Comparison
CapyBro vs Grammarly
A solo developer's honest take: I used Grammarly Pro for years, then built a one-time, hotkey-driven alternative for the parts I actually used.
I'm Roman, the developer behind CapyBro, and I paid for Grammarly Pro for years. Most days I used it for two things: fixing grammar and adjusting tone. The plagiarism checker, the AI detector, the 2,000-prompt monthly allowance, the brand-voice profiles, the months I never opened the mobile keyboard — I was renting all of it and barely touching it, while a recurring subscription quietly renewed. So I built CapyBro: a Windows tray utility that rewrites or fixes selected text in any app via a hotkey, using your choice of cloud or fully local AI, for a one-time $19. This page is a fair comparison, not an ad. Grammarly is a more polished, more capable product in several areas, and I say exactly where below, because a comparison that only flatters my own tool would be useless to you.
CapyBro vs Grammarly Pro at a glance
| Feature | CapyBro | Grammarly Pro |
|---|---|---|
| Price | Free core (MIT). Pro is $9 one-time, never a subscription. | $12/mo billed annually ($144/yr), $20/mo quarterly, or $30/mo month-to-month. |
| Billing model | Pay once, own it. 1 device per key, 14-day money-back. | Recurring subscription that renews until you cancel. |
| Platforms | Windows 10/11 x64 only today. macOS on roadmap (~2 months out), Linux later. | Windows, Mac, browser extensions (Chrome/Safari/Firefox/Edge), Microsoft Office (Word/Outlook), iOS/Android keyboard. |
| How it works | Select text in any Windows app, press a hotkey, AI rewrites it in place. | Real-time underlines and a sidebar as you type, in supported surfaces. |
| Real-time scanning | No. It acts only when you select text and press the hotkey. | Yes. Continuous live grammar, spelling, clarity and tone suggestions. |
| AI engine | Your choice: OpenRouter cloud (GPT-4o, Claude, Gemini, DeepSeek, Llama, more) or Ollama fully local. | Grammarly's own cloud models plus integrated generative AI prompts. |
| Offline / local mode | Yes, via Ollama. Text never leaves your PC. | No. Text is processed in Grammarly's cloud. |
| Account required | No account, no login, no email. | Yes. A Grammarly account is required. |
| Telemetry | Zero. No analytics, no tracking. | Cloud service; opt-out available for product-improvement training. |
| Plagiarism checker | None. | Yes, Pro-only; checks documents up to ~5,000 words per scan against web and academic sources. |
| AI detector | None. | Yes, included in Pro. |
| Generative AI limit | No artificial cap. Your own API key sets the budget; local Ollama is unlimited. | 2,000 AI prompts/month on Pro; 100/month on Free. |
| Brand voice / team style guides | None. Single-user, unlimited personal prompts instead. | Yes, brand tones and style guides (team features on Business/Enterprise). |
| Open source | Yes, MIT core on GitHub. | No, proprietary. |
The full story
Is CapyBro a real free Grammarly alternative?
CapyBro is a genuine free alternative for the grammar-fixing and rewriting that many people use Grammarly for, but it is not a feature-for-feature replacement. The entire core workflow — select text anywhere in Windows, hit a hotkey, and have AI fix or rewrite it in place — is free and open source under MIT. There is no trial timer and no nag screen. What it does not replace: Grammarly's live underlines as you type, its plagiarism checker, its AI detector, and its brand-voice features. CapyBro is deliberate — you trigger it on a selection, rather than always-on. If your Grammarly habit was mostly grammar and tone like mine was, CapyBro covers it. If you lean on plagiarism scanning or real-time correction, it does not.
How much does each one actually cost over time?
CapyBro is free for the core, and Pro is a single $9 payment with no renewal, ever. Grammarly Pro is a subscription: $12/month on the annual plan ($144 billed upfront per year), $20/month quarterly, or $30/month month-to-month. Over three years, Grammarly Pro on the annual plan runs about $432, while CapyBro Pro stays at $9 total. That gap was the reason I started building. I was paying a yearly fee that auto-renewed for two features I used daily. With CapyBro you also pay for cloud AI usage if you choose OpenRouter, but that is pay-as-you-go against your own API key — often a few dollars a month for normal writing — and it is zero if you run Ollama locally.
Where is Grammarly genuinely better than CapyBro?
Grammarly is clearly better at several things, and pretending otherwise would be dishonest. Real-time scanning: it underlines mistakes live as you type across web pages and apps, while CapyBro only acts on a selection when you press the hotkey. Plagiarism detection and an AI-content detector: Grammarly Pro includes both; CapyBro has neither. Grammarly also wins on cross-platform reach (Mac, iOS and Android keyboards, browser extensions, Office add-ins), on brand-voice and style-guide tooling, and on onboarding. A non-technical writer installs Grammarly and it just works — no API key, no model choice. CapyBro asks you to pick a backend and paste a key. For many writers, Grammarly's polish is worth the subscription, and I would rather you know that up front.
Does CapyBro work everywhere Grammarly does?
No. CapyBro is Windows 10/11 x64 only today, and I want to be upfront about that. There is no Mac build, no Linux build, no mobile app, and no browser extension. A macOS port via Avalonia is on my roadmap and is roughly two months of work; Linux would come after that. The trade-off is reach. Within Windows, CapyBro works in essentially any app that accepts a text selection — Word, Outlook, Chrome and Edge fields, VS Code, Telegram, Discord, even Steam chat — because it operates at the OS level on selected text rather than through per-app integrations. Grammarly covers more operating systems and devices; CapyBro covers more apps on the one OS it supports today.
How private is each tool?
CapyBro can be fully private; Grammarly is a cloud service by design. In CapyBro's Ollama mode, everything runs locally and your text never leaves the machine. It collects zero telemetry, has no analytics, and needs no account; your API key is stored in Windows Credential Manager, encrypted per-user via DPAPI. There is also optional experimental PII masking before any cloud send. Grammarly requires an account and processes your text on its servers. To its credit, Grammarly states it does not sell your content, encrypts data in transit and at rest, holds recognized security certifications, and lets you opt out of product-improvement training. That is a solid posture, but it is still cloud processing tied to an identity. If you need text to never leave your computer, CapyBro's local mode is the stronger option.
What do I give up by leaving Grammarly?
You give up real-time, always-on correction and a few Pro-only tools. With CapyBro nothing underlines your typos as you write; you decide when to run it. You lose the built-in plagiarism checker and AI detector, the brand-voice and style-guide features, the mobile keyboard, and the browser extension. What you gain is control and cost. You pick the underlying model per prompt if you like, you get a diff preview with an editable result pane before anything is applied, you keep a local history of your last 50 runs, and you stop paying a recurring fee. For a solo writer who mostly wanted clean grammar and a tone shift, that was a trade I was happy to make — which is precisely why I built it.
How do I migrate from Grammarly to CapyBro?
Migration takes about ten minutes and you can keep Grammarly installed while you test. Step 1: install CapyBro from the Microsoft Store (signed, auto-updating, no SmartScreen prompt) or via winget with the command winget install RomanTykhonenko.CapyBro. The direct .exe from GitHub Releases also works but is currently unsigned, so Windows shows Unknown publisher; click More info then Run anyway. Step 2: pick a backend. For cloud, create an OpenRouter API key and paste it in Settings; for fully local, install Ollama and tick the Ollama checkbox. Step 3: learn four hotkeys — Ctrl+Shift+E to fix/rewrite a selection, Ctrl+Shift+Q for the prompt menu, Ctrl+Shift+Z to undo, and Ctrl+Shift+M to switch models (Pro). Step 4: recreate your common Grammarly tasks as custom prompts, for example Fix grammar, Make formal, Make concise. Step 5: use both side by side for a week, then cancel Grammarly from your account billing page once you are confident.
Who is CapyBro actually built for?
CapyBro is built for Windows users who want grammar fixing, rewriting, paraphrasing and translation on demand, without a subscription or an account. It fits developers, privacy-conscious writers, people who work across many desktop apps, and anyone who, like me, mostly used Grammarly for grammar and tone and would rather not pay a recurring fee for it. It is not built for teams that need shared brand voice, for students who specifically need plagiarism scanning, for people who rely on live underlines while typing, or for anyone primarily writing on a Mac or phone today. I am a solo .NET developer, the core is MIT-licensed on GitHub, and I would rather you choose the right tool than oversell mine.
Who should pick which
Frequently asked questions
Is CapyBro really a one-time payment?
Yes. The core is free and open source under MIT. CapyBro Pro is a single $9 payment through Gumroad with no renewal, ever. One key covers 1 device and there is a 14-day money-back guarantee. It is never a subscription.
Does CapyBro have real-time grammar checking like Grammarly?
No. Grammarly underlines issues live as you type. CapyBro is on-demand: you select text in any app and press Ctrl+Shift+E, and the AI fixes or rewrites that selection in place. If always-on scanning is essential to you, Grammarly is the better fit.
Can I use CapyBro completely offline?
Yes, in Ollama mode. CapyBro can run a local model so your text never leaves your computer, with no cloud, no account, and no telemetry. In OpenRouter mode it uses cloud models via your own API key, with optional experimental PII masking before sending.
What does CapyBro Pro add over the free version?
Exactly five things: history export to CSV/JSON, settings backup and restore, a switch-model hotkey (Ctrl+Shift+M), five curated prompt packs (about 50 prompts), and usage statistics. The entire core rewriting workflow is free; Pro is convenience and power-user features.
Does CapyBro work on Mac?
Not yet. CapyBro is Windows 10/11 x64 only today. A macOS port via Avalonia is on the roadmap, roughly two months of work, with Linux later. If you need Mac or mobile support right now, Grammarly is the practical choice.
Is the CapyBro installer safe? I saw an Unknown publisher warning.
The Microsoft Store build is signed and shows no warning, and it auto-updates. The direct .exe from GitHub Releases is currently unsigned, so Windows SmartScreen shows Unknown publisher; click More info then Run anyway. The source is public on GitHub under MIT if you want to inspect it.
How much will cloud AI cost me with CapyBro?
It depends on usage and model. CapyBro itself adds no markup; you pay OpenRouter directly via your own API key, which for normal writing is often just a few dollars a month. Run Ollama locally instead and the AI cost is zero.
Can CapyBro translate and paraphrase, not just fix grammar?
Yes. Because it sends your selection to a capable language model, it can fix grammar, rewrite, change tone, paraphrase, and translate into any language the chosen model understands. You can also add unlimited custom prompts and assign a specific model per prompt.
Why would I switch if Grammarly is more polished?
You might not, and that is fine. Switch if you mostly used Grammarly for grammar and tone, want to stop paying a recurring fee, value an offline/private option, or work across many Windows apps. Stay on Grammarly if you need live scanning, plagiarism checks, an AI detector, brand-voice tooling, or Mac and mobile support.
Try the parts of Grammarly you actually used, for $9 once
CapyBro is free and open source at its core, with an optional $9 one-time Pro tier and a 14-day money-back guarantee. Keep Grammarly installed while you test it, fix and rewrite text anywhere in Windows with a hotkey, and decide for yourself. No account, no telemetry, and a fully local AI mode if you want your words to stay on your machine.
See also
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