Wellness · checked 2026-10-19Can I vibecode MacroFactor?
KINDA· weekend project
The brain of MacroFactor is a weight-trend filter and an expenditure estimate from what you eat and how your trend moves, which an agent can write in one sitting from first principles. The weekend goes to everything around it: a mobile-first logging screen with barcode scanning, and a food database. Open Food Facts and USDA data are free but patchy and partly crowd-sourced, while MacroFactor leans on a verified database of about 1.36 million items. If you can live with some wrong entries and logging from a phone browser, a personal version works.
$11.99/moprice
$144you'd save a year
weekendbuild time
—people replaced it
What you need on hand.
DifficultyIntermediate · Some system setup or keys.
TimeA weekend; the logging screen on a phone takes the longest
- Claude Code, Codex or CursorAny of them can run the prompt.
- Python 3.12 and uvNo native modules; SQLite ships with Python.
- A USDA FoodData Central API keyFree from the USDA site; put it in .env.
- HTTPS to reach it from your phoneCamera access and PWA install need it: a tunnel or a small VPS.
- Your MacroFactor exportMore > Data Management > Data Export gives spreadsheets of nutrition and weight.
Before you buildMacroFactor has no free plan, only a 7-day trial. OpenNutriTracker and Cronometer's free version cover basic logging at no cost.
- 1. Install one agent: Claude Code, Codex, Cursor.
- 2. Make an empty folder and open it in the agent.
- 3. Paste the prompt below, press enter, and answer its questions as it builds.
The prompt
Build me a calorie and macro tracker with a self-adjusting daily target to replace MacroFactor. Requirements: - Python 3.12: FastAPI with Jinja2 pages and a little HTMX, a web manifest and service worker so it installs as a phone PWA. `uv run fastapi run` serves http://localhost:4760. - Storage: SQLite (SQLAlchemy 2.0) in ./data/macros.db: foods (name, brand, barcode, per-100 g kcal, protein, carbs, fat, fibre, serving sizes, source), recipes, log entries that copy the macros at the time of logging, daily weights in kg, and a goal and profile. - Food lookup: search the local table first, then Open Food Facts (text and barcode) and USDA FoodData Central (`FDC_API_KEY` in .env). Cache every hit, show its source, and mark Open Food Facts entries as crowd-sourced. - Logging screen: recent foods first, quick-add calories and macros, copy yesterday's meal, recipes as ingredient sums with portions, and barcode scanning from the phone camera with the BarcodeDetector API and `@zxing/browser` as a fallback. - Weight trend: an exponentially smoothed line (alpha 0.1, configurable) that handles gaps. - Expenditure: over a rolling 21-day window, average logged kcal minus trend-weight change times 7,700 kcal per kg, divided by the days. Skip days I mark as not fully logged, and blend toward a Mifflin-St Jeor estimate while there is under two weeks of data. - Weekly check-in: from my goal (lose, hold or gain at a chosen kg per week) set next week's calorie target from the expenditure, split macros by protein g per kg and a fat share, and show the working step by step. - Charts with Chart.js: weight and trend, expenditure, calories against target, protein. - Single user. No accounts, no telemetry, local-first; the only outbound calls are food lookups. - Out of scope: workouts, native apps, photo or voice logging, vitamins and minerals, coaching. - README: setup, where food data comes from, and a warning that crowd-sourced entries can be wrong and that this is not medical advice.
Opens your agent with the prompt filled in, you press enter. Or copy it and paste it into an empty folder.
Then keep going
Next prompts, same folder.
The first prompt builds the core. Run these one at a time in the same folder to grow it into your own MacroFactor.
Extend the macro tracker in this folder. Requirements: - An import page for the spreadsheets from MacroFactor's Data Export: weight, nutrition and targets, as CSV or XLSX (`openpyxl`). - Map columns by header, show a preview, and skip rows that already exist by date and entry. - Recompute the trend and expenditure from the imported history. - Report rows that could not be read instead of dropping them. - Update the README.
Add label capture to the macro tracker in this folder. Requirements: - On the add-food screen, take or upload a photo of a nutrition label and extract per-serving values with an OpenAI-compatible vision endpoint from .env. - Show the extracted values in an editable form; nothing is saved until I confirm. - Say in the README exactly what is sent and that the model can misread numbers. - Update the README.
Add micronutrients to the macro tracker in this folder. Requirements: - Store a fixed list of micronutrients (iron, calcium, vitamin D, magnesium, potassium, sodium) per food when the source provides them. - A daily panel that sums them and compares each with a target I can edit. - Show which entries lack data, so a low total is not read as a deficiency. - Update the README, with a note that targets are mine to check with a professional.
Add weight import to the macro tracker in this folder. Requirements: - A /import/weights endpoint with a token from .env that accepts JSON posts of date and kg, for use with an iOS Shortcut. - Also accept a Garmin or Apple Health CSV upload with a column picker. - Never overwrite a weight I entered by hand for the same date; show conflicts. - Update the README.
What you lose
- The verified food database and its barcode coverage
- AI photo logging, label scanning and recipe import from a link
- Vitamin and mineral tracking, progress photos and body measurements
- Native iOS and Android apps with fast offline logging
- The refinements MacroFactor layers on its expenditure algorithm, such as its expenditure modifiers
Why people still pay
The pitch is that you only log food and weight and the app handles the maths, and the verified database makes logging fast enough to keep doing. That consistency is what people pay for; the formula alone is the easy part.
MacroFactor or your own copy?
Over
Your usage
12h ×$/h
MacroFactor, 1 yr$144
Your own copy, 1 yr$38running + build session
You keep$106pays for itself in the first month
Estimate · Runs on a $5 VPS or a home machine behind a tunnel; the food APIs are free. The build is token usage on your agent plan.
Take your data, then cancel.
1 · Take your data out of MacroFactor
- 1Tap More, then Data Management, then Data Export.
- 2Quick Export builds one spreadsheet for a chosen time frame with expenditure, weight trend, scale weight, calories, macros and your main targets.
- 3Granular Export lets you pick particular datasets and downloads a spreadsheet for each one.
- 4MacroFactor Workouts is a separate app with its own export article; progress photos and the food database itself are not part of the spreadsheets we read about.
2 · Cancel MacroFactor
- 1The subscription is held by Apple or Google, so MacroFactor can't cancel it: use your phone's app store.
- 2In the app, More > Subscriptions shows your active plan and renewal date and links to the store's own instructions.
- 3Deleting your account in the app does not cancel the subscription.
- 4A free trial is cancelled the same way, in the store, before it ends.
- Per the help center, Google Play refunds directly within 48 hours of purchase, and Apple refunds go through Apple's support portal.
- Legacy subscribers who got MacroFactor Workouts free keep that access only while they maintain the subscription, so cancelling can end it.
- Export before you cancel: spreadsheets of weight and nutrition are what a new tool can use to start warm.
- To remove your data entirely, the help center has a separate permanent-deletion article.
Checked 2026-10-19 against MacroFactor's docs: 1, 2, 3, 4, 5, 6
The escape hatch
Don't feel like building it? These are already free.
OpenNutriTrackerOpen sourceGPL-3.0 calorie, macro and micronutrient logger focused on privacy and simplicity, with Open Food Facts and USDA lookups.★ 2.7k · active Oct 2026 · one-click install
Android, iOSVisit ↗FitBookOpen sourceMIT Flutter app that works offline, with barcode scanning through Open Food Facts, macro tracking and graphs.★ 176 · active Oct 2026 · one-click install
Android, desktopVisit ↗CronometerFreeHosted nutrient tracker with a free version; the paid Gold tier adds more on top.they host it
Web, iOS, AndroidVisit ↗
Android, iOSVisit ↗FitBookOpen sourceMIT Flutter app that works offline, with barcode scanning through Open Food Facts, macro tracking and graphs.★ 176 · active Oct 2026 · one-click install
Android, desktopVisit ↗CronometerFreeHosted nutrient tracker with a free version; the paid Gold tier adds more on top.they host it
Web, iOS, AndroidVisit ↗
The numbers
MacroFactor pricing
| Plan | Monthly | Annual, per month | What you get |
|---|---|---|---|
| Monthly | $11.99 | — | Full app: food logging, barcode and label scanning, AI photo logging, weight trend, expenditure and weekly targets. |
| Every six months | custom | — | The same app. |
| Yearly | — | $5.99 | The same app. |
| Bundle with MacroFactor Workouts | — | $7.50 | Nutrition app plus the separate Workouts app. |
- Billing
- Auto-renewing subscriptions bought in the iOS or Android app; the site lists prices in USD and notes that local prices vary with exchange rates and tax. Cancelling is done in the phone's app store.
- Hidden costs
- MacroFactor Workouts is a separate app: the monthly, six-month and yearly prices above apply to it on their own, and the bundle is the way to get both.
- Source
- macrofactor.com
Also on the list
Related apps
No free tier. The apps offer a 7-day free trial.
Kinda. The core is a weekend build with the prompt on this page, but real gaps remain: The verified food database and its barcode coverage, AI photo logging, label scanning and recipe import from a link.
About $11.99 a month on the Monthly subscription plan, $143.88 a year (checked 2026-10-19).
The verified food database and its barcode coverage; AI photo logging, label scanning and recipe import from a link; Vitamin and mineral tracking, progress photos and body measurements; Native iOS and Android apps with fast offline logging; The refinements MacroFactor layers on its expenditure algorithm, such as its expenditure modifiers. If any of those matter to you, keep paying.
Yes: OpenNutriTracker (open source), FitBook (open source), Cronometer (free).