diff --git a/.gitignore b/.gitignore
index 930c8dc863..dbed468f15 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,10 +3,10 @@
 node_modules
 *.map
 /cli/
-/compiler/
-/ssr/
-/internal.js
 /compiler.js
+/index.js
+/internal.*
+/store.js
 /scratch/
 /coverage/
 /coverage.lcov/
@@ -15,7 +15,6 @@ node_modules
 /test/sourcemaps/samples/*/output.js.map
 /test/sourcemaps/samples/*/output.css
 /test/sourcemaps/samples/*/output.css.map
-/store.umd.js
 /yarn-error.log
 _actual*.*
-_*/
\ No newline at end of file
+_*/
diff --git a/index.js b/index.mjs
similarity index 77%
rename from index.js
rename to index.mjs
index 9fdeadb8fa..44031c35c8 100644
--- a/index.js
+++ b/index.mjs
@@ -4,4 +4,4 @@ export {
 	beforeUpdate,
 	afterUpdate,
 	createEventDispatcher
-} from './internal.js';
+} from './internal';
diff --git a/package.json b/package.json
index 4844644834..f12c429aa9 100644
--- a/package.json
+++ b/package.json
@@ -2,6 +2,7 @@
   "name": "svelte",
   "version": "3.0.0-alpha6",
   "description": "The magical disappearing UI framework",
+  "module": "index.mjs",
   "main": "index.js",
   "bin": {
     "svelte": "svelte"
@@ -10,9 +11,9 @@
     "cli",
     "compiler.js",
     "register.js",
-    "index.js",
-    "internal.js",
-    "store.js",
+    "index.*",
+    "internal.*",
+    "store.*",
     "svelte",
     "README.md"
   ],
diff --git a/rollup.config.js b/rollup.config.js
index 3229a2800f..1bb01c9282 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -1,14 +1,12 @@
-import path from 'path';
 import replace from 'rollup-plugin-replace';
 import resolve from 'rollup-plugin-node-resolve';
 import commonjs from 'rollup-plugin-commonjs';
 import json from 'rollup-plugin-json';
 import typescript from 'rollup-plugin-typescript';
-import buble from 'rollup-plugin-buble';
 import pkg from './package.json';
 
 export default [
-	/* compiler/svelte.js */
+	/* compiler.js */
 	{
 		input: 'src/index.ts',
 		plugins: [
@@ -54,12 +52,38 @@ export default [
 		experimentalCodeSplitting: true
 	},
 
-	/* internal.js */
+	/* index.js */
+	{
+		input: 'index.mjs',
+		output: {
+			file: 'index.js',
+			format: 'cjs'
+		},
+		external: name => name !== 'index.mjs'
+	},
+
+	/* internal.[m]js */
 	{
 		input: 'src/internal/index.js',
+		output: [
+			{
+				file: 'internal.mjs',
+				format: 'esm'
+			},
+			{
+				file: 'internal.js',
+				format: 'cjs'
+			}
+		]
+	},
+
+	/* store.js */
+	{
+		input: 'store.mjs',
 		output: {
-			file: 'internal.js',
-			format: 'es'
-		}
-	}
+			file: 'store.js',
+			format: 'cjs'
+		},
+		external: name => name !== 'store.mjs'
+	},
 ];
diff --git a/store.js b/store.mjs
similarity index 97%
rename from store.js
rename to store.mjs
index d22afdedee..ffdd90bf0e 100644
--- a/store.js
+++ b/store.mjs
@@ -1,4 +1,4 @@
-import { run_all, noop } from './internal.js';
+import { run_all, noop } from './internal';
 
 export function readable(start, value) {
 	const subscribers = [];