diff --git a/build.mjs b/build.mjs
new file mode 100644
index 0000000..895f5da
--- /dev/null
+++ b/build.mjs
@@ -0,0 +1,9 @@
+import { build } from "esbuild";
+await build({
+  entryPoints: ["src/background.js"],
+  bundle: true,
+  format: "esm",
+  platform: "browser",
+  target: "chrome120",
+  outfile: "extension/background.js"
+});