Nocturne collects nothing, sends nothing, and contacts no server.

Last updated 31 July 2026. Applies to Nocturne Dark Mode for Firefox, Chrome and Edge.

WHAT IS COLLECTED

Nothing. There is no analytics, no telemetry, no crash reporting, no account, and no identifier of any kind.

WHAT LEAVES YOUR DEVICE

Nothing. Nocturne makes no network requests at all, in any mode, ever.

This is not a promise resting on good intentions. The build enforces it: if any networking primitive (fetch, XMLHttpRequest, sendBeacon, WebSocket, EventSource, importScripts) appears anywhere in the source, the release gate fails and no package is produced. The check lives in tools/build.mjs and you can run it yourself with "node tools/build.mjs --check".

The list of site theme conventions Nocturne recognises ships inside the add-on. There is no fix list to download and no update channel to phone home to.

WHAT IS STORED, AND WHERE

Your settings, in your browser's own extension storage, on your device:

• whether Nocturne is on, globally and per site
• your palette, brightness, contrast, colour and contrast-floor choices
• your schedule
• the hostnames you have set your own preferences for
• for each hostname visited, which method worked, so a repeat visit can skip the measuring step

That last item is a performance cache holding a hostname and a small number. It is capped at the 500 most recent entries. It is not browsing history, it is not sent anywhere, and clearing it costs nothing but a moment's extra work on the next visit.

One further value is held in session storage, which your browser clears when it closes: the stylesheet text currently applied to a tab, which is only needed so that it can be removed again cleanly.

Everything above is removed when you uninstall the add-on. You can clear it at any time from All settings with Reset everything, and export it as a file with Export settings.

WHAT NOCTURNE CAN SEE

Nocturne runs a content script on the pages you visit, because it has to change their colours and it has to do so before the page is first painted. In that content script it reads the colours the page has already rendered. It does not read, collect, transmit or store page text, form contents, passwords, cookies, URLs or anything else about what you are looking at.

It requests no host permissions at install.

The optional Stubborn sites feature asks for access to all sites when you turn it on, and only then. It is off by default. It is used for exactly one thing: injecting the generated theme as user-origin CSS, which is the only weight in the CSS cascade that outranks a page's own inline "!important" styles. You can withdraw the permission at any time by turning the option off.

THIRD PARTIES

There are none. No SDKs, no libraries loaded at runtime, no services.

CHANGES

Any change to this policy will appear in PRIVACY.md and CHANGELOG.md in the public repository before the version that changes it is published.

CONTACT

Open an issue at https://github.com/TiltedLunar123/nocturne/issues