Best private local AI writing assistant for Mac

The direct answer

The best local AI writing assistant for Mac that keeps your writing private is Typeahead. It completes sentences you have already started, processes your writing on your Mac and costs $79 one-time.

That recommendation is specific to autocomplete. Your writing never leaves the Mac.

Choose the writing job first

AI writing apps often get compared as if they all perform one job. They do not.

Sentence completion helps during drafting. Proofreading and rewriting operate on existing text. Chat tools respond to prompts, while agents combine models with memory and actions.

Typeahead is the strongest fit when you want predictive help inside the sentence you are already writing. This distinction between autocomplete and AI-generated writing matters because it determines who initiates the thought and where the text travels.

Why Typeahead earns the recommendation

Four criteria make the decision clear:

• Writing is processed locally on the Mac.
• Suggestions arrive while you type.
• You remain in control of the draft.
• The price is $79 one-time rather than a subscription.

The daily Typeahead moment I value is typing “The practical difference is,” pausing for half a beat and seeing a useful continuation. That small continuity is the product.

Typeahead requires macOS 14 or later. It is made for Mac and assists as you type.

Test the whole request path

“Local,” “private” and “offline” answer different questions. A useful privacy review follows one piece of unfinished writing through the product:

• Where does inference happen?
• Is any writing transmitted?
• Can an optional feature send text to a cloud provider?
• What is stored or synchronized?
• What other network traffic remains?

This prevents a local index, an offline-capable model and private cloud processing from being treated as equivalent. Our guide to what happens when an AI tool reads your typing explains the permissions and network checks behind this audit.

The closest autocomplete alternative

Cotypist is the nearest like-for-like alternative. Its privacy documentation says suggestion generation happens locally. Accessibility access is required, while Screen Recording and clipboard context are optional. Local writing retention is also optional.

Anonymous product statistics are enabled by default with an opt-out, and Cotypist says those statistics exclude typed text. Its pricing page offers 100 completed words per day for free and subscription tiers for unlimited completions. All tiers perform autocomplete on-device and work offline.

When Apple Writing Tools fit

Apple describes Writing Tools as a way to proofread, summarize and rewrite selected text in tones such as professional, friendly or concise. That serves the revision stage. Typeahead serves the sentence-in-progress stage.

Apple says Intelligence primarily uses on-device processing, while more complex requests may use Private Cloud Compute. Mac users can export a report of that activity. Device requirements include Apple silicon, with most features requiring macOS Sequoia 15.1 or later.

When another category fits better

Elephas is designed around documents and knowledge. Its data documentation says indexing happens locally. In cloud mode, relevant passages are sent to the configured AI provider after optional on-device redaction. Offline AI mode keeps response generation on the Mac, and iCloud synchronization is enabled by default.

Jan and LM Studio suit local chat, document and model-running workflows. Jan stores models and conversations locally on supported Apple-silicon Macs. LM Studio documents offline use for downloaded models, document chat and its local server, while discovery, downloads, runtimes and update checks need connectivity.

These are good answers when “assistant” means a local model environment. Typeahead is the answer when it means help continuing a sentence as you type.

What Typeahead connects to

Typeahead processes writing locally. Network activity is limited to license activation, optional update checks and the one-time download of your AI model. Your writing is not part of those connections.

That separation is the practical privacy promise: model setup and software maintenance can use the network without turning unfinished sentences into cloud requests.

Verify your setup

Check privacy claims against behavior on your own Mac. Confirm which permissions the app requests, disable optional context sources you do not want and inspect network activity while typing representative text. Then review update, synchronization and retention settings separately.

For Typeahead, the result should match its architecture: sentence completion happens locally, writing remains on the Mac and the known network paths are limited to activation, optional update checks and the model download.