# Circadian

> A browser extension that tints pages by time of day (daytime, sunset, bedtime).

Canonical page: [https://chrome-stats.com/d/circadian](https://chrome-stats.com/d/circadian)

## Overview

- **ID:** `circadian`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Pasithea
- **Category:** appearance
- **Daily users:** 1
- **Version:** 1.0.4
- **Last updated:** 2025-11-10
- **First published:** 2025-10-31
- **Size:** 77 KB
- **Data as of:** 2026-09-12
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/circadian/)
- **Website:** [https://github.com/Pasithea0/circadian-extension](https://github.com/Pasithea0/circadian-extension)

## Description

Circadian is really simple. It creates an invisible element over your whole web page, then applies a CSS filter to it! There's a bit of math involved to calculate the RGB values from the blackbody radiation scale, but that's essentially it!

Philosophy:
Blue-light impacts our sleep and overall health by disrupting melanopsin receptor's normal function that calibrates our circadian rhythm. This extension's creation was inspired by f.lux's ability to adjust your device's color profile temperature based on the time of day to aid in preventing this. It's not perfect (this extension definitely isn't) but it's a simple tool many users use to help.

The idea: I was checking out some dark reader Firefox addons when I asked myself if any of these dark reader addons had temperature adjustments? I suspect not. And if I were to make an extension, I could use Orion on my iPhone to install my extension and essentially get f.lux on my iPhone! (Apple shut down f.lux's app) Obviously it's not system wide, but still kinda neat!

You can even pair Circadian with other dark reader extensions to get the best experience!

## Rankings

- #118,518 — Overall
- #117 — temperature

## Permissions and access

### Permissions

- `storage`
- `activeTab`

### Host permissions

- `https://*/*`

### Content script matches

- `<all_urls>`

## Safety

- **Risk impact:** Moderate risk impact
- **Risk likelihood:** Moderate risk likelihood

### Analysis details

- Allows access to all websites, posing a significant security risk as it can monitor and modify data from any visited site.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/circadian)