litro.ch — Smart fuel-price comparison & route refueling strategy for European drivers Stop guessing where to refuel on your next road trip. litro.ch shows you live average fuel prices across 17 European countries and tells you exactly how many liters to buy in each — to minimize total trip cost. What it does litro.ch is a Progressive Web App that solves two problems for drivers in Switzerland and the surrounding region: 1. Price comparison — aggregates current diesel & gasoline prices from 17 countries (CH, DE, AT, FR, IT, SI, HU, ES, PT, HR, NL, DK, BE, PL, CZ, SK, SE) and shows them all in CHF/L for direct comparison, with up/down trend indicators since the last update. 2. Trip optimization — enter a start and destination, and litro.ch calculates the optimal refueling strategy. For each country on your route, it tells you whether to fill up, top up to a specific %, or just drive through — based on a greedy solution to the classical "gas station problem" with your tank size and consumption as constraints. Includes estimated savings vs. the naive "fill once at home" strategy. Key features - 🌍 17 countries — live data from official sources (Tankerkönig, EU Weekly Oil Bulletin, TCS, Avenergy) - 🗺️ Route planner with autocomplete (Photon/OSM), turn-by-country distance breakdown - ⛽ Optimal refueling strategy with concrete liter recommendations per country - 📊 PDF & CSV export of your route plan - 📱 PWA — installable on iOS/Android/desktop, works offline - 🔒 Privacy-first — no accounts, no cookies, no trackers - 🌗 Light & dark mode - 🇨🇭 German UI, currency conversion to CHF (other languages on the roadmap) Built with A vibe-coded side project — single-file PHP backend (~1700 LOC) and a single HTML file with vanilla JS frontend (~2000 LOC, no framework, no build step). All data sourced from free public APIs: - Routing: OpenRouteService (free tier) - Geocoding: Nominatim + Photon (OSM) - Country borders: Nominatim simplified polygons (cached locally for in-country point detection) - Hosting: plain shared PHP hosting The whole codebase is under 4000 lines and was built and iterated with Zed assisted from Claude Code, including the greedy gas-station algorithm and a SaaS-pivot roadmap. Try it 👉 https://litro.ch (the summer holidays are just around the corner)