Velum Lite

Mask PII before it reaches ChatGPT, Claude or any AI assistant, and restore it in the reply. 100% on-device, no internet. Velum Lite masks personal and sensitive data before you paste it into an AI assistant, then restores the originals in the reply. Everything runs on your machine. The extension makes no internet requests and bundles its detection model locally, so it works fully offline.

How it works

• Mask: paste text into the popup and it masks on the spot. A black bar sweeps

across each identifier, leaves a token behind, and the result lands on your clipboard. Paste that into the chatbot.

• Unmask: paste the reply back, press Unmask, and your originals are restored

from an in-memory mapping that never leaves the browser.

• Session mapping: see exactly what was taken out and what replaced it. Each

original stays under a bar until you lift it.

• Files: drop a document onto the popup and get a masked Markdown file back.

Common document, text and spreadsheet formats are supported, and optional offline OCR handles scanned PDFs.

• Side panel: dock Velum beside the tab instead of using a popup that closes

the moment you click away. Off by default, and the toolbar icon keeps opening the popup until you switch it on.

• Optional in-page mode: with a licence, turn on In-page masking to get a Mask

button in the composer on claude.ai, chatgpt.com and gemini.google.com. Off by default. Enabling it asks for permission for those three sites only, and nothing is requested without a licence.

Recently added

• The on-device detection model now starts reliably. A packaging bug in one

earlier build could leave the extension running pattern detection only.

• Clearer licensing: the extension never asks for site access it cannot use,

and the in-page Mask button appears only on licensed installs.

• The side panel, so Velum can stay open next to a long conversation.
• A first run page that masks a sample in your own browser, so you can watch

the extension work before trusting it with anything real. It also warms up the model, which makes your first real mask faster.

• Wider country coverage, and steadier detection in long documents.

What it detects

Contact and financial identifiers run always, in every language and country. That covers email addresses and phone numbers, bank account and payment card numbers, passport numbers, and the network and device identifiers that show up in logs and config files.

Credentials are matched by around fifty built-in patterns spanning cloud platforms, code hosting, package registries, payment processors, messaging services and AI providers, together with signed web tokens, private keys, database connection strings and other high-entropy secrets.

National identifiers are matched by country packs with checksum validation, so a number that fails its own check digit is left alone instead of masked. Packs ship today for Spain, the United States, the United Kingdom, France, Germany, Türkiye and Italy. Newer packs cover South Africa, Nigeria and Kenya. Each one also carries the address and phone recognisers for that country. The active set is detected from your browser language and can be changed in Settings.

People, organizations and places are found by a local multilingual model rather than a pattern, so unusual names are still caught. They become tokens by default, or format-valid surrogates if you opt in.

Settings

• Countries and regions: pick which national-identifier packs run, or leave it

on auto.

• Detection sensitivity: how sure the model has to be before it masks a name,

organization or place. Lower catches more and over-masks more.

• Realistic surrogates instead of tokens: replaces detected values with

format-valid fakes rather than opaque markers. Off by default, because a surrogate that reads as real is easy to forget to unmask.

• OCR scanned PDFs: runs offline OCR on image-only documents. Off by default;

it is slow and adds nothing unless you work with scans.

• Open in side panel: opens Velum in the browser side panel instead of the

popup. Off by default.

• Theme: follows your browser, or pin light or dark.
• Use Desktop engine: routes masking to the Velum Desktop app on the same

machine over the loopback interface. Off by default, and only loopback addresses are accepted.

Privacy

• 100% on device. No servers, no analytics, no accounts.
• The mapping that reverses masking lives in session memory and clears when the

browser closes.

• No host permissions are requested unless you turn on in-page masking.

Free and paid

• Masking and unmasking text in the popup is free, with no trial period and no

expiry. Full detection is included: national identifiers, credentials, and names, organizations and places through the local model.

• A licence unlocks masking documents and the in-page Mask button. Licences are

sold at velumprivacy.com and the same key also activates Velum Desktop.

• Unmasking is never restricted, licence or not. Anything you have masked, you

can always restore.

Worth knowing

• Detection is strong but not perfect. Read the masked text before you send it.
• Always unmask the reply before forwarding it, above all with realistic

surrogates turned on.