node-inspector

Node Inspector was a debugging tool for Node.js applications that let developers inspect and step through their server-side JavaScript code using a browser-based interface. It worked by connecting Chrome's developer tools to a running Node.js process, giving you the same visual debugging experience you would get when inspecting code in a web browser.

The feature list covered most of what developers need during debugging: setting breakpoints with optional trigger conditions, stepping through code line by line, inspecting variables and object properties, viewing console output, and profiling CPU and memory usage. You could also edit code while it was running, with an option to save those changes back to disk. Remote debugging was supported, meaning the browser did not need to be on the same machine as the Node.js process.

Setup was a single npm install command, and a second command called node-debug would launch your application and open the debugger in the default browser. Only Chrome and Opera were supported; other browsers would not work with the interface.

An important note in the README: as of Node.js version 6.3, Node.js itself includes a built-in debugger based on the same DevTools technology. The project authors state that this built-in option mostly replaces Node Inspector and is developed directly by the team behind the V8 JavaScript engine. They recommend the built-in debugger for anyone getting started today, noting it supports advanced features such as long and async stack traces that are difficult to implement externally.

The repository is still publicly available and the README documents the original features, known issues (such as problems with large Buffer objects and debugging multiple processes running in parallel), and troubleshooting steps for common setup problems.