diff --git a/pyscript.core/.eslintrc.json b/pyscript.core/.eslintrc.json
index 6d5c3787..66c656ce 100644
--- a/pyscript.core/.eslintrc.json
+++ b/pyscript.core/.eslintrc.json
@@ -8,5 +8,6 @@
         "ecmaVersion": 12,
         "sourceType": "module"
     },
+    "ignorePatterns": ["__template.js"],
     "rules": {}
 }
diff --git a/pyscript.core/.gitignore b/pyscript.core/.gitignore
index 3150ddba..1b2dc421 100644
--- a/pyscript.core/.gitignore
+++ b/pyscript.core/.gitignore
@@ -5,4 +5,5 @@ cjs/
 !cjs/package.json
 core.js
 esm/worker/xworker.js
+esm/worker/__template.js
 types/
diff --git a/pyscript.core/.npmignore b/pyscript.core/.npmignore
index 686fd10a..c5cc42aa 100644
--- a/pyscript.core/.npmignore
+++ b/pyscript.core/.npmignore
@@ -16,4 +16,6 @@ node.importmap
 sw.js
 tsconfig.json
 cjs/worker/_template.js
+cjs/worker/__template.js
 esm/worker/_template.js
+esm/worker/__template.js
diff --git a/pyscript.core/README.md b/pyscript.core/README.md
index 88fdc748..a69279fe 100644
--- a/pyscript.core/README.md
+++ b/pyscript.core/README.md
@@ -43,3 +43,7 @@ NO_MIN=1 npm run build
 
 npm run server
 ```
+
+### Dev Build
+
+Beside spinning the _localhost_ server via `npm run server`, the `npm run dev` will watch changes in the `./esm` folder and it will build automatically non optimized artifacts out of the box.
diff --git a/pyscript.core/dev.cjs b/pyscript.core/dev.cjs
new file mode 100644
index 00000000..04fd1919
--- /dev/null
+++ b/pyscript.core/dev.cjs
@@ -0,0 +1,33 @@
+let queue = Promise.resolve();
+
+const { exec } = require("node:child_process");
+
+const build = (fileName) => {
+    if (fileName) console.log(fileName, "changed");
+    else console.log("building without optimizations");
+    queue = queue.then(
+        () =>
+            new Promise((resolve, reject) => {
+                exec(
+                    "npm run rollup:xworker && npm run rollup:core && npm run rollup:pyscript",
+                    { cwd: __dirname, env: { ...process.env, NO_MIN: true } },
+                    (error) => {
+                        if (error) reject(error);
+                        else
+                            resolve(
+                                console.log(fileName || "", "build completed"),
+                            );
+                    },
+                );
+            }),
+    );
+};
+
+const options = {
+    ignored: /\/(?:__template|interpreters|xworker)\.[mc]?js$/,
+    persistent: true,
+};
+
+require("chokidar").watch("./esm", options).on("change", build);
+
+build();
diff --git a/pyscript.core/package.json b/pyscript.core/package.json
index af8241bc..6b7107ca 100644
--- a/pyscript.core/package.json
+++ b/pyscript.core/package.json
@@ -8,6 +8,7 @@
         "server": "npx static-handler --cors --coep --coop --corp .",
         "build": "npm run rollup:xworker && npm run rollup:core && npm run rollup:pyscript && eslint esm/ && npm run ts && npm run cjs && npm run test",
         "cjs": "ascjs --no-default esm cjs",
+        "dev": "node dev.cjs",
         "rollup:core": "rollup --config rollup/core.config.js",
         "rollup:pyscript": "rollup --config rollup/pyscript.config.js",
         "rollup:xworker": "rollup --config rollup/xworker.config.js",
@@ -32,6 +33,7 @@
         "@rollup/plugin-terser": "^0.4.3",
         "ascjs": "^5.0.1",
         "c8": "^8.0.0",
+        "chokidar": "^3.5.3",
         "eslint": "^8.43.0",
         "linkedom": "^0.14.26",
         "rollup": "^3.25.3",
@@ -64,6 +66,6 @@
         "coincident": "^0.8.3"
     },
     "worker": {
-        "blob": "sha256-CaHDEAEttvghrbLR/GVAofT+zQZyy0Ri9tkpVTNBbiE="
+        "blob": "sha256-eWNZbyS06lxxlUW/bkU7/fl/Levxxxfiv/+frsgl/fA="
     }
 }
diff --git a/pyscript.core/rollup/build_xworker.cjs b/pyscript.core/rollup/build_xworker.cjs
index 646da781..b48a2cbd 100644
--- a/pyscript.core/rollup/build_xworker.cjs
+++ b/pyscript.core/rollup/build_xworker.cjs
@@ -13,18 +13,28 @@ const PACKAGE_JSON = resolve(join(__dirname, "..", "package.json"));
 
 for (const file of readdirSync(WORKERS_DIR)) {
     if (file.startsWith("__")) {
-        const js = JSON.stringify(
-            readFileSync(join(WORKERS_DIR, file)).toString(),
-        );
-        const hash = createHash("sha256");
-        hash.update(js);
-        const json = require(PACKAGE_JSON);
-        json.worker = { blob: "sha256-" + hash.digest("base64") };
-        writeFileSync(PACKAGE_JSON, JSON.stringify(json, null, "    ") + "\n");
-        writeFileSync(
-            join(WORKERS_DIR, "xworker.js"),
-            `/* c8 ignore next */\nexport default () => new Worker(URL.createObjectURL(new Blob([${js}],{type:'application/javascript'})),{type:'module'});`,
-        );
-        rmSync(join(WORKERS_DIR, file));
+        if (process.env.NO_MIN) {
+            writeFileSync(
+                join(WORKERS_DIR, "xworker.js"),
+                `/* c8 ignore next */\nexport default () => new Worker('/esm/worker/__template.js',{type:'module'});`,
+            );
+        } else {
+            const js = JSON.stringify(
+                readFileSync(join(WORKERS_DIR, file)).toString(),
+            );
+            const hash = createHash("sha256");
+            hash.update(js);
+            const json = require(PACKAGE_JSON);
+            json.worker = { blob: "sha256-" + hash.digest("base64") };
+            writeFileSync(
+                PACKAGE_JSON,
+                JSON.stringify(json, null, "    ") + "\n",
+            );
+            writeFileSync(
+                join(WORKERS_DIR, "xworker.js"),
+                `/* c8 ignore next */\nexport default () => new Worker(URL.createObjectURL(new Blob([${js}],{type:'application/javascript'})),{type:'module'});`,
+            );
+            rmSync(join(WORKERS_DIR, file));
+        }
     }
 }