diff --git a/README.md b/README.md
index 2d3b426..837eb4d 100644
--- a/README.md
+++ b/README.md
@@ -241,6 +241,42 @@ summary
    23.28x faster than ejs.render
 ```
 
+## micro-template-serialize
+
+`micro-template-serialize` is a CLI tool for precompiling multiple template files into a single ESM (ECMAScript Module) JavaScript file. This is especially useful for environments where dynamic function generation (such as with `new Function()`) is not allowed, or for delivering precompiled templates to browsers or serverless environments.
+
+### Why use it?
+- **Security:** Avoids the use of `new Function()` at runtime, which is often restricted in secure or serverless environments.
+- **Performance:** Templates are precompiled, so rendering is fast and does not require parsing or compiling templates at runtime.
+- **Convenience:** Bundles multiple templates into a single importable module.
+
+### Usage
+
+```sh
+micro-template-serialize <input1.tmpl> <input2.tmpl> ... --output <output.js> [--root <dir>]
+```
+
+- `<input1.tmpl> ...` : List of template files to serialize.
+- `--output <output.js>` : Output JavaScript file (required).
+- `--root <dir>` : Root directory for template IDs (default: current directory).
+
+#### Example
+
+```sh
+micro-template-serialize test/data-test1.tmpl test/data-fizzbuzz.tmpl --output templates.js --root test
+```
+
+This will generate a file named `templates.js` in the current directory. You can then import the generated module in your JavaScript code:
+
+```js
+import { extended as template } from './templates.js';
+const result = template('main', { foo: 'world', baz: 'baz!' });
+console.log('render result:', result);
+```
+
+- If a template does not contain a `<!--meta.keys=[...]-->` comment, a warning will be shown.
+- The output file is an ESM module (use `import` to load it).
+
 LICENSE
 -------
 
diff --git a/bin/micro-template-serialize.js b/bin/micro-template-serialize.js
new file mode 100755
index 0000000..1373603
--- /dev/null
+++ b/bin/micro-template-serialize.js
@@ -0,0 +1,84 @@
+#!/usr/bin/env node
+
+import { serializeTemplates } from '../lib/serializer.js';
+import { promises as fs } from 'fs';
+import path from 'path';
+
+const USAGE = `
+Usage: micro-template-serialize <input1.tmpl> ... --output <output.js> [--root <dir>]
+
+Purpose:
+  Reads one or more template files, extracts their content and meta information
+  (such as keys defined in <!--meta.keys=[...]-->), and serializes them into a JavaScript file.
+  The template ID is determined by the relative path from the root directory (without extension).
+
+  This tool is especially useful for environments where dynamic function generation
+  (such as with new Function()) is not allowed, as it outputs pre-serialized ESM modules.
+
+Arguments:
+  <input1.tmpl> ...         List of template files to serialize.
+  --output <output.js>      Output JavaScript file (required).
+  --root <dir>              Root directory for template IDs (default: current directory).
+  --help, -h                Show this help message.
+
+Example:
+  micro-template-serialize test/data-test1.tmpl test/data-fizzbuzz.tmpl --output templates.js --root test
+
+  And this will generate a file named 'templates.js' in the current directory.
+  You can then import the generated module in your JavaScript code:
+
+  import { extended as template } from './templates.js';
+  const result = template('main', { foo: 'world', baz: 'baz!' });
+  console.log('render result:', result);
+
+Notes:
+  - If a template does not contain a <!--meta.keys=[...]--> comment, a warning will be shown.
+  - The output file will contain the serialized templates using the serializeTemplates function.
+  - The output file is an ESM module (use 'import' to load it).
+`;
+
+// --- 引数パース ---
+const args = process.argv.slice(2);
+if (args.includes('--help') || args.includes('-h')) {
+	console.log(USAGE);
+	process.exit(0);
+}
+let outputFile;
+let rootDir = process.cwd();
+const inputFiles = [];
+for (let i = 0; i < args.length; i++) {
+	if (args[i] === '--output') {
+		outputFile = args[++i];
+	} else
+	if (args[i] === '--root') {
+		rootDir = args[++i];
+	} else {
+		inputFiles.push(args[i]);
+	}
+}
+if (!outputFile || inputFiles.length === 0) {
+	console.error('Usage: micro-template-serialize <input1.tmpl> ... --output templates.js [--root <dir>]');
+	process.exit(1);
+}
+
+// --- テンプレートファイル読み込み ---
+const templates = {};
+for (const file of inputFiles) {
+	// id を rootDir からの相対パス（拡張子除く）にする
+	const relPath = path.relative(rootDir, file);
+	const id = relPath.replace(path.extname(relPath), '');
+	const source = await fs.readFile(file, 'utf-8');
+	templates[id] = { source };
+	source.replace(/<!--meta\.(\w+)=(.+?)-->/g, (match, key, value) => {
+		templates[id][key] = JSON.parse(value);
+		return ''; // Remove the comment
+	});
+	if (!templates[id].keys) {
+		console.warn(`Warning: Template "${id}" does not have keys defined. Please add <!--meta.keys=["key1", "key2"]--> in the template file.`);
+		templates[id].keys = [];
+	}
+}
+
+const code = serializeTemplates(templates);
+await fs.writeFile(outputFile, code);
+console.log(`Wrote: ${outputFile}`);
diff --git a/index.html b/index.html
index a214536..30d642e 100644
--- a/index.html
+++ b/index.html
@@ -166,6 +166,14 @@
 	<header>
 		<h1>micro-template.js</h1>
 		<p class="subtitle">A minimal, blazing fast JavaScript template engine for hackers.</p>
+		<div style="margin:1em 0 0.5em 0;">
+			<img src="https://img.shields.io/npm/v/micro-template.svg?style=flat-square" alt="npm version"
+				style="vertical-align:middle; margin-right:8px;">
+			<img src="https://img.shields.io/github/stars/cho45/micro-template.js?style=flat-square&label=GitHub+Stars"
+				alt="GitHub stars" style="vertical-align:middle; margin-right:8px;">
+			<img src="https://img.shields.io/npm/l/micro-template.svg?style=flat-square" alt="MIT License"
+				style="vertical-align:middle;">
+		</div>
 	</header>
 	<section class="features">
 		<h2>Features</h2>
@@ -177,16 +185,8 @@ <h2>Features</h2>
 		</ul>
 	</section>
 	<section class="usage">
-		<h2>Usage Example</h2>
+		<h2>Getting Started</h2>
 		<div class="usage-blocks">
-			<div class="usage-block">
-				<h3>Basic</h3>
-				<pre><code class="language-js">import { template } from 'micro-template';
-
-const result = template('&lt;div&gt;&lt;%= message %&gt;&lt;/div&gt;', { message: 'Hello, inline!' });
-console.log(result); // &lt;div&gt;Hello, inline!&lt;/div&gt;
-</code></pre>
-			</div>
 			<div class="usage-block">
 				<h3>In HTML</h3>
 				<pre><code class="language-html">&lt;script type="application/x-template" id="tmpl1"&gt;
@@ -200,6 +200,7 @@ <h3>In HTML</h3>
 			</div>
 			<div class="usage-block">
 				<h3>In Node.js</h3>
+				<pre><code>npm install micro-template</code></pre>
 				<pre><code class="language-js">import fs from 'node:fs';
 import { template } from 'micro-template';
 
diff --git a/lib/micro-template.js b/lib/micro-template.js
index b92496f..70c6028 100644
--- a/lib/micro-template.js
+++ b/lib/micro-template.js
@@ -6,7 +6,7 @@ const template = function (id, data) {
 	if (arguments.length < 2) throw new Error('template() must be called with (template, data)');
 	const me = template, isArray = Array.isArray(data), keys = isArray ? data : Object.keys(data || {}), key = `data:${id}:${keys.sort().join(':')}`;
 	if (!me.cache.has(key)) me.cache.set(key, (function () {
-		let name = id, string = /^[\w\-]+$/.test(id) ? me.get(id): (name = `template-${Math.random().toString(36).slice(2)}`, id); // no warnings
+		let name = id, string = /^[/\w\-]+$/.test(id) ? me.get(id): (name = `template-${Math.random().toString(36).slice(2)}`, id); // no warnings
 		let line = 1;
 		const body = (
 			`try {` +
@@ -27,8 +27,9 @@ const template = function (id, data) {
 			`//# sourceURL=${name}\n` + 
 			`//# sourceMappingURL=data:application/json,${encodeURIComponent(JSON.stringify({version:3, file:name, sources:[`${name}.ejs`], sourcesContent:[string], mappings:";;AAAA;"+Array(line-1).fill('AACA').join(';')}))}`
 		);
-		const func = new Function("__this", ...keys, body);
-		return function (stash) { return func.call(null, me.context = { escapeHTML: me.escapeHTML, line: 1, ret : '', stash: stash }, ...keys.map(key => stash[key])) };
+		const compiled = new Function("__this", ...keys, body);
+		const ret = function (stash) { return compiled.call(null, me.context = { escapeHTML: me.escapeHTML, line: 1, ret : '', stash: stash }, ...keys.map(key => stash[key])) };
+		return (ret.compiled = compiled, ret.keys = keys, ret);
 	})());
 	return isArray ? me.cache.get(key) : me.cache.get(key)(data);
 }
diff --git a/lib/serializer.js b/lib/serializer.js
new file mode 100644
index 0000000..34e0d25
--- /dev/null
+++ b/lib/serializer.js
@@ -0,0 +1,37 @@
+#!/usr/bin/env node
+
+import { template, extended } from './micro-template.js';
+
+export function serializeTemplates(target) {
+	template.get = id => target[id].source;
+	template.cache.clear();
+
+	let serialized = 'const compiled = {};\n';
+
+	for (const [id, entry] of Object.entries(target)) {
+		const keys = entry.keys || [];
+		console.log(`Compiling template: ${id}`);
+		const func = extended(id, keys);
+		const compiled = func.compiled;
+		serialized += `compiled['${id}'] = ` + compiled.toString().replace(/\/\/#.*/g, '') + ';\n';
+		serialized += `compiled['${id}'].keys = ` + JSON.stringify(func.keys) + ';\n';
+	}
+
+	serialized += `const regexp = /[<>"'&]/;\n`;
+	serialized += `const escapeHTML = ` + template.escapeHTML.toString() + ';\n';
+
+	serialized += `const template = ` + (function (id, stash) {
+		const me = template;
+		const func = compiled[id];
+		if (!func) {
+			throw new Error(`Template "${id}" not found.`);
+		}
+		return func.call(null, me.context = { escapeHTML, line: 1, ret: '', stash }, ...func.keys.map(key => stash[key]));
+	}).toString() + ';\n';
+
+	serialized += `const extended = ` + extended.toString() + ';\n';
+
+	serialized += `export { template, extended };\n`;
+
+	return serialized;
+}
diff --git a/misc/serialized.js b/misc/serialized.js
new file mode 100755
index 0000000..b324985
--- /dev/null
+++ b/misc/serialized.js
@@ -0,0 +1,5 @@
+#!/usr/bin/env node
+import { extended as template } from '../_serialized.js';
+
+const result = template('main', { foo: 'world', baz: 'baz!' });
+console.log('render result:', result);
diff --git a/package.json b/package.json
index faba2d6..a59e6e9 100644
--- a/package.json
+++ b/package.json
@@ -15,6 +15,14 @@
     "bench": "node --expose-gc ./misc/benchmark.js",
     "test:types": "npx tsc --lib es2015 --noEmit test/types.test.ts"
   },
+  "bin": {
+    "micro-template-serialize": "./bin/micro-template-serialize.js"
+  },
+  "exports": {
+    ".": "./lib/micro-template.js",
+    "./micro-template": "./lib/micro-template.js",
+    "./serializer": "./lib/serializer.js"
+  },
   "keywords": [
     "template",
     "engine",
diff --git a/test/serialize/footer.tmpl b/test/serialize/footer.tmpl
new file mode 100644
index 0000000..18a9674
--- /dev/null
+++ b/test/serialize/footer.tmpl
@@ -0,0 +1,5 @@
+<!--meta.keys=["year"] -->
+
+<footer>
+	<p>Footer content <%= year %></p>
+</footer>
diff --git a/test/serialize/main.tmpl b/test/serialize/main.tmpl
new file mode 100644
index 0000000..872f478
--- /dev/null
+++ b/test/serialize/main.tmpl
@@ -0,0 +1,11 @@
+<!--meta.keys=["foo", "baz"] -->
+
+HEADER
+<% wrapper('wrapper', function () { %>
+	hello <%= foo %>,
+	<% [1,2].forEach( () => { %>
+	and <%= baz %>
+	<% }) %>
+<% }) %>
+<% include('footer', { year: 2025 }) %>
+FOOTER
diff --git a/test/serialize/wrapper.tmpl b/test/serialize/wrapper.tmpl
new file mode 100644
index 0000000..2bfb4ba
--- /dev/null
+++ b/test/serialize/wrapper.tmpl
@@ -0,0 +1,5 @@
+<!--meta.keys=["content"] -->
+
+BEFORE CONTENT
+<%=raw content %>
+AFTER CONTENT
diff --git a/test/serializer.test.js b/test/serializer.test.js
new file mode 100644
index 0000000..d462b38
--- /dev/null
+++ b/test/serializer.test.js
@@ -0,0 +1,143 @@
+import assert from 'assert';
+import { test } from 'node:test';
+import { serializeTemplates } from '../lib/serializer.js';
+import { writeFile } from 'fs/promises';
+import { tmpdir } from 'os';
+import { join } from 'path';
+
+const templates = {
+  'main': {
+    source: 'Hello <%= name %>!',
+    keys: ['name']
+  },
+  'sub/partial': {
+    source: '<b><%= value %></b>',
+    keys: ['value']
+  }
+};
+
+test('serializeTemplates: ESM code can be imported and used', async (t) => {
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  const outFile = join(tmpdir(), 'generated-templates-' + Date.now() + '.mjs');
+  await writeFile(outFile, code);
+  const { extended: importedExtended } = await import('file://' + outFile + '?t=' + Date.now());
+  assert.strictEqual(importedExtended('main', { name: 'world' }), 'Hello world!');
+  assert.strictEqual(importedExtended('sub/partial', { value: 'X' }), '<b>X</b>');
+});
+
+test('serializeTemplates: handles empty keys and missing keys meta', async (t) => {
+  const templates = {
+    'noKeys': { source: 'foo' },
+    'emptyKeys': { source: 'bar', keys: [] },
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  const outFile = join(tmpdir(), 'generated-templates-nokeys-' + Date.now() + '.mjs');
+  await writeFile(outFile, code);
+  const { extended } = await import('file://' + outFile + '?t=' + Date.now());
+  assert.strictEqual(extended('noKeys', {}), 'foo');
+  assert.strictEqual(extended('emptyKeys', {}), 'bar');
+});
+
+test('serializeTemplates: template id is path without extension', async (t) => {
+  const templates = {
+    'foo/bar/baz': { source: 'baz', keys: [] }
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  assert.match(code, /'foo\/bar\/baz'/);
+});
+
+test('serializeTemplates: handles multiple meta comments', async (t) => {
+  const templates = {
+    'multi': {
+      source: 'foo <!--meta.keys=[\"x\"]--><!--meta.description=\"desc\"-->',
+      keys: ['x'],
+      description: 'desc'
+    }
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  assert.match(code, /description/);
+  assert.match(code, /keys/);
+});
+
+test('serializeTemplates: handles invalid meta JSON gracefully', async (t) => {
+  const templates = {
+    'invalid': {
+      source: 'foo <!--meta.keys=notjson-->',
+      keys: []
+    }
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  assert.match(code, /invalid/);
+});
+
+test('serializeTemplates: works with nested template ids', async (t) => {
+  const templates = {
+    'a/b/c': { source: 'nested', keys: [] }
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  const outFile = join(tmpdir(), 'generated-templates-nested-' + Date.now() + '.mjs');
+  await writeFile(outFile, code);
+  const { extended } = await import('file://' + outFile + '?t=' + Date.now());
+  assert.strictEqual(extended('a/b/c', {}), 'nested');
+});
+
+test('serializeTemplates: missing variable is undefined string', async (t) => {
+  const templates = {
+    'main': { source: 'Hello <%= name %>!', keys: ['name'] }
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  const outFile = join(tmpdir(), 'generated-templates-missingvar-' + Date.now() + '.mjs');
+  await writeFile(outFile, code);
+  const { extended } = await import('file://' + outFile + '?t=' + Date.now());
+  assert.strictEqual(extended('main', {}), 'Hello undefined!');
+});
+
+test('serializeTemplates: extra variables are ignored', async (t) => {
+  const templates = {
+    'main': { source: 'Hello <%= name %>!', keys: ['name'] }
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  const outFile = join(tmpdir(), 'generated-templates-extravars-' + Date.now() + '.mjs');
+  await writeFile(outFile, code);
+  const { extended } = await import('file://' + outFile + '?t=' + Date.now());
+  assert.strictEqual(extended('main', { name: 'world', foo: 'bar' }), 'Hello world!');
+});
+
+test('serializeTemplates: wrapper template renders content', async (t) => {
+  const templates = {
+    'wrapper': {
+      source: 'BEFORE CONTENT <%= content %> AFTER CONTENT',
+      keys: ['content']
+    },
+	'main': {
+	  source: 'BEFORE WRAPPER <% wrapper("wrapper", function () { %> Hello, <%= name %>! <% }) %> AFTER WRAPPER',
+	  keys: ['name']
+	}
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  const outFile = join(tmpdir(), 'generated-templates-wrapper-' + Date.now() + '.mjs');
+  await writeFile(outFile, code);
+  const { extended } = await import('file://' + outFile + '?t=' + Date.now());
+  assert.strictEqual(extended('main', { name: 'foobar' }), 'BEFORE WRAPPER BEFORE CONTENT  Hello, foobar!  AFTER CONTENT AFTER WRAPPER');
+});
+
+test('serializeTemplates: include renders template', async (t) => {
+  const templates = {
+    'other': {
+      source: '<div><%= name %></div>',
+      keys: ['name']
+    },
+    'main': {
+      source: 'BEFORE <% include("other", { name: "foobar" }) %> AFTER',
+      keys: []
+    }
+  };
+  const code = serializeTemplates(templates, { exportName: 'extended' });
+  const outFile = join(tmpdir(), 'generated-templates-include-' + Date.now() + '.mjs');
+  await writeFile(outFile, code);
+  const { extended } = await import('file://' + outFile + '?t=' + Date.now());
+  assert.strictEqual(
+    extended('main', {}),
+    'BEFORE <div>foobar</div> AFTER'
+  );
+});
diff --git a/test/test.js b/test/test.js
index 5ab93b2..7c8747a 100755
--- a/test/test.js
+++ b/test/test.js
@@ -9,14 +9,6 @@ import fs from 'fs';
 // template.get の上書き
 template.get = function (id) { return fs.readFileSync('test/data-' + id + '.tmpl', 'utf-8') };
 
-function templateWithCompiledFunction(stringTemplate, data) {
-	data = Object.assign({}, data);
-	data.__context = {};
-	stringTemplate += `\n<% __context.compiled = arguments.callee; %>`;
-	const result =  template(stringTemplate, data);
-	return [result, data.__context.compiled];
-}
-
 // --- template 基本テスト ---
 test('template renders with data', (t) => {
 	const result = template('<b><%= foo %></b><i><%= bar %></i>', { foo: 'foo', bar: 'bar' });
@@ -326,8 +318,8 @@ test('template with properties script tags', (t) => {
 });
 
 test('template output includes sourceMappingURL comment', (t) => {
-	const [_, compiledFunction] = templateWithCompiledFunction('foo bar', {});
-	const compiledFunctionString = compiledFunction.toString();
+	const func = template('foo bar', []);
+	const compiledFunctionString = func.compiled.toString();
 	console.log(compiledFunctionString);
 	const match = compiledFunctionString.match(/\n\/\/\# sourceMappingURL=data:application\/json,(.+)\n/);
 	assert(match, 'sourceMappingURL comment is present and correctly formatted');