What browser-local subtitle processing protects, and what it does not
Distinguish file processing from loading a website, exporting a report and future advertising integrations.
The file stays with this browser tab
The four subtitle tools read an uploaded text file through the browser's file interface or use text pasted into the editor. Parsing, checking, retiming, comparison and conversion run on the device. The tool code does not send the subtitle contents to a server, a transcription provider or an AI API.
Output downloads are generated from browser memory. Refreshing or closing the tab clears the working state; the application does not save the subtitle in localStorage. Keep a copy of any output you need before leaving the page.
Loading a website is still a network event
The browser contacts the hosting service to retrieve the page and its assets. Hosting providers can receive ordinary request information such as IP address, requested path and browser details. Browser-local file handling does not make that initial visit anonymous.
The first release contains no advertising runtime, analytics script or external font. If advertising or analytics is added later, the privacy page and any required consent controls must be updated to describe the actual integration before activation.
A report can be sensitive too
The report is downloaded by you rather than sent by this tool. Diagnostic findings can include cue numbers, source lines and timing information. Operation reports can describe changes. Check the report before forwarding it to another person, especially for confidential client work.
Do not paste passwords, access keys or unrelated personal data into a subtitle editor. Local processing cannot protect a device that already has untrusted extensions, malware, screen sharing or another user with access to the browser.
Verify the claim for your workflow
A reproducible browser check should exercise the tools with a harmless fixture and confirm that no file contents are posted, uploaded or included in a URL. The release's own tests include this network boundary alongside functional inputs. They support this version's behavior, not a promise about every future feature.