What CapyBro Does

CapyBro is a free AI writing assistant for Windows that can fix, rewrite, translate, or improve text in almost any application with a keyboard shortcut. If you write enough emails, code comments, and messages, fixing every typo by hand gets old, and this is awesome for that. I’m dyslexic and found using this as a tool to bulk edit my writing was a huge time saver. . It supports cloud AI via OpenRouter or local models via Ollama, so you can choose between convenience and keeping everything on your own PC.

CapyBro adds AI-powered text editing to Windows without forcing you to work inside another chat app or browser tab. Select some text, hit the hotkey, choose what you want done, and CapyBro processes it using your configured AI model.

The idea is simple, and that's probably why it works so well. The name is a little weird, but it's based on the capybara used for the logo, so we'll allow it.

Why Someone Would Use This Tool

The biggest advantage is that CapyBro works where you're already typing.

For example, open Notepad and type a paragraph full of spelling mistakes, awkward sentences, or whatever else your fingers managed to produce. Select it and press Ctrl+Shift+E. The CapyBro window pops up, you tell it to clean up the text, and the corrected version can go right back into Notepad.

That's much faster than selecting the text, copying it, opening an AI website, pasting it, writing a prompt, copying the answer, switching back to Notepad, and pasting it again. Do that twenty times a day, and the appeal becomes obvious.

It's particularly useful for dyslexic users. Instead of stopping every few words to fight with spelling and grammar, you can get your thoughts down first and let CapyBro clean things up afterward. That's a genuinely useful application of AI rather than AI being bolted onto something because apparently everything needs AI now.

The same trick works when writing emails, documentation, forum posts, code comments, reports, or messages.

Cloud AI or Local Ollama Models

CapyBro doesn't lock you into one AI service. You can configure it with an OpenRouter API key and use supported cloud models, or connect it to Ollama and run compatible models locally.

OpenRouter is an online service that provides a single API key to access and switch between AI models from providers such as OpenAI, Anthropic, Google, and others. This is the easier route if your computer isn't particularly powerful. You provide your own API key, choose a model, and CapyBro sends the request through that service. Keep in mind that "free software" doesn't necessarily mean free AI requests. Depending on the model you choose, API usage can cost quite a bit of money.

Ollama is more interesting for privacy-conscious geeks. With a suitable local model, the processing happens on your own machine instead of sending the text to a cloud AI provider. The tradeoff is hardware. Running a decent local model on an older PC with limited RAM can turn a quick grammar fix into an opportunity to go make coffee and mow the lawn, while the LLM does its thing.

Useful Features Worth Knowing

Custom prompts are where CapyBro becomes more than a fancy spell checker. Instead of typing the same request every time, you can save prompts for jobs you perform regularly.

You can build prompts around the way you actually write rather than adapting your workflow to somebody else's collection of presets.

CapyBro also offers a local history of recent edits and an optional diff preview. The diff feature is worth using when you're editing something important because AI has an annoying habit of "fixing" sentences that weren't broken. Seeing the changes before accepting them can save you from discovering later that your carefully worded sentence now says something slightly different.

How to Use CapyBro

After installing CapyBro, configure an AI provider. For cloud processing, that means supplying your OpenRouter API key and selecting a model. For local processing, you'll need Ollama installed and a compatible model available.

Once that's done, the basic workflow is pleasantly short.

The hotkey is what makes the program useful. After using it a few times, reaching for Ctrl+Shift+E is considerably easier than bouncing back and forth between whatever you're writing and an AI browser tab.

Privacy and API Keys

CapyBro stores its settings locally and encrypts API keys using Windows security features. It also includes options for masking potentially sensitive information before sending text to an online AI provider.

That matters because it's easy to forget what you've selected. An email may contain names, phone numbers, addresses, account information, or other details you wouldn't intentionally paste into an online AI service.

For genuinely confidential material, using Ollama locally is the better option. Just remember that local processing only provides that privacy advantage when you're actually using a local model. Selecting a cloud provider means your text has to leave the PC to be processed.

The free edition is open source under the MIT license, which is another plus for anyone who wants to see what the software is doing rather than simply trusting a black box.

Is CapyBro Good for Code?

CapyBro can work with C++, Python, JavaScript, and other programming languages by sending your selected code to the AI model you've configured. How well it explains, fixes, or rewrites code depends mostly on the model you choose through OpenRouter or Ollama, rather than CapyBro itself.

It's especially handy when you're already working in a code editor. Select a chunk of code, an error message, comments, or documentation, hit the CapyBro hotkey, and ask the AI to explain what's wrong, clean it up, or suggest a fix without bouncing back and forth to a browser.

In that way, I think it is a great add-on for your IDE,

What Do You Get With CapyBro Pro?

The free version has everything most people need, but a one-time $9 Pro upgrade adds some useful power-user features. You get about 50 ready-made prompts covering Code Review, Legal, Marketing, Academic, and Business tasks, plus history export, settings backup, usage statistics, a custom one-off prompt box, and a hotkey for quickly switching between your favorite AI models.

There's no subscription, and the core text rewriting features, OpenRouter and Ollama support, and unlimited custom prompts are still available in the free version. Frankly, this is a great model where instead of locking features that you need, you actually get something useful for life at a fair price.

Limitations and Downsides

CapyBro is Windows-only, so there's not much here for Mac or Linux users.

Cloud models also require your own API access, which adds another account, API key, and potentially usage charges. Beginners who expect to install the program and immediately get unlimited free GPT-style processing may find that part confusing.

Local Ollama models remove the cloud requirement but introduce another problem: hardware. Smaller models can run on fairly ordinary PCs, but model size, RAM, GPU memory, and CPU performance all affect how quickly you get a response.

And AI rewriting still needs supervision. CapyBro makes getting the result faster, but it doesn't make AI incapable of confidently rewriting something into nonsense. Use the preview when the wording matters.

Geek Verdict

CapyBro solves one of the more irritating parts of using AI for everyday writing: constantly copying text into and out of a browser. Select your text, hit Ctrl+Shift+E, fix it, and get back to what you were doing.

We especially like it for spelling and grammar cleanup, quick rewrites, and users with dyslexia who want to concentrate on getting their thoughts onto the screen instead of wrestling with every typo. OpenRouter support makes it easy to use cloud models, while Ollama gives geeks the option of keeping the whole process local.

The setup is a little more involved than an all-in-one commercial AI assistant, and local models need appropriate hardware. Those are fair tradeoffs for a free, open-source Windows utility that lets you choose how and where your text gets processed.

Weird name, useful program, cool capybara logo. Works for us. This ones a keeper.