① Product Title
Suggested subtitle:
"A professional, privacy-first blood glucose tracker that runs entirely in your browser — no cloud, no subscription, no account. One purchase, yours forever."
② Early Bird Banner — paste at the very top of description
💡 After 30 days: raise Gumroad price to £45, remove this banner, update the CTA blocks below to remove "Early Bird" references.
③ Opening Hook
Blood Glucose Trend Manager is a professional, privacy-first health tracking tool that gives you real insight into your blood glucose patterns — with no cloud, no account, no subscription, and no one else's hands on your data.
Log readings, visualise trends, spot problem patterns before your next appointment, and walk into your doctor's office with a professional two-page PDF report already in hand.
One-time purchase.
Instant download.
All future updates included.
④ The Pitch
Most health tracking apps ask for your email address, your date of birth, and your most sensitive medical data — then store it on servers you have no control over, behind a paywall that renews every year.
Blood Glucose Trend Manager was built on a different principle: your data belongs to you, and only you.
Every reading you log is stored directly in your browser's local storage — the same private space a site uses to remember your preferences. Nothing is transmitted anywhere. There is no server. No company database. No breach risk. No terms-of-service update that suddenly makes your health history someone else's asset.
And yet it's genuinely powerful: interactive trend charts, automatic pattern alerts, timing analysis by meal period, customisable target ranges, smart insights in plain English, and a clean professional PDF report ready for your next appointment.
Apps like MySugr Pro cost around £27 per year — and that buys you a subscription to someone else's server. Blood Glucose Trend Manager costs £35 once, runs entirely on your own device, and includes every future update. In year two you're already ahead. In year three you've paid for it twice over — and your data has never left your hands.
⑤ Features
Colour-coded line charts over 7, 14, 30, or 90 days. High readings in red, lows in amber, normal in green. See your patterns at a glance.
Set your own High and Low thresholds to match your doctor's recommendations. They flow through every chart, alert, statistic, and PDF report automatically.
Rising trend, falling trend, persistent highs — detected and surfaced as a clear colour-coded alert before you have to go looking.
Average glucose by measurement period: fasting, pre-meal, 1hr post-meal, 2hr post-meal, bedtime. Understand precisely when spikes happen.
Plain-English analysis flags high fasting averages, large variability, and recent concerning patterns — observations your eye might miss.
A clean two-page PDF in one click: summary statistics, high/normal/low breakdown, trend chart, and record table — formatted to hand directly to your GP or specialist.
Switch units with a single click. Charts, statistics, history, and reports all update instantly. Your preference is remembered between sessions.
Download your full history as a CSV at any time. Import it back to restore from a backup or migrate to a new device — with automatic duplicate detection. Your data is never locked in.
Entered the wrong time or value? Edit any saved record directly — without having to delete and re-enter. Changes take effect immediately.
At-a-glance progress bars show your overall split of High, Normal, and Low readings — with percentages that update as you log more data.
If your browser's local storage approaches its limit, a warning prompts you to export a backup before any data is at risk.
Fully responsive. Chrome, Firefox, Safari, Edge. Desktop, tablet, mobile. Windows, macOS, iOS, Android. Any modern browser, any device.
⑥ Privacy
Health data is the most sensitive personal information you have. Blood glucose readings, dates, times, meal patterns — in the wrong hands, this is exactly the kind of data that feeds insurance risk models, targeted advertising, and data broker profiles.
Blood Glucose Trend Manager collects none of it. The app has no server. No account system. No analytics. No cookies. No back-end of any kind.
Every reading you enter lives exclusively in your browser's local storage on your own device. Billion Studio cannot see it, access it, or retrieve it — because it is never sent anywhere. The only people who can see your health data are you and anyone you physically hand your device to.
You are in complete control. Export your data whenever you like. Delete it whenever you like. Stop using the tool — and nothing lingers anywhere.
⑦ Who This Is For
⑧ How It Compares
Most alternatives ask you to choose between powerful but cloud-dependent and private but primitive. This tool makes that trade-off unnecessary.
| Feature | This tool | Spreadsheet | Cloud app |
|---|---|---|---|
| Pricing model | ✓ One-time £35 | ✓ Free | ✗ ~£27+/year |
| Data stays on your device | ✓ Guaranteed | ✓ Yes | ✗ Uploaded to server |
| No account required | ✓ None needed | ✓ None | ✗ Required |
| Automatic trend analysis | ✓ Built in | ✗ Manual | ✓ Yes |
| Professional PDF report | ✓ One click | ~ DIY effort | ~ Some only |
| Customisable target ranges | ✓ Yes | ~ Manual formula | ~ Premium tier |
| mg/dL + mmol/L toggle | ✓ Both | ~ Manual | ~ Varies |
| CSV export & import | ✓ Both directions | ✓ Native | ~ Export only, usually |
| Works offline | ✓ Fully | ✓ Yes | ✗ No |
| Mobile-friendly | ✓ Responsive | ✗ Poor on mobile | ✓ Yes |
| Future updates included | ✓ All included | N/A | ✗ Subscription required |
⑨ What's Included
1. Download and unzip → 2. Double-click index.html → 3. Enter your profile once → 4. Start logging. No installation. No account. No configuration.
⑩ Technical Details
| Format | Single HTML file — no installation, no dependencies |
| Internet required | First load only (libraries cached). Fully offline after that. |
| Browsers | Chrome, Firefox, Safari, Edge — all current versions |
| Devices | Desktop, laptop, tablet, mobile (fully responsive) |
| Operating systems | Windows, macOS, Linux, iOS, Android |
| Data storage | Browser localStorage — local device only, never transmitted |
| Storage capacity | ~5 MB (several thousand readings). Built-in warning before limit. |
| Units supported | mg/dL and mmol/L — switchable at any time |
| Export formats | PDF report, CSV export + import |
| Languages | English (app) · English + Traditional Chinese (legal docs) |
| Version | v1.1.0 (March 2026) |
| Updates | All future versions included with purchase |
⑪ FAQ
No. Blood Glucose Trend Manager is a single HTML file. Download the zip, unzip it, and double-click index.html to open it in your browser. There is no installation, no setup, and no configuration of any kind.
Yes. The app is fully responsive and tested on mobile browsers. On iPhone, open the file in Safari. On Android, open it in Chrome. You can add it to your home screen for quick access — it behaves like a native app without being one.
Only for the very first load, which fetches a few small chart and PDF libraries and caches them. After that, the app works entirely offline — logging, charts, analysis, and PDF generation all work with no internet connection.
Completely. Every reading is stored in your browser's local storage — it never leaves your device. Billion Studio has no server, no database, and no means of accessing your data. The app contains no analytics, no tracking, and no data collection of any kind.
The only people who can see your health data are you and anyone you physically share your device with.
Clearing browser cache alone typically does not affect local storage. However, clearing site data or local storage will delete your saved records from that browser. This is why we recommend using 📥 Export CSV regularly — it downloads a backup of all your records that you can import back at any time.
Yes. Export your records as a CSV from your current browser, then open the app on the new device or browser and use 📤 Import CSV to restore them. The import automatically detects the unit (mg/dL or mmol/L) and skips any duplicates already in your history.
Yes — mmol/L is fully supported. Click the unit toggle in the top bar to switch at any time. All charts, statistics, the history table, and PDF reports update instantly. Your preference is saved automatically between sessions.
Yes. Click ⚙️ Settings in the top bar to set your own High and Low thresholds. Your custom ranges are applied everywhere: history table, anomaly statistics, trend chart reference lines, smart alerts, and PDF reports. When non-default ranges are used, the PDF adds a "User-defined ranges" note so your doctor is informed.
Yes. Click the ✏️ button beside any record in the history table to open the edit panel. You can update the date, time, value, timing type, and notes. Changes take effect immediately across all views, charts, and statistics.
Click 📄 Generate PDF Report in the History section. The app creates a professionally formatted two-page PDF: summary statistics, high/normal/low breakdown, trend chart, and a record table — ready to print or email to your GP or specialist.
If you have more than 50 records, the PDF table shows the most recent 50. Your full dataset is always available via CSV export.
No. Blood Glucose Trend Manager is a personal tracking and visualisation tool. It is not a medical device, is not regulated by any health authority (MHRA, FDA, or equivalent), and does not provide medical advice, diagnosis, or treatment.
It is designed to complement your existing healthcare relationship — not replace it. Always consult your doctor or a qualified healthcare provider for any medical decisions.
Yes — all future updates are included with your purchase and delivered automatically via Gumroad. If a bug is discovered, an updated version will be issued and you'll be notified.
Because all data is stored locally in your browser, updating the HTML file has no effect on your records whatsoever.
Yes — with one note: the app stores data per browser profile. For separate records, use separate browser profiles (most modern browsers support this) or separate devices. The purchase licence covers personal and household use.
Because this is a complete, maintained product — not a side-project template. The price reflects professional-grade features, full legal documentation (Terms of Use and a UK GDPR-compliant Privacy Policy), a comprehensive user manual, genuine privacy architecture, and ongoing updates at no extra cost.
Comparable subscription apps cost £27 or more per year. At £35 once, this tool pays for itself in under 18 months — and your data never touches anyone else's infrastructure.
Because this is a digital product that can be downloaded and used immediately, all sales are final. However, if you encounter a genuine technical issue that prevents the product from working as described, please contact hello@billionstudio.co.uk and we will do our best to resolve it.
Email us at hello@billionstudio.co.uk. We typically respond within 2 business days.
⑫ Closing CTA
No subscription. No renewal reminder. No account to manage. No data to worry about. Just a capable, private tool that helps you understand your own health — on your terms, for as long as you need it.
Blood Glucose Trend Manager is available at the Early Bird price of £35 for the first 30 days. After that, the regular price of £45 applies. Your purchase includes the complete package and all future updates.
Instant download.
All future updates included.
No subscription, ever.