Simbi

Stop paying twice for AI.
Use your ChatGPT plan for live, speaker-labelled meeting transcripts, saved as plain files.

Download for Apple silicon · Documentation · Website

Simbi is a free, open-source macOS app that records your microphone and system audio, identifies speakers locally, and builds a live transcript. When the recording ends, it turns the conversation into editable AI Notes with citations that jump back to the original audio.

It pairs a native, local audio engine with the ChatGPT app you already use. Speaker detection happens on your Mac. Transcription, transcript cleanup, summaries, file conversion, and chat run through your own ChatGPT account. No separate Simbi account or API key is needed.

Why Simbi

• Your notes stay yours. There is no database or proprietary format. Notes are Markdown, transcripts are WebVTT, recordings are WebM/Opus, and every note is an ordinary folder you can open in Finder.
• Both sides of the conversation. Simbi captures your microphone and system audio into one synchronized timeline, without a bot joining the call.
• Live speaker-labelled transcripts. Local voice activity detection and diarization divide the conversation into clean per-speaker segments before transcription.
• AI Notes grounded in the recording. Summaries include clickable timestamp citations. Select one to hear the source moment and verify what was said.
• Context, not copy and paste. Add PDFs, slide decks, documents, or spreadsheets. Simbi preserves the originals and creates Markdown context for transcript cleanup, summaries, and chat.
• Codex you can inspect and steer. Transcript fixing, conversion, summaries, titles, and note chat are real Codex threads. Their Markdown instructions are yours to edit.
• Built to survive the meeting. Audio streams directly to a valid file, and pending transcript segments are queued on disk. A quit, crash, or lost connection does not throw away the recording.

Simbi doesn't reinvent the wheel

The hard parts are already solved, and solved well. Simbi assembles mature open-source projects and spends its own code on the glue: mixing two audio sources onto one timeline, deciding where to cut speech, and keeping every note a plain folder.

• Codex CLI for agent threads
• Ghostty for the embedded terminal
• FluidAudio for on-device speech processing
• anydoc for file conversion
• swift-markdown-engine for Markdown editing
• Sparkle for app updates

See Third-Party Licenses for the complete list.

Every note is just a folder

~/Simbi/Work/Weekly Sync/
├── note.md          your notes
├── summary.md       AI Notes with timestamp citations
├── transcript.vtt  timed, speaker-labelled transcript
├── audio.webm       complete recording
├── files/           untouched attachments
└── context/         Markdown copies for Codex

Open the same folder in Obsidian, version it with Git, sync it with iCloud, or search it with rg. Changes made outside Simbi appear in the app too. The full layout, recovery state, and editable agent instructions are documented in How Simbi stores notes.

Install

You need:

• An Apple silicon Mac
• macOS 14.0 or later. System-audio capture requires macOS 14.4 or later
• The ChatGPT desktop app, installed and signed in

Then:

1. Download the latest notarized DMG.
2. Drag Simbi to Applications and open it.
3. Choose a notes folder, grant the requested audio permissions, and let Simbi download its local speech models once.
4. Create a note and press record.

Simbi checks for signed updates with Sparkle. Update checks can be changed or disabled in Settings.

Privacy, without hand-waving

Simbi has no backend, user accounts, analytics, crash reporting, ads, or tracking. The developer never receives your notes, recordings, or transcripts.

The processing boundary is:

• On your Mac: microphone and system-audio capture, the complete recording, voice activity detection, speaker diarization, note storage, and recovery queues.
• Sent directly to OpenAI under your ChatGPT account: short audio segments for transcription, plus note, transcript, and attachment content when the corresponding Codex features run.
• Other network access: one-time public model downloads from Hugging Face and optional app updates from GitHub.

Nothing passes through a Simbi-operated server. Read the complete privacy policy before using Simbi with sensitive conversations. You are responsible for obtaining any consent required to record other people; see the terms of use.

Learn more

• Getting started
• How transcription works
• AI Notes, titles, and playback
• Chat with your notes
• Adding files as context
• Settings and agent instructions

Build from source

The app requires Xcode 26 or later, Swift 6, XcodeGen, and a Rust toolchain. Rust is used at build time to vendor the pinned anydoc converter CLI.

git clone https://github.com/predict-woo/simbi.git
cd simbi
brew install xcodegen
xcodegen generate
open Simbi.xcodeproj

To launch a local build, select your Apple development team for the Simbi target under Signing & Capabilities.

The Swift packages contain the app's real logic and build independently of the Xcode shell:

swift build --package-path Packages/SimbiKit
swift test --package-path Packages/SimbiKit

For a command-line app build that matches CI:

xcodebuild -project Simbi.xcodeproj -scheme Simbi \
  -destination 'platform=macOS' build CODE_SIGNING_ALLOWED=NO

The first app build runs scripts/fetch-anydoc.sh. It downloads a pinned crate, verifies its SHA-256 checksum, and builds the helper for every installed macOS Rust target.

Architecture

App/                              thin SwiftUI app and Sparkle wiring
Packages/SimbiKit/Sources/
├── SimbiKit/                     plain-file notes, settings, VTT, recovery state
├── SimbiAudio/                   capture, mixing, diarization, encoding, playback
├── CodexKit/                     ChatGPT/Codex integration and worker threads
└── SimbiUI/                      native macOS interface
project.yml                       source of truth for the generated Xcode project

The package-first layout keeps almost all work testable with SwiftPM. For the deeper contracts, start with the product specification, the recording algorithm, and the design system.

Contributing

Bug reports, ideas, and focused pull requests are welcome. Please open an issue before a large change so the direction can be agreed on first. For code changes, run the Swift tests and the toolchain formatter before opening a pull request:

swift test --package-path Packages/SimbiKit
swift format lint --strict --recursive \
  App Packages/SimbiKit/Sources Packages/SimbiKit/Tests Packages/SimbiKit/Package.swift

License

Simbi is released under the MIT License. Third-party software and model notices are listed in THIRD-PARTY-LICENSES.md.

Simbi is an independent project and is not affiliated with or endorsed by OpenAI, Apple, NVIDIA, GitHub, or Hugging Face.