Cotabby

Cotabby [beta]

Open-source, local-first AI autocomplete for macOS.

Cotabby is free and open-source — maintained by two students. If it's useful to you, please consider supporting Cotabby's future.

What It Does

Cotabby adds AI autocomplete to almost any text field on your Mac. As you type, a gray suggestion appears inline next to your cursor. Press Tab to accept it a word at a time, or keep typing to ignore it.

The default Apple Intelligence and Open Source engines run on your Mac. No account or telemetry is required. An optional OpenAI-compatible engine can connect to a server you configure.

Demo

Watch on YouTube →

Features

• Ghost-text autocomplete — AI suggestions inline in almost any macOS text field; Tab accepts a word at a time
• Emoji autocomplete — type `` and accept it without leaving the field
• Inline macros — type / for quick math, unit and currency conversion, dates, and random values
• One-key autocorrect — fix a likely typo with a single keystroke
• Prediction controls — choose whether to predict ahead, suggest within words, and show following words
• Optional screen context — control visual context independently of the local prediction settings

Privacy

Privacy is the whole point, so Cotabby's default engines keep generation on your Mac:

• Apple Intelligence and Open Source generation run on-device.
• The optional OpenAI-compatible engine sends a bounded request only to the endpoint you configure;

that endpoint can be loopback, on your local network, or a public HTTPS service.

• No analytics, no telemetry, no crash reporting.
• A normal install never writes what you type to disk.
• Apart from a configured endpoint, the network is used for model downloads and update checks, not

suggestion generation.

Engines

Cotabby generates suggestions in three ways. You choose which in Settings → Engine:

• Apple Intelligence — Apple's model, built into macOS 26 or later on supported Macs. Nothing to download.
• Open Source — a small AI model you download that runs entirely on your Mac. Works on any supported Mac (macOS 14+), with or without Apple Intelligence.
• OpenAI-compatible — a completion or chat endpoint you configure, including local Ollama,

another LAN host, or a public HTTPS service. Endpoint credentials are stored in Keychain.

If your Mac supports Apple Intelligence, that's the easiest place to start. Otherwise, use the Open Source engine and pick one of the built-in models:

Download any of them straight from Cotabby's menu bar.