MJSFX

MJFX brings sounds and effects creation onto the macOS platform with a native Silicon app, curated starting points, layering, effects and modulation (LFOs), paired with MIDI hardware control, extensive keyboard shortcuts, and developer-friendly JSON files.

• Sound files (and all config files) are JSON
• Generators to get you started: pickups, lasers, explosions, jumps, hits, etc.
• Layer multiple voices, each with its own controls
• Per-layer and main sound effects chain
• LFOs that can modulate almost anything including itself and other LFOs
• Mutate or randomize; undo on everything
• WAV export at 44.1/22/11 kHz, 16 or 8-bit, plus per-layer stems
• Keyboard shortcuts for (almost) everything
• Custom MIDI controller support (create your own config)
• Themes: light, dark, and a theme builder on the site
• No in-app AI, but the direct download (and homebrew) version ships with an MCP server

Free. Fully offline. No accounts, no network access (except Sparkle updater), no telemetry, no ads.