diff --git a/configuration.development.js b/configuration.development.js
deleted file mode 100644
index d561802..0000000
--- a/configuration.development.js
+++ /dev/null
@@ -1,15 +0,0 @@
-module.exports = (require) => {
-  const path = require("path");
-  const killTheNewsletter = require(".").default;
-  const { webApplication, emailApplication } = killTheNewsletter(
-    path.join(__dirname, "data")
-  );
-
-  webApplication.listen(new URL(webApplication.get("url")).port, () => {
-    console.log(`Web server started at ${webApplication.get("url")}`);
-  });
-
-  emailApplication.listen(new URL(webApplication.get("email")).port, () => {
-    console.log(`Email server started at ${webApplication.get("email")}`);
-  });
-};
diff --git a/package.json b/package.json
index 924ff1e..2f18f23 100644
--- a/package.json
+++ b/package.json
@@ -18,7 +18,7 @@
   "bugs": "https://github.com/leafac/kill-the-newsletter/issues",
   "homepage": "https://github.com/leafac/kill-the-newsletter#readme",
   "scripts": {
-    "start": "ts-node-dev --poll src/index.ts configuration.development.js",
+    "start": "ts-node-dev --poll src/index.ts",
     "test": "prettier --check \"src/**/*\" --end-of-line auto && jest",
     "prepare": "tsc"
   },
diff --git a/src/index.ts b/src/index.ts
index 5fc53f3..f32f93b 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -520,9 +520,20 @@ export default function killTheNewsletter(
 
 if (require.main === module) {
   console.log(`Kill the Newsletter!/${VERSION}`);
-  const configurationFile = path.resolve(
-    process.argv[2] ?? path.join(process.cwd(), "configuration.js")
-  );
-  require(configurationFile)(require);
-  console.log(`Configuration loaded from ‘${configurationFile}’.`);
+  const configurationFile = process.argv[2];
+  if (configurationFile === undefined) {
+    const { webApplication, emailApplication } = killTheNewsletter(
+      path.join(process.cwd(), "data")
+    );
+    webApplication.listen(new URL(webApplication.get("url")).port, () => {
+      console.log(`Web server started at ${webApplication.get("url")}`);
+    });
+    emailApplication.listen(new URL(webApplication.get("email")).port, () => {
+      console.log(`Email server started at ${webApplication.get("email")}`);
+    });
+  } else {
+    const configurationFileAbsolute = path.resolve(configurationFile);
+    require(configurationFileAbsolute)(require);
+    console.log(`Configuration loaded from ‘${configurationFileAbsolute}’.`);
+  }
 }