# The serve command

The serve command is used to preview a book by serving it via HTTP at localhost:3000 by default:

mdbook serve


The serve command watches the book's src directory for changes, rebuilding the book and refreshing clients for each change; this includes re-creating deleted files still mentioned in SUMMARY.md! A websocket connection is used to trigger the client-side refresh.

Note: The serve command is for testing a book's HTML output, and is not intended to be a complete HTTP server for a website.

#### Specify a directory

The serve command can take a directory as an argument to use as the book's root instead of the current working directory.

mdbook serve path/to/book


### Server options

The serve hostname defaults to localhost, and the port defaults to 3000. Either option can be specified on the command line:

mdbook serve path/to/book -p 8000 -n 127.0.0.1


#### --open

When you use the --open (-o) flag, mdbook will open the book in your default web browser after starting the server.

#### --dest-dir

The --dest-dir (-d) option allows you to change the output directory for the book. Relative paths are interpreted relative to the book's root directory. If not specified it will default to the value of the build.build-dir key in book.toml, or to ./book.

#### Specify exclude patterns

The serve command will not automatically trigger a build for files listed in the .gitignore file in the book root directory. The .gitignore file may contain file patterns described in the gitignore documentation. This can be useful for ignoring temporary files created by some editors.

Note: Only the .gitignore from the book root directory is used. Global \$HOME/.gitignore or .gitignore files in parent directories are not used.