replr is a Node.js library that enables remote access to a REPL (Read-Eval-Print Loop) for Node applications and services, supporting cluster and worker selection. It allows developers to remotely connect to their Node app using HTTP upgrade, netcat, or telnet, and provides features like listing exported methods and variables, switching REPL context between workers, and accessing the REPL over a Unix domain socket. This tool is ideal for Node.js developers who need to debug or interact with their applications in real-time, especially in clustered environments.