Select text.
Press a key.
Understand it.
Highlight a word, a sentence or a block of code in any app. A small panel opens right at your cursor with a clear explanation, then gets out of your way.
Explain This
Three steps. No window switching.
Explain This never takes over your screen. The panel appears beside your cursor and your app stays exactly where it was.
Select text
A term, a sentence, a function, a paragraph in another language. Any app that lets you highlight it.
Press the hotkey
That is the default. Record any combination you like in Settings.
Read, copy, close
A one-line summary first, detail below. Copy it, try again, or press esc to dismiss.
Bring your own AI.
Choose the provider you already use, paste your key, and set any model ID it supports. Switching providers keeps each key and model saved.
- Google Gemini · fast default
- OpenRouter · hundreds of models, one key
- Vercel AI Gateway · route through your gateway
You pay your provider directly for what you use. We never see your key or your text.
Your text goes one place: your provider.
Requests travel straight from your Mac to the provider you chose. There is no Explain This server in between.
Keys in Keychain
API keys live in the macOS Keychain, never in plain files.
Clipboard restored
Capturing a selection briefly uses Copy, then puts back whatever you had copied.
No tracking
No analytics in the app or on this site. Read the privacy policy.
Questions, answered.
The basics before you buy. For troubleshooting, see Support.
What does Explain This do?
Select text in almost any Mac app, press a hotkey (⌘⇧E by default), and a small panel opens at your cursor with a plain-language explanation. It works for words, sentences, code and text in other languages.
How much does it cost?
A one-time $5 purchase on Gumroad, with no subscription and updates included. The AI itself is billed separately by the provider you choose, because you use your own API key.
Why do I need my own API key?
Explain This has no servers of its own. Your text goes straight from your Mac to the provider you pick (Google Gemini, OpenRouter or Vercel AI Gateway), and that provider bills you directly for what you use. Short explanations typically use very little, and some providers offer a free tier. Check your provider's current pricing.
Where do I get a key, and which model should I use?
Create a key in your provider's dashboard, then open Settings → AI Provider, paste it and press Verify. Gemini starts on gemini-2.5-flash, a fast and inexpensive default. On OpenRouter or Vercel AI Gateway you can type any model ID the service supports. Each provider keeps its own key and model, so you can switch back and forth freely.
Where does my text go? Is it private?
Only to the provider you chose, over a direct connection from your Mac. There is no Explain This server in between, and there are no analytics in the app or on this site. API keys are stored in the macOS Keychain. Your provider has its own data policy, so review it for anything sensitive. See the privacy policy.
Why does it ask for Accessibility permission?
To read your selection, Explain This briefly triggers Copy (⌘C) in the app you are using. macOS only allows that with Accessibility access. Your previous clipboard contents are restored right afterwards. Grant it in System Settings → Privacy & Security → Accessibility.
Which apps does it work in?
Any app where you can select text and copy it: browsers, mail, PDFs, notes, code editors, chat apps and more. If an app blocks selection or copying, the panel shows “No text selected”.
Can I change the hotkey?
Yes. Open Settings → General and record any key combination you like. Press esc to close the panel.
How do updates work?
The app can check for updates automatically and install them in place. You can turn this off or check manually in Settings. Updates are included in your purchase.
Is there a Mac App Store version?
Not yet. For now Explain This is sold directly through Gumroad. This page and the Versions page will be updated if that changes.
Something isn't working. Where do I get help?
Start with the Support page, which covers the hotkey not responding and common provider errors. For refunds, use Gumroad's own refund process.