Privacy Policy — dejapanify

Last updated: 29 September 2026

The short version

dejapanify collects nothing, transmits nothing, and has no servers.

Everything the extension does happens locally in your browser. There is no analytics, no telemetry, no crash reporting, no account, and no network code of any kind in the extension.

What the extension accesses

To convert form input between half-width (半角) and full-width (全角), the extension reads and rewrites the values of form fields on pages you visit, along with the surrounding labels and attributes that indicate which character width a field requires.

This happens entirely in your browser's memory, at the moment you interact with the field. Field values are never stored, logged, or sent anywhere.

Some fields are never read or changed at all, whatever the page asks for: passwords, payment card details (number, security code, expiry date, card-holder name), and bank account, branch and institution numbers. The extension leaves them exactly as you typed them.

In number fields that hold money, such as a price, a budget or an annual income, it reads the amount you typed in order to add or remove thousands separators (5,000,000 or 5000000) to match the form. It never reads card numbers, security codes or bank account numbers.

Because it reads what you type into these fields, such as names, addresses, phone numbers, email addresses and amounts, some stores describe the extension as *handling* personal and financial information and website content. That handling is the on-device conversion described above and nothing more; none of it is collected.

What the extension stores

Only your own settings, kept in your browser's extension storage:

Which conversion types you have enabled
The confidence threshold
Whether the undo notice is shown
Lists of sites where you have enabled or disabled the extension

If your browser has extension sync turned on, your browser syncs these settings between your own devices using your browser account. That is your browser's sync, not ours — the extension author has no access to it and receives nothing.

You can erase all of it at any time by removing the extension, or with Reset to defaults on the settings page.

What is never collected

To be explicit, the extension does not collect, transmit or store:

Anything you type into forms
Page contents, URLs or browsing history
Personal or identifying information
IP addresses
Analytics or usage statistics of any kind

Permissions

Permission	Why
`storage`	Saves your settings, described above. Nothing else.
Content script on all sites	Japanese forms are not limited to one domain, so the extension cannot know in advance which pages have them. It takes no action unless a page looks Japanese and a field identifies the width it needs.

Third parties

There are none. The extension makes no network requests, loads no remote code, bundles no third-party analytics or advertising, and shares data with nobody — because it has no data to share.

Verifying this yourself

You don't have to take our word for it. The extension is open source under the MIT licence, and the published package is reproducible from that source:

Source: https://github.com/b1gmaw/dejapanify
Searching the source for fetch, XMLHttpRequest, WebSocket or

sendBeacon returns nothing. This is checked automatically: the test suite scans the built package for network primitives, so adding any would fail the build rather than quietly contradict this page.

Contact

Questions or concerns: https://github.com/b1gmaw/dejapanify/issues

Changes

If this policy ever changes, the updated version will be published at this address and the date above will change. Since the extension collects no data, no change can retroactively affect information already gathered.