Making Open Transit Data Visible: How a Next.js Migration Changed What Google and LLMs See

MobilityData maintains the MobilityDatabase, an open repository of transit data used by developers and agencies worldwide. Our pages were public. Our data was open. And none of it was properly visible to search engines. This is the story of how we migrated from a React SPA to Next.js, what we gained beyond performance numbers, and what surprised us along the way. The Problem: Invisible Public Data MobilityData is a global non-profit dedicated to making transportation systems interoperable through open data standards. We maintain the MobilityDatabase, an open catalog of over 6,000 GTFS, GTFS Realtime, and GBFS feeds across 99+ countries, used by developers, transit agencies, and researchers to build tools and services that help people get around without driving alone. Our application was a standard React single-page application. It worked well for users who landed on it directly, but it had a fundamental problem: when Google crawled our pages, it would do its best to parse the JavaScrip