Running Next.js in ChatGPT: How to Build ChatGPT Apps

What this post added

This post details the technical challenges and solutions for running a Next.js application within ChatGPT's nested iframe architecture. It addresses issues with asset loading by using `assetPrefix`, relative URL resolution by implementing a `<base>` HTML element, browser history leaks by patching `history.pushState` and `history.replaceState`, fetch request rewriting for client-side navigation by patching `window.fetch`, and CORS issues by implementing middleware to handle OPTIONS preflight requests and add CORS headers. It also covers patching parent frame modifications and ensuring external links navigate correctly.