This document discusses different approaches to building web applications with multiple teams using different JavaScript frameworks, known as micro front-ends. It describes recipes like using multiple single-page applications at different URLs, web components, iframes, a shared event bus, and the single-spa framework. The single-spa framework allows hosting multiple applications inside a single SPA and implements cross-application routing. Other approaches discussed include using custom elements as an integration layer and a layout service to compose a website out of fragments from different teams. In summary, there are many recipes for building micro front-ends but no significant leader, though single-spa is a popular option.