Why Circadianly Works Offline and Never Asks for Your Data
When you look for an energy or circadian rhythm app, you’ll find a consistent pattern: account required, subscription recommended, data collected. The apps argue this is necessary — to store your preferences, sync across devices, improve the product.
It’s not always necessary. Circadianly is a circadian energy zone tracker that requires no account, stores nothing on any server, works entirely offline, and is completely free. This isn’t a temporary feature — it’s a design decision rooted in a specific philosophy about what a productivity tool should and shouldn’t do.
Here’s why we built it this way, and what it actually means for you in practice.
The data privacy problem with energy trackers
The most popular circadian and energy tracking apps share a common architecture: they collect behavioral, physiological, or usage data and store it on their servers.
Rise Science (a major player in the circadian app space) requires account creation and collects sleep data, usage patterns, and behavioral information. Their business model involves subscription fees and, depending on their terms, potential use of aggregated user data to improve or sell their product. The app itself is genuinely useful — but you’re paying with both money and personal data.
Many wearable-connected apps (Oura, Whoop, RISE) go further, collecting continuous physiological data: heart rate variability, body temperature, movement, sleep staging. This data is highly personal, stored on external servers, and subject to policy changes over time.
There’s nothing inherently wrong with this architecture if users understand the trade-off. But there’s a subset of users — particularly those in sensitive professional environments, those with strong privacy preferences, and those who simply don’t want another account — for whom this model is a barrier, not a feature.
Why Circadianly stores nothing on servers
The honest answer is that it doesn’t need to.
The core function of Circadianly is calculating your current circadian energy zone based on your wake time. That calculation uses a fixed algorithm and a single input: when you woke up. No continuous data collection required. No historical data required. No profile required.
The zone calculation is deterministic — the same wake time always produces the same zone schedule. There is nothing to learn about you over time that would improve this calculation. You don’t get a “better” energy zone estimate by sharing more data. You get the same estimate every time, because the circadian model is the same for everyone (with minor chronotype adjustments).
This means the entire function of the app can run locally, in your browser, with your data never leaving your device. Wake time is stored in your browser’s local storage — the same place a website might store your display preferences. It’s on your device, under your control.
How offline-first architecture works
“Offline-first” is an architectural choice that means the application is designed to work without any network connection, and network access is never required for core functionality.
In Circadianly’s case:
- The zone calculation algorithm runs entirely in the browser’s JavaScript environment.
- Your wake time is read from
chrome.storage.local— device-local storage that Chrome browser extensions can access. - The extension reads the current time from your device clock (
new Date()in JavaScript). - The result is displayed in the extension popup.
None of these steps involve a network request. If you turn off your internet connection completely, Circadianly continues to work without any change in behavior. There’s simply nothing to connect to.
For Google Calendar integration (an optional feature that shows your calendar events alongside zone information), an OAuth token is required — but this is a direct, user-controlled connection between your browser and your Google account. Circadianly doesn’t receive or store your calendar data on its servers. It reads your events locally within the browser session.
What this means for you practically
No account, no password, no subscription. You install the extension, enter your wake time, and you’re done. There’s no sign-up flow, no email confirmation, no credit card, no trial period. It takes about 30 seconds from installation to first use.
Instant start. There’s no onboarding that requires historical data. Other circadian apps often ask for several days or weeks of tracked data before they can give you useful information. Circadianly starts working with the first wake time you enter.
No data to lose. You can’t have your energy tracking data breached because there’s no database storing it. There’s nothing to be subpoenaed, sold in an acquisition, or exposed in a security incident.
Works in any connectivity environment. Useful for people who work in restricted network environments, travel frequently, or simply don’t want another app that requires internet access to function.
GDPR and privacy compliance by architecture. Data minimization is a core principle of GDPR — collect only what you need, for as long as you need it. Circadianly satisfies this not through a privacy policy document, but through its technical design. No personal data is collected. The privacy policy isn’t a list of safeguards around data collection; it’s a statement that there is no data collection to safeguard.
Comparison: Circadianly vs apps that require your data
| Circadianly | Rise Science | Wearable apps | |
|---|---|---|---|
| Account required | No | Yes | Yes |
| Subscription fee | Free | $69.99/year | $150–350/year (device) + app |
| Data stored on servers | None | Sleep + usage data | Continuous biometric data |
| Offline functionality | Full | Limited | Limited |
| Setup time | ~30 seconds | Several days (data needed) | Days to weeks |
| Works in browser | Yes (extension) | No | No |
The comparison isn’t meant to argue that data-driven apps are bad. For users who want personalized insights backed by continuous monitoring, wearable-connected apps offer something Circadianly doesn’t: data-driven personalization over time.
But for users who want circadian zone awareness without the overhead of an account, a subscription, or data sharing, there wasn’t a good option. Circadianly is that option.
The underlying belief
Productivity tools should remove friction, not add it. An energy tracker that requires you to create an account, maintain a subscription, and share your behavioral data is asking for a significant commitment before it delivers any value. That commitment is a barrier that prevents many people from getting the benefit.
Circadianly’s design hypothesis is that the core value of circadian zone awareness — knowing whether you’re in your cognitive peak, your afternoon dip, or your creative rebound — can be delivered with zero data collection, zero accounts, and zero network requests.
So far, that hypothesis has held. The zones are accurate. The tool is useful. And you don’t have to trust anyone with anything to use it.
Install Circadianly from the Chrome Web Store — or check what zone you’re in right now with the energy zone calculator without installing anything.
See also: The 5 Circadian Energy Zones: What They Are and How to Use Them at Work · Privacy Policy