diff --git a/src/js/dev/index.html b/src/js/dev/index.html
index 4afd5179..3420dd90 100644
--- a/src/js/dev/index.html
+++ b/src/js/dev/index.html
@@ -1,4 +1,4 @@
-<script src="./test.js" href="./test.ts" type="module"></script>
+<script src="./index.js" href="./index.ts" type="module"></script>
 <style>
   html {
     font-family: sans-serif;
diff --git a/src/js/dev/index.ts b/src/js/dev/index.ts
new file mode 100644
index 00000000..0e0ab668
--- /dev/null
+++ b/src/js/dev/index.ts
@@ -0,0 +1,3 @@
+import { workerURL } from "./worker";
+
+new Worker(workerURL, { type: "module" });
diff --git a/src/js/dev/test.ts b/src/js/dev/test.ts
deleted file mode 100644
index 005dd451..00000000
--- a/src/js/dev/test.ts
+++ /dev/null
@@ -1,32 +0,0 @@
-import { cube3x3x3 } from "cubing/puzzles";
-import { setKPuzzleDefString, solveState, serializeDefToTws } from "..";
-
-(async () => {
-  await setKPuzzleDefString(
-    serializeDefToTws(await cube3x3x3.kpuzzle(), {
-      moveSubset: ["U", "L", "F", "R", "B", "D"],
-      startState: `EDGES
-0 0 0 0 1 2 3 4 5 6 7 8
-0 0 0 0 0 0 0 0 0 0 0 0
-CORNERS
-0 0 0 0 1 2 3 4
-0 0 0 0 0 0 0 0
-CENTERS
-0 1 2 3 4 5
-0 0 0 0 0 0`,
-    }),
-  );
-  (
-    await solveState(`ScrambleState test
-EDGES
-0 0 0 0 1 2 3 4 5 6 7 8
-1 1 1 1 0 0 0 0 0 0 0 0
-CORNERS
-0 0 0 0 1 2 3 4
-0 0 0 0 0 0 0 0
-CENTERS
-0 1 2 3 4 5
-0 0 0 0 0 0
-End`)
-  ).log();
-})();
diff --git a/src/js/dev/worker.ts b/src/js/dev/worker.ts
new file mode 100644
index 00000000..56b8cfa5
--- /dev/null
+++ b/src/js/dev/worker.ts
@@ -0,0 +1,39 @@
+// TODO: remove once `esbuild` supports relative URLs: https://github.com/evanw/esbuild/pull/2508
+export const workerURL = import.meta.url;
+
+if (globalThis.WorkerGlobalScope) {
+  (async () => {
+    const [
+      { cube3x3x3 },
+      { setKPuzzleDefString, solveState, serializeDefToTws },
+    ] = await Promise.all([import("cubing/puzzles"), import("..")]);
+
+    await setKPuzzleDefString(
+      serializeDefToTws(await cube3x3x3.kpuzzle(), {
+        moveSubset: ["U", "L", "F", "R", "B", "D"],
+        startState: `EDGES
+  0 0 0 0 1 2 3 4 5 6 7 8
+  0 0 0 0 0 0 0 0 0 0 0 0
+  CORNERS
+  0 0 0 0 1 2 3 4
+  0 0 0 0 0 0 0 0
+  CENTERS
+  0 1 2 3 4 5
+  0 0 0 0 0 0`,
+      }),
+    );
+    (
+      await solveState(`ScrambleState test
+  EDGES
+  0 0 0 0 1 2 3 4 5 6 7 8
+  1 1 1 1 0 0 0 0 0 0 0 0
+  CORNERS
+  0 0 0 0 1 2 3 4
+  0 0 0 0 0 0 0 0
+  CENTERS
+  0 1 2 3 4 5
+  0 0 0 0 0 0
+  End`)
+    ).log();
+  })();
+}