The file or text can stay local
The normal tool workflow runs in the browser using client-side JavaScript. The page itself is loaded from the website, but selected files and pasted content are not sent to a Privacy Toolbox processing API.
The website still loads over the network
HTML, CSS, JavaScript, icons, and hosting requests still use the network. A local-processing claim describes the selected input workflow, not the entire internet connection.
You can verify behavior
Use browser developer tools and synthetic test data to inspect network requests while running a tool. The test value should not appear in request URLs, headers, or bodies.
Local does not mean perfect
Local processing does not guarantee trustworthy code, complete anonymization, malware safety, legal compliance, or secure sharing after the result leaves the browser.