@honghong **code-serve**r is the IDE (basically, Visual Studio Code running in the server environment, and usable through the web browser UI... yeah... the visual part runs in the browser, but the file system is at the server, the terminal/SSH console is the server CLI...), while Coder is a web app managing workspaces (development environments) based on templates (development environment configurations)... these templates describe the dev environment system (OS, software, dependencies, etc), and they may contain code-server as one of its items... so, from Coder web UI, one can click a button and spin a full "dev server", with all required stuff for a project's development, and also a ready-to-use IDE in the browser.