Kreni (also known as ZET Live) is a frontend-only web application designed to track Zagreb’s public transport—trams and buses—in real-time. It provides lightning-fast performance, real-time stop locations, schedule data, and route visualization without a backend server!

Features

• Real-Time Data: Tracks stop locations and route information interactively.
• Continuous Vehicle Tracking: Seamlessly follow any active vehicle along its route directly on the map.
• Parking Zones Integration: View up-to-date city parking zones integrated directly into the map view.
• Sibling Platform Routing: Easily navigate and switch between opposite direction platforms at the same stop.
• Optimized Data Pipeline: Pre-processes 114 MB of GTFS data into highly optimized JSON chunks.
• Smart Chunking & Fetching: Provides an extremely fast load time (approx. 450 KB initial load, 3KB-70KB per interaction).
• PWA Support: Native-like experience with installability prompts and caching.

Visuals

Here is how the application looks on different screen formats.

Technical Stack

• Vite 7: For incredibly fast builds.
• React 19: Utilizing the latest features of React with strict TypeScript.
• Tailwind CSS v4 & DaisyUI 5: Highly customized and themed user interface.
• Data Pipeline: Custom Python scripts optimizing the initial transit data and saving it statically to a CDN.

Architecture

This application represents a paradigm shift where complex spatio-temporal datasets can be intelligently chunked and served purely from static files. It caches the schedule information in memory directly in the browser and loads extra details seamlessly on-the-fly, reducing server costs and infrastructure needs significantly.