ShareSafe Local only
Verify “local only”

How ShareSafe keeps your files on your device

Files are read and processed in your browser tab. The page has no upload endpoint, and its Content Security Policy tells the browser to block every network connection the page might try to make.

What the page does with your data

Uploads your filesNo. There is no server endpoint to send them to; files are read with the browser’s File API.
Where processing runsIn a Web Worker inside this browser tab.
Analytics, ads, session recording, error reportingNone.
Remote AI or other APIsNone.
StorageMemory only. Nothing in localStorage, IndexedDB or service-worker caches; a refresh starts a new task.
Values in URLsNever. File contents, names and mappings are not put in URLs.
Console loggingNone. The lint rules forbid console calls in the code.

Verify it yourself

  1. Watch the network. Open the tool, open your browser’s developer tools and select the Network tab. Try the example and download the ZIP: after the page has loaded, no requests appear.
  2. Go offline. Once the page has loaded, disconnect from the network. Importing, processing and downloading keep working.
  3. Read the policy. The policy on the right is in the page source as a Content-Security-Policy meta tag. connect-src 'none' makes the browser refuse fetch, XHR, WebSocket and beacon requests, so file contents cannot be sent anywhere even by mistake.
default-src 'self';
script-src 'self';
worker-src 'self';
style-src 'self';
img-src 'self' data:;
font-src 'self';
connect-src 'none';
object-src 'none';
base-uri 'none';
form-action 'none'

From import to download

  1. Import. Files you drop or choose are checked against the limits (10 files, 10.0 MB each, 30.0 MB in total) before they are read, then decoded as UTF-8 in the tab.
  2. Process. Parsing, detection and replacement run in a Web Worker. The worker script is loaded with the page, so processing needs no further network requests.
  3. Download. Outputs are offered as blob: URLs created in the tab. By default they get neutral names (file_001.json…), because original file names can contain sensitive details. The optional report contains counts, formats and check results — never original values, mappings or file names.
  4. Clear. Clear task stops any running job, drops files, rules, mappings and previews, and revokes the download URLs. Closing or refreshing the tab discards everything as well.

What this does not protect against

  • Browser extensions with access to all sites can read any page, including this one. Use a profile without extensions for very sensitive files.
  • Releasing memory lets the browser reclaim it; it is not secure erasure. Files you downloaded stay on your disk.
  • Replacing selected values does not make a file anonymous. Suggestions are hints, not a complete scan, and ShareSafe never labels output as “safe to share”. Review the output before you send it.
  • The policy applies to the production site. A local development server runs without it.

Last reviewed .