NordTime

Your browser's time zone, automatically matched to your VPN location.
A Manifest V3 extension for Chrome, Edge, Brave, Opera and other Chromium browsers.

---

When you connect to a VPN, websites see an IP address in another country, but your browser still reports your real time zone through JavaScript (Date, Intl.DateTimeFormat, …). That mismatch is one of the easiest ways for a site to tell that you are using a VPN.

NordTime fixes it. It checks the public IP address your browser is using, looks up where that IP is located, and makes every website see the time zone of that location. When the VPN switches servers, NordTime notices and follows automatically.

Features

• Fully automatic. Detects your public IP on startup, every minute (configurable), and right away when the network changes (VPN connect, disconnect or server switch).
• Applied before the page runs. The zone is in place before the first inline <script> on the page runs, so scripts that check early still see the spoofed zone.
• Live switching. Open tabs follow a new location immediately, without a reload.
• Thorough coverage. Date getters and setters, getTimezoneOffset, toString and friends, toLocale*String, the Date constructor and Date.parse for local-time strings, Intl.DateTimeFormat/resolvedOptions(), Temporal.Now, and same-origin iframes, including iframes that a page script creates and reads straight away.
• Hard to detect. Patched functions keep their native name, length and toString() output (function getHours() { [native code] }). Subclassing Date and instanceof still work.
• Correct daylight saving time. Offsets are computed per instant from the browser's own time zone data.
• Manual override. Pin any of the ~420 IANA time zones from a searchable list.
• Resilient lookups. Four geolocation providers with automatic fallback. The last known location is kept if all of them fail.
• Badge and notifications. The toolbar badge shows the current country code, and an optional desktop notification tells you when the zone changes.

Installation

From source (developer mode)

1. Download this repository (ZIP from Releases or git clone).
2. Open chrome://extensions (or edge://extensions).
3. Turn on Developer mode.
4. Click Load unpacked and select the NordTime folder (the one that contains manifest.json).
5. Pin NordTime to the toolbar. It starts working at once.

How it works

Step	What happens
1 · Get public IP	The service worker gets the public IP from ipify, Cloudflare or icanhazip. The request goes through the browser, so it shows the VPN exit IP, whether the VPN runs as a system app or as a browser proxy extension.
2 · Resolve time zone	The IP is turned into an IANA time zone by ipwho.is, geojs.io, ipapi.co or freeipapi.com, each one a fallback for the one before. The location is looked up again only when the IP changes, or every 6 hours.
3 · Publish active zone	chrome.storage is asynchronous and would lose the race against inline page scripts. Instead, NordTime registers its content scripts with a few one-line files (src/content/zone/bitN.js) that encode the zone's index in Intl.supportedValuesOf('timeZone'). The relay therefore knows the zone synchronously at document_start.
4 · inject.js	inject.js runs in the page's main world. It calculates wall-clock time in the target zone with Intl.DateTimeFormat#formatToParts and caches the results. All hooks fall back to native behavior when NordTime is disabled.

Privacy

• NordTime has no analytics and no servers of its own.
• The only network requests it makes are the IP and geolocation lookups listed above. They are sent without cookies or a referrer.
• Everything it stores (settings, last location) stays in chrome.storage.local on your device.
• Full details: Privacy Policy.

Permissions

Permission	Why
<all_urls> host access	Apply the time zone on every site and call the lookup APIs
scripting	Register the content scripts that carry the current zone
storage	Settings and last known location
alarms	Periodic IP check
webRequest	Notice network changes (ERR_NETWORK_CHANGED) when a VPN connects or disconnects
notifications	Optional "time zone changed" notification

Limitations

• Web Workers and Service Workers use the real system zone. JavaScript in the page itself, which is what nearly all sites check, is covered.
• Changing the time zone does not change other location signals, such as Accept-Language, WebRTC or geolocation. Use your VPN's own leak protection for those.
• Cross-origin iframes are covered by their own content-script instance, not by the parent page's hooks.

Development

npm install
npx playwright install chromium
npm test                    # end-to-end test in Chromium with the extension loaded
CHANNEL=msedge npm test     # run the tests in Microsoft Edge instead
npm run icons               # re-render icons/*.png from icons/icon.svg
npm run package             # build dist/nordtime-v<version>.zip

The end-to-end suite (tests/e2e.mjs) loads the unpacked extension and checks:

• real IP detection;
• more than 20 time zone behaviors each for Asia/Tokyo and America/New_York (including DST);
• live switching, and the disabled state;
• a simulated VPN server change (mocked IP that resolves to Tokyo).

Continuous integration and releases

GitHub Actions runs the end-to-end suite on every push and pull request. To publish a release, bump version in manifest.json, commit, then push a matching tag. The workflow runs the tests, builds the ZIP and attaches it to a GitHub release:

git tag v1.0.1
git push origin v1.0.1

Project layout

manifest.json
src/
  background.js        IP detection, geolocation, alarms, badge, content script registration
  content/inject.js    page-world time zone shim
  content/relay.js     isolated-world bridge (storage → page)
  content/zone/*.js    synchronous zone encoding (see "How it works")
  popup/               toolbar popup UI
icons/                 SVG source + PNG renders
tests/e2e.mjs          Playwright end-to-end tests

License

MIT. NordTime is an independent project. It is not affiliated with Nord Security or NordVPN. The color scheme is based on the open-source Nord palette.