The problem
Available calorie-tracking apps were slow, heavy and required a permanent internet connection. Product databases were often incomplete and macronutrient tracking was clunky.
Fitston — a calorie tracker that stays out of your way
A PWA for tracking calories and macronutrients, built from scratch — because no available app worked the way it should. The case study is being expanded alongside the product.
PWANext.jsTypeScriptMongoDB
The solution
A minimal PWA running in the browser: fast, with an extensive product database and a full nutritional profile — from energy, through fats and carbohydrates, to 12 minerals and 14 vitamins.
Architecture
Next.js on the frontend, Fastify on the backend, MongoDB as the database. Client and server exchange data through a REST API with JWT authentication.
Client — Next.js PWA
React + TypeScript + Sass. A browser-based interface, installable on a device.
Server — Fastify
REST API with helmet, rate-limit and MongoDB data sanitization (protection against NoSQL injection).
Key features
What sets Fitston apart from a typical calorie counter.
Barcode scanner
Add products from the shelf in seconds — no manual typing.
Full nutritional profile
265 products in the database, each with a full profile: energy, fats (including omega-3/6/9), fiber, proteins, 12 minerals and 14 vitamins.
Macronutrient goals
Customizable kcal, protein, fat and carbohydrate goals — broken down into grams and percentages.
See it in action
Screenshots from production — no stock images, real screens of the system in use.
Technology stack
TypeScriptNext.jsReactPWASassFastifyMongoDBChart.js