Krasp

Krasp is a simple noise-cancellation app for your microphone on macOS.

It works like a lightweight, open-source Krisp-style microphone filter: choose your real microphone in Krasp, turn noise cancellation on, and then select Krasp Microphone in Zoom, Discord, Google Meet, OBS, QuickTime, or any other app.

Krasp is built for a focused idea:

Your microphone
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      v
Krasp removes background noise
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      v
Apps hear Krasp Microphone

The processing runs locally on your Mac. Krasp does not send microphone audio to a cloud service.

What It Does

• Removes background noise from your microphone before other apps hear it.
• Creates a virtual microphone named Krasp Microphone.
• Lives quietly in the macOS menu bar.
• Lets you choose the physical input microphone.
• Lets you adjust how strong the noise cancellation should be.
• Shows simple input and reduction meters while it is running.

Why

Calls, streams, and recordings often pick up fans, keyboard noise, room echo, and other background sound. Krasp is meant to be a small macOS utility that sits between your real microphone and your apps, cleaning the audio path without needing a full audio-routing setup.

It is not trying to be a studio suite. It is a practical microphone noise-cancellation switch for everyday calls and recordings.

Current Status

Krasp is early-stage macOS audio software. The source is ready for public development, and GitHub Actions builds a macOS installer package when app-affecting files change on main.

The current release artifacts are unsigned developer builds. A polished public release still needs Developer ID signing and Apple notarization.

How It Works

Krasp has two parts:

• Krasp.app: the menu-bar app that captures your selected microphone and applies noise cancellation.
• KraspHAL.driver: the virtual microphone driver that exposes the cleaned audio as Krasp Microphone.

Under the hood, Krasp uses Hush/DeepFilterNet for neural speech enhancement. If the neural runtime cannot load, it falls back to a simpler local DSP path.

More detail is in Architecture.

Requirements

• macOS 14 or newer.
• Xcode command-line tools with Swift 6.1 support.
• Rust toolchain with Cargo.
• Internet access for the first neural build, which downloads Hush and clones DeepFilterNet.

Build

Build the app:

make app

Run it:

make run

Build a macOS installer package:

make dist

Artifacts are written to dist/.

Install The Virtual Microphone

1. Build and launch Krasp with make run.
2. Click Install in the Virtual Microphone row.
3. Approve the macOS administrator prompt.
4. Select Krasp Microphone as the input device in your call, recording, or streaming app.

The app installs its embedded HAL driver to:

/Library/Audio/Plug-Ins/HAL/KraspHAL.driver

and restarts CoreAudio so macOS can discover the virtual microphone.

Release

GitHub Actions builds and publishes a GitHub prerelease when app-affecting files change on main. Pushing a tag like v2026.1.1 also creates a tagged prerelease with the .pkg and checksum attached.

Release workflow notes are in Release.

Third-Party Components

• Hush model by Weya AI, Apache-2.0.
• DeepFilterNet/libDF by the DeepFilterNet authors, Apache-2.0 or MIT.

See Third Party Notices.

License

Krasp source code is released under the MIT License. See LICENSE.