I keep hearing the same question from people evaluating WindowSill: "Why would I use this when I can just type my prompt in ChatGPT?"
It's a fair question. Both tools use AI. Both can improve your writing. But they solve completely different problems, and confusing them leads to picking the wrong tool for the job. It's a bit like asking why you'd use a spell checker when you could hire an editor. Sure, the editor can do more. But you don't need an editor every time you send a Teams message.
This article breaks down what each tool actually does, where they overlap, and when you should reach for one over the other.
The short answer
ChatGPT, Claude, and Perplexity are AI chatbots. You open a conversation, describe what you want, and get a response. They're built for back-and-forth dialogue: brainstorming, research, generating content from scratch, answering questions.
WindowSill is a desktop command bar for Windows. It's a productivity toolbar that bundles clipboard history, media controls, a calendar with world clocks, reminders, a unit converter, image tools, and more into one bar at the edge of your screen. One of those tools is AI-powered text actions: you select text in any app, and WindowSill rewrites it, fixes the grammar, translates it, or changes the tone, right where you're working. There's no chat window. No conversation. No copy-pasting between tabs.
They're different categories of software that happen to share the same underlying technology.
What a chatbot is good at
ChatGPT and its peers shine when you need to generate something from nothing. You want a first draft of a blog post? Ask ChatGPT. You need to brainstorm product names? Start a conversation. You want to understand a complex topic? Have a back-and-forth until it clicks.
Chatbots are also great at tasks that require context-building over multiple messages. "Here's my company background, here's my audience, now write me three email subject lines" works well because the chatbot remembers the whole conversation.
I won't pretend WindowSill can do any of that. It can't. There's no chat interface because chat isn't the problem I built it to solve.
What a chatbot is bad at
Here's where things get interesting. Think about the last ten times you used ChatGPT for writing help. How many of those were "write me something from scratch" versus "fix this thing I already wrote"?
For a lot of people, the honest answer is that they spend most of their time on the second one. They draft an email in Outlook, realize it sounds too blunt, copy the text, switch to ChatGPT, paste it, type "make this more professional," copy the result, switch back to Outlook, paste it over the original, and re-read it to make sure nothing weird happened.
That's seven steps for a task that should take one.
And that's the specific problem WindowSill solves. You select the text in Outlook (or Slack, or Word, or Notion, or any other app), click "Change Tone" in the command bar, and the updated text replaces your selection. Done. You never leave the app you're working in.
The copy-paste tax
Every time you switch to a chatbot to fix existing text, you pay a small tax:
- Context switching. You leave whatever you're doing, open a browser tab, and mentally shift into "prompt engineering" mode.
- Manual transfer. Copy the text, paste it, write your instruction, copy the result, paste it back.
- Verification overhead. Chatbots sometimes change things you didn't ask them to change. They might rewrite your whole paragraph when you only wanted a grammar fix. You have to diff the result against your original.
- Lost formatting. Paste into ChatGPT, and your bullet points, bold text, and links often don't survive the round trip.
One round of this takes maybe 30 seconds. But if you do it twenty times a day, that's ten minutes of daily friction. More importantly, it's twenty interruptions to your focus.
How WindowSill works differently
WindowSill sits at the edge of your screen as a thin command bar. When you select text anywhere on your system, it detects the selection and shows relevant actions: fix grammar, rewrite, translate, change tone, or run a custom prompt you've saved.
You pick an action. The AI processes your text. The result replaces your selection in the app you're already using. That's it.
There's no conversation to manage. No prompt to craft. No copy-paste. The interaction model is closer to a spell checker than a chatbot: select, fix, move on.
Custom prompts for repeated tasks
If you find yourself asking ChatGPT the same thing over and over ("summarize this in three bullet points," "rewrite this for a non-technical audience," "extract the action items from this meeting transcript"), you can save those instructions as custom prompts in WindowSill. After that, it's a single click on any selected text. No typing required.
For teams, admins can create and distribute shared prompts across the organization, so everyone has access to the same standardized text actions.
Bring your own AI provider
WindowSill isn't locked to one AI model. You can connect OpenAI, Anthropic, Google, or run a local model through Ollama for complete privacy. If your company has an existing OpenAI contract, you can use that same API key. If data can't leave your network, run everything locally.
This matters for enterprise teams that have compliance requirements around where data is processed. ChatGPT sends everything to OpenAI's servers. WindowSill lets you choose.
A side-by-side comparison
| ChatGPT / Claude / Perplexity | WindowSill | |
|---|---|---|
| What it is | AI chatbot in a browser | Desktop command bar for Windows |
| Best for | Generating content from scratch, research, brainstorming, multi-turn conversations | Desktop productivity toolkit: AI text actions, clipboard, media, calendar, and more |
| Interaction model | Type prompts, read responses, iterate | Select text in any app, pick an action, done |
| Where it works | Browser tab (or desktop app) | Any app on your Windows desktop |
| Copy-paste needed? | Yes, to get text in and results back out | No, it reads and replaces your selection directly |
| Chat / conversation | Yes, full multi-turn dialogue | No, single-action text transformations |
| AI provider | Fixed (OpenAI, Anthropic, etc.) | Your choice: OpenAI, Anthropic, Google, local models |
| Data control | Sent to provider's servers | Your choice, including fully local processing |
| Extra features | Web search, image generation, code interpreter | Clipboard history, media control, reminders, calendar with world clocks, image tools, unit converter, extensions, and more |
When to use ChatGPT
Use a chatbot when you need to:
- Generate content from scratch. "Write a job description for a senior developer." WindowSill can't do this because there's no existing text to work with.
- Have a multi-turn conversation. "Here's my resume. Now tailor this cover letter to match this job posting." The back-and-forth is the value.
- Research and explore. "Explain the pros and cons of microservices for a 10-person team." You're learning, not editing.
- Process long documents with follow-up questions. "Summarize this 20-page report. Now focus on section 3. What are the risks?"
When to use WindowSill
The AI text features are the ones that trigger the comparison with ChatGPT, but they're only one slice of what WindowSill does. The app is a productivity toolbar that sits at the edge of your screen and gives you quick access to a growing set of tools:
- AI text actions. Fix grammar, change tone, translate, rewrite, or run custom prompts on selected text in any app.
- Clipboard history. Everything you've copied today, searchable and one click away. Supports text, images, URLs, and colors. Passwords are auto-hidden.
- Media control. Skip tracks, pause, adjust volume without switching windows. Works with Spotify, YouTube, Apple Music, and most media players.
- Calendar and world clocks. See your calendar, upcoming meetings, and multiple time zones at a glance, right from the bar.
- Short-term reminders. Set a quick reminder and get a full-screen alert when it's time. Helpful for anyone (especially ADHD users) who needs unmissable nudges.
- Unit and currency converter. Select "15 miles" in any app and see the kilometer equivalent instantly. Currency rates update daily.
- Image and video tools. Resize, compress, or convert files right from File Explorer. Batch processing included.
- URL shortener and QR codes. Select a URL, shorten it, or turn it into a QR code.
- Quick notes. Jot something down without opening a separate app.
- App launcher, Pomodoro timer, performance counters, inline terminal, calendar, and more through community-built extensions.
The AI features require a WindowSill+ or Pro subscription. Everything else is free, forever.
So when you compare WindowSill to ChatGPT, you're really comparing a general-purpose chatbot to a full desktop productivity toolkit that happens to include AI. That's not a knock on ChatGPT. It's just a different product category.
They work well together
This isn't an either/or choice. The two tools cover different ground.
You might use ChatGPT to draft a project proposal from scratch, then use WindowSill throughout the day to polish individual emails about that proposal, translate a summary for a colleague in another country, glance at a coworker's time zone before scheduling a call, paste a link you copied three hours ago, or convert a measurement from a spec sheet.
The chatbot handles creation and conversation. The command bar handles everything you do between those moments.
A note for IT teams evaluating WindowSill
If you're considering WindowSill for your organization, the comparison with ChatGPT probably comes up in internal discussions. Here's how I'd frame it for a buying decision:
ChatGPT licenses give your team a general-purpose AI assistant. That's valuable for many workflows, but each interaction requires a user to open the chatbot, construct a prompt, and transfer text manually.
WindowSill Pro gives your team one-click text actions that work inside every app they already use. Admins can manage prompts centrally, control which AI providers are allowed, and deploy through standard tools like Intune or SCCM. Users don't need to learn prompt engineering. They select text, pick an action, and keep working.
The real question isn't "ChatGPT or WindowSill." It's "do our employees spend time copy-pasting text into chatbots to fix grammar, translate, or rewrite things?" If yes, WindowSill removes that friction.
Frequently Asked Questions
Can WindowSill replace ChatGPT?
No. WindowSill doesn't generate content from scratch and doesn't support multi-turn conversations. It's designed for quick text transformations on existing content: grammar fixes, rewrites, translations, and tone changes. If you need to brainstorm, research, or create content from a blank page, you still need a chatbot.
Can I chat with the AI in WindowSill?
No, and that's by design. WindowSill uses a "select and act" model rather than a conversation model. You select text in any app, choose an action, and get the result. This makes each interaction faster but means WindowSill isn't suited for back-and-forth dialogue.
Does WindowSill use the same AI models as ChatGPT?
It can. WindowSill supports multiple AI providers, including OpenAI (the same company behind ChatGPT), Anthropic (Claude), Google, and local models via Ollama. You choose which provider and model to use based on your needs, budget, or privacy requirements.
Is WindowSill free?
The core productivity features (clipboard history, media control, reminders, and more) are free forever. The AI text features require a WindowSill+ subscription. Teams can use WindowSill Pro for centralized management and enterprise deployment options.
Does WindowSill work on Mac or mobile?
No. WindowSill is a native Windows desktop application. It's built specifically for Windows and takes advantage of the platform in ways a cross-platform tool can't. If you need AI writing help on Mac or mobile, a chatbot or another tool is the better option there.