NICH is a free Chrome browser extension for protecting privacy in AI conversations. It can replace names, email addresses, phone numbers, and other personal details in your messages with placeholders (such as [NAME 1] or [EMAIL 1]) before you send them to ChatGPT, Claude, Gemini, Perplexity, DeepSeek, or any other in-browser AI assistant. The AI only sees the placeholders, but the meaning of the text remains unchanged, so the answers are still useful. Each detail keeps the same placeholder throughout the entire message. When copying an answer, you can right-click and select "Copy Deanonymized" to restore the placeholders to the original real names, dates, or contact details. The entire process runs completely in the browser, and no data leaves your computer.
Main Capabilities
NICH can identify and replace a variety of sensitive information, including: personal names, company names, locations and addresses, email addresses, phone numbers, dates and times, amounts, card numbers, website addresses (URLs), and more. It combines a context-aware language model with precise rules, so it can find names it has never seen before while accurately identifying information with fixed formats such as emails, phone numbers, and card numbers. You can also customize terms, such as project code names or client names, and choose placeholders for them, all managed through the NICH icon in the toolbar.
How to Use
- Click the NICH button: when you click in a text box, a small black button with a slashed eye appears in the corner. Click it, and every personal detail in the box turns into a placeholder, such as [NAME 1] or [EMAIL 1].
- Send the message as usual: the AI only sees the placeholders, but the meaning of the text remains unchanged, so the answers are equally useful. Each detail keeps the same placeholder throughout the entire message.
- Copy an answer with restored information: select the answer and right-click to choose "Copy Deanonymized." When pasted into an email, document, or chat, every placeholder turns back into the original name, date, or contact details.
Use Cases
NICH is especially suitable for users who need to handle other people's data, such as: people who use AI to write emails, customer support teams, doctors and clinics, lawyers and contract processing, HR and recruiting, and anyone with a customer list. It also works with webmail and other web applications, because the button appears whenever you click into a text box.
Privacy and Local Processing
The detection model runs locally in Chrome. It downloads once the first time,and then is stored in the browser cache. There is no server, no account, no usage counter, no analytics. No one other than NICH itself and you can see your text. The only download is to get the model itself from Hugging Face.
Limitations
Currently only English is supported; other languages are not yet supported. The model is not perfect and may fail to find all names and locations, so it is recommended to quickly check the masked text before sending. The first use takes some time to download the model, and after that it is fast.
Pricing and Support
NICH is free, with no limits, no account, and no paid tier. If you find it saves you time, you can support the project with a small donation. If you have other questions, you can contact us by email at anonymizer@nichtech.uk.
