AI text improvement in one click

CapyBro is a free, open-source (MIT) Windows tray app that rewrites, fixes, or translates selected text with AI on a global hotkey. Select text in any program — Word, a browser, an IDE, an email client — press Ctrl+Shift+E, and the AI improves it in place. It runs natively on .NET 8 (not Electron), works with cloud models via OpenRouter or fully offline via Ollama, and keeps your text private with no telemetry. The core is free forever; an optional one-time $9 Pro adds extras, with no subscription.

Yes. CapyBro's core is free forever and open-source under the MIT license — you can read or build the code on GitHub. There is no trial, no nag screens, and no subscription. An optional one-time $9 Pro upgrade adds premium prompt packs, history export, a model-switch hotkey, and usage statistics, but the free version is the complete hotkey-rewriting workflow.

For now, only Windows 10 and Windows 11 (x64). macOS and Linux versions are not planned — the program uses specific Windows APIs for hotkeys and text-pasting into other programs.

Depends on the mode. In OpenRouter mode — yes, because the AI runs in the cloud. In Ollama mode — NO, the AI runs right on your computer with zero network requests. You can fully disable internet and the program will still work.

Through OpenRouter — all the major ones: GPT-4o, Claude Sonnet, Gemini, Llama, DeepSeek, Mistral, and others (the full list is constantly updated). Through Ollama — any model you've downloaded locally (gemma, llama, mistral, qwen, etc.).

OpenRouter charges per use — you pay per thousand tokens. A typical «fix text» request costs roughly $0.0001–0.001 depending on the model. A $5 top-up on OpenRouter lasts months of active use. CapyBro shows the estimated cost of the request before sending it.

5 premium prompt packs (Legal, Marketing, Academic, Code Review, Business Correspondence), history export to CSV/JSON, a model-switch hotkey that cycles your 3 pinned models, usage statistics, priority email support, and all future updates free — forever.

One-time payment. Pay $9 once — use Pro forever, with all future updates included. No monthly or yearly payments.

One device per key. To use Pro on another PC, remove the license on the old machine first, then activate the key on the new one. Need more? Write to [email protected].

14 days money-back guarantee. Write to [email protected] — I'll refund without unnecessary questions. It's not a marketing trick, it's a real policy.

Yes. The key is stored only on your computer, encrypted via Windows DPAPI (the standard Windows mechanism for secrets). It's never sent to any third-party server except OpenRouter itself. The free version's code is open — you can verify.

Enable Ollama mode. It's a fully local AI that runs on your computer. Install Ollama from ollama.com, download a model (e.g., «ollama pull gemma3»), switch CapyBro to Ollama — and your text never leaves the machine. A moderately powerful computer is needed (8+ GB RAM for small models, 16+ GB is better).

Yes. Gumroad accepts international Visa and Mastercard cards, as well as PayPal and Apple Pay. For Ukrainian cards you may need to enable «internet payments» in your bank app (Privat24, Monobank — that's a setting in card security).

Email: [email protected] — I respond within 1–2 days. Or file an issue on GitHub — there you can also see the full history of known bugs and planned features.

Grammarly is a grammar checker primarily for browsers and Microsoft Office, with a $12+/month subscription. CapyBro is a Windows tray utility that works in any application via a global hotkey — Word, Notepad++, VS Code, Slack, Telegram, your IDE, even single-line input fields. Beyond grammar checking, CapyBro can rewrite, translate, summarise, change tone, or follow any custom prompt you define. Pricing: free forever for the core features; $9 one-time for Pro. No monthly subscription.

ChatGPT Desktop opens a separate window — you have to copy your text in, wait for the response, copy it back. The Windows 11 Copilot key opens a sidebar that only works inside some Microsoft apps. CapyBro stays in your context: select text in any application, press one hotkey, the AI rewrites it where it already is. No copying, no window switching. You also choose the model (GPT-4o, Claude, Gemini, local Ollama) per prompt instead of being locked into one.

Yes. CapyBro uses the global Windows clipboard plus keyboard simulation, so it works in any text input where you can select and paste — including Word, Outlook, OneNote, Excel cells, PowerPoint slides, Teams chat, and all third-party Office add-ins. Workflow is the same as elsewhere: select text → Ctrl+Shift+E → AI rewrites in place.

Yes. Each prompt has a «preserve original language» flag — when enabled, the AI fixes grammar, rewrites, or restyles the text but keeps it in the original language. This works for Ukrainian, Russian, Polish, German, French, Spanish, and any other language the underlying AI model supports. The flag defaults to ON for the built-in «Fix errors» and «Rewrite» prompts; you can configure it per custom prompt in Settings → Prompts.

Yes. The installer is per-user: it places files in %LOCALAPPDATA%\CapyBro\ and registers everything in the current user's profile (no Program Files, no system services, no UAC elevation). CapyBro installs cleanly on locked-down corporate computers where the user account doesn't have admin privileges. The Microsoft Store version goes even further — it installs through the standard Store mechanism with no installer prompts at all.