Cotypist vs Grammarly AI

Cotypist and Grammarly AI are both grammar & style checkers tracked by AIDiveForge. Below is a side-by-side comparison of pricing, capabilities, platforms, and ownership — sourced from each tool's live website and verified before publishing.

Cotypist

Cotypist sits in the macOS menu bar and surfaces word-completion suggestions as you type, accepted with a Tab keystroke, across whichever apps you have open. The differentiating mechanic is per-app instruction profiles: you teach it one voice for client emails, a different register for pull-request descriptions, and it holds those rules separately per application. On-device processing keeps your keystrokes off external servers. The free tier caps daily output at 100 words — a ceiling that arrives fast for anyone with real writing volume. No API, no Windows build, no self-hosting path exists.

Grammarly AI

Grammarly sits in your browser and writing apps, flagging mistakes as you type—grammar, spelling, tone, clarity. It's useful if you write emails, documents, or social posts and want a second pair of eyes without leaving your workflow. The free tier covers basics; Premium ($12/month) adds tone detection and advanced rewrites. The catch: the free version is genuinely limited, and Premium's AI-powered suggestions sometimes miss context or feel prescriptive. It works best for high-stakes writing where accuracy matters more than speed.

Attribute	Cotypist	Grammarly AI
Pricing	Paid	Paid
Price	$6/mo or $9/mo	$12/mo
Free trial	30 days	No
Open source	No	No
Has API	No	Yes
Self-hosted option	No	No
Platforms	macOS	Web, iOS, API
Languages	—	95+ languages
Released	—	2009
Pros	Per-app instruction profiles let you maintain a different writing register for each application, so client emails, Slack messages, and code comments each get the voice you set without manual switching. On-device processing means your keystrokes and draft content are not transmitted to external servers, which matters for anyone working with confidential documents or under data-handling obligations. Tab-to-accept inline completions work inside whichever Mac app has focus, so you never break flow by switching to a separate chat window or sidebar. Multi-Mac profile sync at the paid tier means your per-app voice configuration carries across machines, avoiding the tedious work of reconfiguring from scratch on a second device.	Real-time feedback Grammar and spelling corrections Integrated with popular platforms
Cons	The free tier's 100-words-per-day cap cuts off mid-session for anyone with real writing volume — a journalist drafting a single article, a developer writing commit messages all morning, or a support agent handling a ticket queue will exhaust it before noon and face a choice between upgrading or stopping. There is no Windows version, no Linux path, and no browser extension, so any team that runs a mixed OS environment cannot standardize on this tool — the realistic next step is a browser-based assistant like a Chrome extension that works across platforms. No API means completions cannot be scripted into a build pipeline, a CMS workflow, or any automated process — teams that want completion suggestions integrated into custom tooling have no integration surface and will need a provider that exposes one. The passive suggestion model offers no ability to run multi-step tasks, draft from a prompt, or trigger actions — writers who need to generate a full first draft rather than complete sentences in progress will find the interaction model too narrow and reach for a dedicated generation tool.	Limited free tier accounts Subscription required for advanced features

Bottom line

Only Grammarly AI exposes a public API. Choose based on which difference matters most for your workflow.

Frequently asked questions

What is the difference between Cotypist and Grammarly AI?

Cotypist is Paid, while Grammarly AI is Paid. Compare pricing, free trial, API, platforms, and pros/cons in the table above on AIDiveForge.

Is Cotypist better than Grammarly AI?

It depends on your workflow. Use the side-by-side attributes (pricing, open source, API, self-hosted, platforms) to decide. AIDiveForge does not rank a universal winner — we publish verified facts so you can choose.