wtf is nextdoctor?

nextdoctor is a command line tool that watches, diagnoses, and fixes memory problems in Next.js development servers. Next.js dev servers can hold onto a growing amount of memory as a developer visits more routes and pages while working, and how bad this gets depends on the Next.js version, the bundler in use, and the project's configuration. This tool gives visibility into what is actually happening and offers one command tuning to help. A person can try it on a single project without installing anything, by running it directly through npx inside their Next.js project folder. Once someone decides they like it, it can be installed globally so the command is available across every project, or installed as a per project development dependency. The tool has three main commands. Diagnose runs a static scan of the current project, checking the Next.js version, whether Turbopack's memory eviction feature is being used, and whether the project is part of a monorepo setup. Fix applies the safe changes that diagnose suggests, such as tuning entry settings or removing a setting that accidentally disabled memory eviction, and it always makes a backup of the configuration file first and shows what it plans to change before writing anything. Dev wraps a project's actual development command and shows a live dashboard of memory usage across the whole process tree, including any worker processes Next.js spawns, with the option to automatically restart the server if memory crosses a set limit. It can also watch several apps at once, which is useful for monorepos with multiple dev servers running side by side. The project runs entirely on the developer's own machine, with no telemetry and no network calls, and only touches the project files it is pointed at. The author describes it as an early version, where the fix command intentionally makes small, easy to review text changes to configuration files rather than a full automated rewrite.