| Parameter | WretchUp | Robot Butter |
|---|---|---|
| Price | $4.99 — better | $14.99 |
| Rating | 3.1 (9 ratings) | 5.0 (2 ratings) — better |
| Positive reviews | 90.9% of reviews | 100.0% of reviews — better |
| Number of ratings | 9 — better | 2 |
| Update frequency | Every 3 weeks — better | Monthly |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Paid |
| Devices | iPhone, iPad, iPod | iPhone, iPad, Mac, Vision Pro — better |
| Requires iOS | 11.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 15 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | MoMinstruments GbR | Christian Thompson |
Customer experience
WretchUp
Robot Butter
In-app purchases
WretchUp
No in-app purchases
Robot Butter
No in-app purchases









