One File · Powerful health tracker
Every glass.
Every cup.
A hydration and caffeine log in one HTML file. Water, coffee, tea, espresso, matcha — and a caffeine half-life estimator that tells you how many mg are still circulating right now, deciding the 4pm cup for you.
One payment · Yours forever · 14-day refund
- Works fully offline
- Installs as an app (PWA)
- No account, ever
- Yours, forever
Loads once, never needs the internet again. On a plane, in a basement, in a foreign hotel.
Every entry, every chart — stored locally. We never see it. We can't.
No subscription. No upgrades. No re-up next year. One file, yours.
Why track
Why coffee-loving sleepers end up logging.
Sleep is downstream of caffeine; caffeine is upstream of memory.
Half-life beats hard cutoffs.
Telling yourself 'no coffee after 2pm' is rules. The half-life estimator tells you 'you have 110mg still in you at 4pm — half-cup territory only'. Decision made.
Water target is achievable when measured.
2L feels arbitrary. The progress bar makes it visible — and the gap between today and target is real.
By-type donut reveals real diet.
You think you drink mostly water. The donut says 30% coffee, 25% tea. Plan accordingly.
Heatmap honest about hydration discipline.
16 weeks of drinks heatmap. The bad weeks show up; the good weeks show up. Patterns emerge.
realistic 5-11 drinks/day
from water to wine to matcha
no recurring fee, ever
log a sip on a flight, no signal
Inside the file
Eight things you'll use every day. Plus a dozen more.
One file. One dashboard. Every feature you'd expect from a "real" app — without the cloud, the cookies, or the £8/month.
Quick add
Log a drink from the home screen — three taps and back to your day.
Live insight banner
The single number that matters today, computed in real time from your entries.
Streak calendar
Daily streak across the last weeks. Showing up becomes the default.
By type (30d)
Visual split across categories so the pattern becomes obvious without squinting.
Searchable, sortable list
Every entry findable in seconds — search across notes, sort by anything.
Free-form notes
A textarea per entry for the things that don't fit a field.
PNG share cards
One-tap share card of your stats, ready for Instagram or a group chat.
Cross-entity links
Reference one entity from another — relationships stay intact across edits.
Offline, always
Loads once, runs forever without a network connection.
Installs as a PWA
Add to home screen — opens like any native app.
CSV in / CSV out
Bring your old data in. Take everything with you. No lock-in.
No account, ever
No email, no signup, no analytics, no third-party tracking.
Yours forever
If we vanish tomorrow, your tracker keeps working — local file, no server.
Light + dark
Auto-follows the system. Or pick one and stick with it.
Today
Today, at a glance.
The home screen pulls together what just happened and what's coming up — clean enough to actually look at every morning.
- Live insight banner — your unique angle, computed from your entries
- Four-tile stat grid surfacing the numbers that matter today
- Streak calendar showing the last weeks at a glance
- Quick-add button — log without leaving the home screen
- Recent entries on the dashboard so the last log is one tap away
Drinks
Every drink, in one place.
Date, time, type, amount (ml) per row. Sortable, searchable, groupable.
- Search across notes
- Sorted by date (newest first)
- Group by type with one tap
- 6 fields per entry — the right amount of detail
How it's different
What you give up vs. wellness apps. AI hydration nudges and an account.
Compared with subscription hydration apps.
- Pricing modelPay once · $6.99£8 – £15 / month, forever
- Account requiredNoYes
- Caffeine half-life estimatorYesRare
- Water target progressYesYes
- AI 'coach' notificationsNoYes
- Data stays on your deviceYesNo
- Ads or upsellsNoYes
The promise
Your kettle is your business.
Not a wellness platform's.
Offline, always
Open it once, never need the internet again. The file holds the whole app.
Local-first storage
Every entry stored in your browser, on your device. No server sync. No leaks. Nothing to breach.
One payment, forever
No subscription, no upgrade tier, no nag. If we shut down OneFileClub tomorrow, your file keeps working.
Data does not sync automatically between phone and desktop
This is a local-first app — everything stays on the device you logged it on. To use it on both phone and desktop, use the built-in JSON or CSV export on one device and import on the other when you want to keep them in step.
Every view, light and dark.
A look at every screen across both themes — your tracker, populated.
Questions
Real answers, no fine print.
Is the half-life estimate accurate?+
It uses a 5-hour half-life model — the median for adults. Individual metabolism varies. Treat it as a directional signal, not a clinical readout.
Does it count tea / matcha caffeine accurately?+
Yes — caffeine mg is a per-drink field, so you can tune it to your specific brand. Defaults are reasonable averages.
Where is my data stored?+
Locally, in your browser, on your device. Nothing is sent to OneFileClub or anyone else — there is no account, no cloud sync, no analytics.
Does it work offline?+
Yes. Once your personalised copy loads the first time, the entire tracker runs from a single HTML file. Airplane mode is fine.
What does 'personalised copy' mean?+
When you buy, OneFileClub stamps a private copy with your licence and deploys it to a unique URL just for you. You bookmark it, install it as an app, or save the file — and the file is yours, even if OneFileClub disappears tomorrow.
What is your refund policy?+
14 days, no questions asked. Email us, we'll process it and disable your private URL.
One payment.
Better-decided coffee.
We'll personalise a copy and email you a private link. Bookmark it, install it, log the next sip.
14-day refund · No subscription
