It's tax season. Right now, millions of people are uploading W-2s, 1099s and full tax returns into ChatGPT to help them understand their filing, find deductions or draft questions for their accountant. A single tax return has your Social Security number, your employer's name and address, your income, your bank routing number for direct deposit, your spouse's information and your dependents' names. All on one document. That's everything someone would need to open a credit card in your name, file a fraudulent tax return, or access your bank account.
Last week, Andy Sambandam, founder of a privacy tech firm, warned: "Don't upload your tax return to AI." His reason: once it's there, it's nearly impossible to get back out. Reddit's r/tax and r/personalfinance are full of people doing it anyway. They're not being reckless. They just want help with something complicated, and the AI is right there.
Tax returns are the densest example, but the pattern is everywhere. A parent pastes their kid's progress report into Claude, and the report has the child's full name, student ID and learning accommodations, the kind of information that's protected by federal law and could follow a child for years if exposed. A freelancer copies a client contract into Gemini with the client's legal name and payment terms, the kind of detail that could cost them the client and violate their NDA. Nobody reads every line before they hit enter.
Once it leaves your device, you lose control
That data enters a seven-stage pipeline most people never think about. It gets stored on company servers for 30 days to five years depending on the platform. It can be read by human reviewers. It may train a future model, and researchers have proven that models can memorize and regurgitate training data verbatim. It can be subpoenaed by law enforcement or locked forever by court order (a federal judge did exactly that to millions of ChatGPT conversations in the New York Times lawsuit). And if you accessed the AI through a third-party app, that app stores your data under its own rules: one popular wrapper app left 300 million messages in an unprotected database.
All of that data can also be breached. There were over 3,100 data breaches in the U.S. in 2024 alone, affecting 1.7 billion people. Companies of every size get hit. The 2017 Equifax hack exposed 147 million Social Security numbers. The 2015 Ashley Madison breach leaked names and home addresses. Those were devastating. But an AI chat breach would expose something no previous breach ever could: what people actually think. Medical fears in their own words. Legal problems with real names and dollar amounts. Career doubts, relationship crises and financial secrets, all volunteered freely to what felt like a private conversation. No breach in history has ever had that kind of depth.
You can opt out of training on every platform, and you should. But opting out controls what happens after the data lands on their servers. It doesn't stop you from sending it. The Social Security number on that tax return, the student ID on that progress report, the payment terms in that contract: once they leave your device, they're gone. The only fix that works is catching sensitive data before it leaves.
That's why we built BeatMask
Today we're launching two products. Both catch sensitive data before it gets shared by mistake. Both run entirely on your machine.
BeatMask Free is a Chrome extension. It scans what you type, paste and upload into AI applications before anything gets transmitted. ChatGPT, Claude, Gemini, Copilot, DeepSeek, Perplexity: if you're sending it to an AI, BeatMask Free is watching. It catches API keys, passwords, Social Security numbers, credit card numbers, phone numbers, medical terminology and more. Over 330 detection patterns, all running locally.
When it catches a high-severity match, it masks the value automatically. For everything else, you get a single-click choice. Either way, the AI still gets the context it needs. It just doesn't get the real data.
BeatMask Pro is a macOS desktop app. It works alongside the extension but goes further, monitoring sensitive data moving through your clipboard, files and apps across your entire Mac. And it adds deeper, context-aware detection powered by a local AI language model, bringing the total to over 500 patterns and catching sensitive information even when it's buried in longer text or doesn't follow a simple format. Everything still runs on your machine. No servers, no syncing, no external connections of any kind.
BeatMask Free protects your browser. BeatMask Pro protects your entire device.
Nothing leaves your device. You can verify that yourself.
Historically, tools that try to catch data leakage have worked the same way: route everything through a cloud for analysis. Enterprise DLP, email scanners, compliance filters. If the tool that's supposed to guard your data ships it to a second cloud, you've just added another company to the list of places it lives.
Other browser tools haven't earned much trust either. In December 2025, researchers found that four popular Chrome extensions (including one with Google's "Featured" badge) were quietly intercepting AI conversations from over seven million users and transmitting them to a data broker. A separate Incogni analysis of 442 AI-powered extensions found that over half collect user data.
BeatMask runs entirely on your device. No cloud servers. No accounts. No telemetry. We can't see your prompts, your detections or your masked values. Not because we promise not to, but because the code makes it impossible. Open your browser's dev tools, watch the network tab, see nothing leave.
Available now
BeatMask Free is available now on Chrome. BeatMask Pro is available on macOS. Edge and Windows support are coming soon.
Try the interactive demo on the homepage, and you can be up and running in under ten seconds.
The data never leaves your device. You can verify that yourself. We designed it that way.