What Is an AI Overlay?
The New Way to Use AI Without Switching Tabs
You shouldn't have to leave what you're working on to use AI. An AI overlay brings the AI to you, right on top of your screen, in every app.
Updated September 13, 2026
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What Is an AI Overlay?
An AI overlay is a desktop application that sits on top of your entire screen. It lets you interact with artificial intelligence from any app, on any window, without ever switching tabs or copying and pasting text into a chat box.
Think of it like a transparent layer of intelligence over everything you see. You press a keyboard shortcut, drag a box around anything visible on your screen, and the AI processes it instantly. The response appears in a small floating popup right where you're working.
It doesn't matter what app you're in. A PDF viewer, a coding editor, a video call, a textbook scan, an email thread, a design tool. The AI overlay reads whatever is on your screen and gives you an answer without interrupting your flow.
How It Works
The entire interaction takes about three seconds. Here's the full cycle:
- 1
Press your hotkey
A global keyboard shortcut (like Ctrl+1) activates the AI overlay from any app. Your screen dims slightly to indicate you're in selection mode.
- 2
Drag over anything
Click and drag a rectangle around what you want the AI to look at. Text, images, charts, code, handwriting, memes. If it's on your screen, it's readable.
- 3
AI processes your selection
The selected region is captured as an image and sent to an AI model. Depending on the overlay engine, this could be a vision model that reads images directly, an OCR engine that extracts text first, or a smart combination of both.
- 4
Get your answer
A floating popup appears with the AI's response. It stays on top of everything so you can read it while continuing your work. Copy it, dismiss it, or hit the hotkey again for a new query.
The overlay never takes focus from your current app. You don't switch windows. You don't open a browser. The AI comes to you.
The Old Way vs. an AI Overlay
Most people still use AI through a browser tab. That means every single interaction goes like this:
The ChatGPT workflow
- 1. See something you need help with
- 2. Open your browser
- 3. Navigate to ChatGPT
- 4. Take a screenshot or copy text
- 5. Paste it in and type your question
- 6. Wait for the response
- 7. Switch back to your original app
The AI overlay workflow
- 1. Press a hotkey
- 2. Drag over what you need
- 3. Read your answer
That's it. Three steps. You never leave your app.
Every trip to a browser tab breaks your focus. Research shows it takes an average of 23 minutes to fully refocus after a context switch. An AI overlay eliminates that entirely. The AI lives where you work, not in a separate window.
What Can an AI Overlay Read?
Anything visible on your screen. Seriously. If you can see it, the AI overlay can read it. Here's what that includes:
Text in any app including Word, Google Docs, Notion, Slack, Discord, and email clients
Code in VS Code, IntelliJ, Xcode, terminals, and any IDE
PDFs and scanned documents that you can't select or copy from
Images, charts, and diagrams including graphs, flowcharts, and infographics
Videos including paused frames, subtitles, or anything currently displaying
Math equations whether typed, rendered in LaTeX, or handwritten
Handwritten notes from tablet screenshots, photos of whiteboards, or scanned paper
Foreign language text from websites, apps, or images in any script
The reason this works is that the AI overlay captures the region as a screenshot and processes it with a vision model. It doesn't need to "select" text. It reads pixels. So even content inside images, videos, or apps that block text selection is completely readable.
Five Core Modes + Custom Prompt
A good AI overlay isn't just a question box. It gives you different ways to interact with what's on your screen. LowLighter has five core modes, while Pro adds Custom Prompt for a saved instruction tailored to your workflow:
Answer
Ask the AI anything about your selection. "What is this error?" "Solve this equation." "What does this chart show?" It gives you a direct, concise answer.
Explain
Breaks down complex content step by step. Drag over a math problem, a code block, a scientific diagram, or a dense paragraph, and the AI walks you through it like a tutor.
Summarize
Condenses long content into a few bullet points. Great for articles, documentation, research papers, or long email threads you don't want to read in full.
Translate
Translates any text on screen into 35+ languages. Works on websites, documents, images, and apps in any language, including ones with non-Latin scripts like Chinese, Arabic, Japanese, and Korean.
Rewrite
Takes your text and rewrites it for clarity, grammar, and flow. Ideal for cleaning up drafts, emails, essays, or messages before sending.
Custom Prompt
Applies your saved instruction to the selected content, so you can define your own task, format, tone, or point of view.
Each mode is bound to its own hotkey. So you can assign Ctrl+1 to Answer, Ctrl+2 to Explain, and so on. One keypress and you're in the right mode, ready to drag.
Beyond a Quick Answer
LowLighter v3 includes three ways to get help. Choose the one that matches the amount of work you want completed.
Screen answers
Select visible content and ask for an answer, summary, translation, rewrite, explanation, or saved custom prompt. The answer box stays close to the source application.
Agent
Give Agent a longer task across websites, documents, files, code, or desktop applications. It can draft a Google Doc, build a presentation, organize a spreadsheet, or work with a DOCX or PDF while showing its progress.
Meetings
Start a live transcription session, choose a meeting mode, add screen context or reference files, and ask Assist for help during the conversation.
The answer box, Agent, Meetings, and visual overlays are designed to remain available after you close the main LowLighter window. Open LowLighter again from the Windows system tray or macOS menu bar. Choose Quit when you want all running LowLighter features to stop.
These desktop surfaces remain interactive while the application you are using stays available. The answer surface is built entirely in native Rust. The visible Agent and Meetings overlays use Swift on macOS and C# on Windows.
Who Uses an AI Overlay?
Students
Drag over a textbook page, a lecture slide, a homework problem, or any study material and get an instant explanation. No need to type the question. No need to describe the image. Just highlight and learn. The Explain mode is particularly powerful for step by step breakdowns of math, science, and code.
Developers
Highlight an error message, a stack trace, a piece of unfamiliar code, or documentation you can't parse, and get an immediate answer. It works inside VS Code, terminals, browser dev tools, and literally any editor. Faster than opening a new tab to search Stack Overflow.
Professionals
Summarize long email threads, rewrite messages for clarity, translate documents for international clients, or get quick explanations of charts in reports. All without leaving Outlook, Slack, or whatever tool you're already in.
Researchers
Quickly parse academic papers, extract key points from dense text, translate foreign language sources, and analyze data visualizations. The AI overlay reads PDFs and scanned documents that you can't select text from.
Language Learners
Drag over any foreign text on screen and get an instant translation. Works on websites, apps, subtitles, and images. Supports 35+ languages including Chinese, Japanese, Korean, Arabic, Hindi, and every major European language.
Phantom Mode: The Invisible AI Overlay
Phantom Mode makes the entire overlay invisible to screen recordings, screen shares, and screenshot tools.
How? On both Windows and macOS, Phantom Mode makes the window completely invisible to every capture tool. You see it on your screen. Anyone watching your screen share or recording sees nothing.
This isn't a hack or a workaround. Phantom Mode also includes private text delivery (typing responses directly into your text field) and private hotkeys that work in any environment.
Frequently Asked Questions
What is an AI overlay?
An AI overlay is a desktop application that sits on top of your entire screen, allowing you to interact with artificial intelligence from any app without switching tabs or windows. You highlight content on screen, and the AI processes it instantly in a floating popup.
How is an AI overlay different from ChatGPT?
ChatGPT lives in a browser tab. You have to switch to it, paste your content, wait for a response, then switch back. An AI overlay works directly on top of whatever you're doing. You press a hotkey, drag over anything on screen, and get an answer without ever leaving your current app.
Can an AI overlay read images and screenshots?
Yes. Modern AI overlays use vision models that can read images, screenshots, diagrams, charts, handwritten notes, code, PDFs, and anything else visible on your screen. They capture the region as a screenshot and process the pixels directly, so they're not limited to selectable text.
What can you use an AI overlay for?
AI overlays can answer questions about anything on screen, explain complex content step by step, summarize long articles, translate text into 35+ languages, and rewrite content for clarity. They work on PDFs, videos, code editors, emails, Slack messages, and any other app.
Is my screen content stored or saved?
No. With LowLighter, selected regions are processed in real time and discarded immediately. Your screen content is never stored, logged, or used for training. See the Privacy Policy for full details.
Does it work on Mac and Windows?
Yes. LowLighter runs natively on macOS (Apple Silicon and Intel) and Windows 10/11. It's a native desktop app, not a browser extension.
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LowLighter is your invisible universal AI overlay. It works on macOS and Windows and gives you 15 free answers every day with Answer and Summarize modes, no credit card needed.