Building a Low-Latency Audio Palette for Desktop with Flutter & Sidecar

Muhammed Shabeer OP — Mon, 27 Apr 2026 09:32:38 +0000

As a creator, I kept running into the same issues with soundboard apps: they were bulky, slow to respond, or just awkward to use in live setups. So I built PadVibe—a desktop-focused audio pad designed to be fast, minimal, and easy to work with.

Key Features

Low-latency playback using SoLoud
Flexible output routing for multi-device setups
Drag-and-drop mapping for quick setup
Global hotkeys that work across applications
Open source and available on GitHub

Tech Stack

Flutter (Desktop): Used for the UI layer.
Python (Sidecar): Handles the heavy lifting for audio processing.
GetX: Manages the application state.
GitHub Actions: Automates our builds and releases.

Challenges

Latency: Many audio libraries introduced noticeable delay. Using Sidecar helped keep playback responsive enough for live use.
Desktop behavior: Handling things like global shortcuts, window layering, and transparency took extra work to feel native.

Links

shabeer-wms / padvibe

PadVibe — cross‑platform Flutter app (macOS‑first) with drag‑and‑drop, multi‑window, file picking, and SoLoud‑based audio.

PadVibe 🎚️

PadVibe is a professional-grade, cross-platform audio sample triggering application. It combines the expressive UI capabilities of Flutter with a high-performance Python Sidecar audio engine to deliver low-latency playback, advanced routing, and real-time DSP.

🏗️ Architecture: The Sidecar Pattern

PadVibe employs a unique Dual-Engine Architecture. While Flutter handles the complex UI and state management, a dedicated Python process (the "Sidecar") manages the heavy lifting of audio and MIDI.

🔌 Communication Flow

Flutter (Client): Sends JSON commands via WebSockets.
Dynamic Port Discovery: The Sidecar automatically finds an available port (8765-8775) and broadcasts it to Flutter for a seamless handshake.
Python Sidecar (Server): Executes audio playback, DSP, and MIDI polling.
Real-time Feedback: The Sidecar streams audio levels (RMS/Peak) and MIDI events back to Flutter for immediate UI updates.

✨ Key Features

🎧 Pro Audio Engine

Multi-Device Routing: Assign individual pads to specific hardware output channels or different audio interfaces…

View on GitHub

PadVibe | The Premium Audio Palette for Creators

Master your audio flow with PadVibe. The zero-latency audio palette for professionals.

padvibe.pro26.in

Next Steps

I’m planning to add mixing controls and possibly a mobile companion for remote triggering.

If you’ve worked with Flutter on desktop or low-latency audio, I’d love to hear about your experience. Specifically, did you run into similar window layering issues on macOS vs Windows? Let's discuss in the comments!

DEV Community: Muhammed Shabeer OP