diff --git a/demo/rustfmt.toml b/demo/rustfmt.toml
new file mode 100644
index 0000000..3a26366
--- /dev/null
+++ b/demo/rustfmt.toml
@@ -0,0 +1 @@
+edition = "2021"
diff --git a/demo/src/main.rs b/demo/src/main.rs
index e7a11a9..85ddfe9 100644
--- a/demo/src/main.rs
+++ b/demo/src/main.rs
@@ -1,3 +1,37 @@
-fn main() {
-    println!("Hello, world!");
+use axum::{routing::get, Router};
+use clap::Parser;
+use std::net::{IpAddr, Ipv4Addr, SocketAddr};
+use std::path::PathBuf;
+use tokio::net::TcpListener;
+
+#[derive(Parser)]
+struct Args {
+    #[arg(short, long)]
+    zip: Option<PathBuf>,
+
+    #[arg(short, long, default_value = "8001")]
+    port: u16,
+}
+
+#[tokio::main]
+async fn main() {
+    tracing_subscriber::fmt::init();
+    let args = Args::parse();
+
+    // TODO: Add a test to see if `path`, if it exists, is a path to a folder or to a zip file. If a
+    // folder, opt for using serve_dir instead.
+    match &args.zip {
+        Some(path) => println!("Using external zip file: {}", path.display()),
+        None => {
+            println!("Using embedded zip file, if present.  (TODO: Make this an error otherwise)")
+        }
+    }
+
+    let app = Router::new().route("/check", get(|| async { "OK" }));
+    let addr = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), args.port);
+    let listener = TcpListener::bind(addr)
+        .await
+        .expect("Failed to bind to port");
+    println!("Listening at {}", addr);
+    axum::serve(listener, app).await.unwrap();
 }
diff --git a/rustfmt.toml b/rustfmt.toml
new file mode 100644
index 0000000..3a26366
--- /dev/null
+++ b/rustfmt.toml
@@ -0,0 +1 @@
+edition = "2021"
diff --git a/serve_zip/rustfmt.toml b/serve_zip/rustfmt.toml
new file mode 100644
index 0000000..3a26366
--- /dev/null
+++ b/serve_zip/rustfmt.toml
@@ -0,0 +1 @@
+edition = "2021"