diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 851d7ace4c..9e65f65ecc 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -38,7 +38,7 @@ As of Dash 1.2, the renderer bundle and its peer dependencies can be packed and
 3.  `renderer bundles` parses the locked version JSON, copies all the peer dependencies into dash_renderer folder, bundles the renderer assets, and generates an `__init__.py` to map all the resources. There are also a list of helpful `scripts` property defined in `package.json` you might need to do some handy tasks like linting, syntax format with prettier, etc.
 4.  `renderer digest` computes the content hash of each asset in `dash_renderer` folder, prints out the result in logs, and dumps into a JSON file `digest.json`. Use this when you have a doubt about the current assets in `dash_renderer`, and compare it with previous result in one shot by this command.
 5.  `renderer build` runs 1, 2, 3, 4 in sequence as a complete build process from scratch.
-6.  `renderer watch` runs the webpack in watch mode, so any source code change triggers a rebuild. Use this if you are actively updating renderer code and you want to test your changes immediately.
+6.  `renderer build local` runs the same order as in 5 and also generates source maps for debugging purposes. You also need to install dash-renderer with editable mode: `pip install -e .`.
 
 When a change in renderer code doesn't reflect in your browser as expected, this could be: confused bundle generation, caching issue in a browser, python package not in `editable` mode, etc. The new tool reduces the risk of bundle assets by adding the digest to help compare asset changes.
 
diff --git a/dash-renderer/CHANGELOG.md b/dash-renderer/CHANGELOG.md
index 1830839ca5..1bbf221264 100644
--- a/dash-renderer/CHANGELOG.md
+++ b/dash-renderer/CHANGELOG.md
@@ -2,6 +2,11 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## Unreleased
+
+### Fixed
+- Reduced about 55% of the dash-renderer packages size on **PyPI** by removing the source maps. To do more advanced debugging, the source maps needs to be generated from source code with `npm run build:local` and pip install in editable mode, i.e. `pip install -e .` [#910](https://github.com/plotly/dash/pull/910)
+
 ## [1.0.1] - 2019-08-27
 - Clean all the binary assets in dash-renderer repo, add tool to build all the required bundles from fresh source code to avoid confusion of the assets and improve the release process. [#874](https://github.com/plotly/dash/pull/874)
 
diff --git a/dash-renderer/MANIFEST.in b/dash-renderer/MANIFEST.in
index b17522ced4..0c9ca09a82 100644
--- a/dash-renderer/MANIFEST.in
+++ b/dash-renderer/MANIFEST.in
@@ -1,4 +1,4 @@
 include package.json
 include digest.json
 include dash_renderer/*.js
-include dash_renderer/*.map
+exclude dash_renderer/*.map
diff --git a/dash-renderer/init.template b/dash-renderer/init.template
index 17d90ca57f..c92708ec3c 100644
--- a/dash-renderer/init.template
+++ b/dash-renderer/init.template
@@ -45,8 +45,6 @@ _js_dist = [
     {
         "relative_package_path": "{}.min.js.map".format(__name__),
         "dev_package_path": "{}.dev.js.map".format(__name__),
-        "external_url": "https://unpkg.com/dash-renderer@$version"
-        "/dash_renderer/dash_renderer.min.js.map",
         "namespace": "dash_renderer",
         "dynamic": True,
     },
diff --git a/dash-renderer/package.json b/dash-renderer/package.json
index 549f5961a8..6cf410bd5f 100644
--- a/dash-renderer/package.json
+++ b/dash-renderer/package.json
@@ -6,8 +6,9 @@
   "scripts": {
     "lint": "./node_modules/.bin/eslint --quiet --fix .",
     "lint:test": "./node_modules/.bin/eslint .",
-    "build:js": "webpack --mode development && webpack --mode production",
-    "build:dev": "webpack --mode development --watch",
+    "build:js": "webpack --build release",
+    "build:dev": "webpack --build local",
+    "build:local": "renderer build local",
     "build": "renderer build",
     "start": "webpack-serve ./webpack.serve.config.js",
     "format": "prettier --config .prettierrc --write \"src/**/*.js\"",
diff --git a/dash-renderer/webpack.config.js b/dash-renderer/webpack.config.js
index 31069b8eb1..81f1bda7cf 100644
--- a/dash-renderer/webpack.config.js
+++ b/dash-renderer/webpack.config.js
@@ -1,87 +1,84 @@
 const webpack = require('webpack');
+const R = require('ramda');
 const path = require('path');
 const packagejson = require('./package.json');
-
 const dashLibraryName = packagejson.name.replace(/-/g, '_');
 
-module.exports = (env, argv) => {
-    let mode;
-
-    // if user specified mode flag take that value
-    if (argv && argv.mode) {
-        mode = argv.mode;
-    }
-
-    // else if configuration object is already set (module.exports) use that value
-    else if (module.exports && module.exports.mode) {
-        mode = module.exports = mode;
-    }
-
-    // else take webpack default
-    else {
-        mode = 'production';
-    }
-    return {
-        entry: {main: ['@babel/polyfill', 'whatwg-fetch', './src/index.js']},
-        output: {
-            path: path.resolve(__dirname, dashLibraryName),
-            filename:
-                mode === 'development'
-                    ? `${dashLibraryName}.dev.js`
-                    : `${dashLibraryName}.min.js`,
-            library: dashLibraryName,
-            libraryTarget: 'window',
-        },
-        devtool: 'source-map',
-        externals: {
-            react: 'React',
-            'react-dom': 'ReactDOM',
-            'plotly.js': 'Plotly',
-            'prop-types': 'PropTypes'
-        },
-        module: {
-            rules: [
-                {
-                    test: /\.js$/,
-                    exclude: /node_modules/,
-                    use: {
-                        loader: 'babel-loader',
-                    },
-                },
-                {
-                    test: /\.css$/,
-                    use: [
-                        {
-                            loader: 'style-loader',
-                        },
-                        {
-                            loader: 'css-loader',
-                        },
-                    ],
+const defaultOptions = {
+    mode: 'development',
+    devtool: 'none',
+    entry: {
+        main: ['@babel/polyfill', 'whatwg-fetch', './src/index.js'],
+    },
+    output: {
+        path: path.resolve(__dirname, dashLibraryName),
+        filename: `${dashLibraryName}.dev.js`,
+        library: dashLibraryName,
+        libraryTarget: 'window',
+    },
+    externals: {
+        react: 'React',
+        'react-dom': 'ReactDOM',
+        'plotly.js': 'Plotly',
+        'prop-types': 'PropTypes',
+    },
+    plugins: [],
+    module: {
+        rules: [
+            {
+                test: /\.js$/,
+                exclude: /node_modules/,
+                use: {
+                    loader: 'babel-loader',
                 },
-                {
-                    test: /\.svg$/,
-                    use: ['@svgr/webpack']
-                },
-                {
-                    test: /\.txt$/i,
-                    use: 'raw-loader',
+            },
+            {
+                test: /\.css$/,
+                use: [
+                    {
+                        loader: 'style-loader',
+                    },
+                    {
+                        loader: 'css-loader',
+                    },
+                ],
+            },
+            {
+                test: /\.svg$/,
+                use: ['@svgr/webpack'],
+            },
+            {
+                test: /\.txt$/i,
+                use: 'raw-loader',
+            },
+        ],
+    },
+};
 
+module.exports = (_, argv) => {
+    const devtool = argv.build === 'local' ? 'source-map' : 'none';
+    return [
+        R.mergeDeepLeft({devtool}, defaultOptions),
+        R.mergeDeepLeft(
+            {
+                devtool: devtool,
+                mode: 'production',
+                output: {
+                    filename: `${dashLibraryName}.min.js`,
                 },
-            ],
-        },
-        plugins: [
-            new webpack.NormalModuleReplacementPlugin(
-                /(.*)GlobalErrorContainer.react(\.*)/,
-                function(resource) {
-                    if (mode === 'production') {
-                        resource.request = resource.request.replace(
-                            /GlobalErrorContainer.react/,
-                            'GlobalErrorContainerPassthrough.react'
-                        );
-                    }
-                }
-            ),
-        ],
-    };
+                plugins: [
+                    new webpack.NormalModuleReplacementPlugin(
+                        /(.*)GlobalErrorContainer.react(\.*)/,
+                        function(resource) {
+                            resource.request = resource.request.replace(
+                                /GlobalErrorContainer.react/,
+                                'GlobalErrorContainerPassthrough.react'
+                            );
+                        }
+                    ),
+                ],
+            },
+            defaultOptions
+        ),
+    ];
 };
diff --git a/dash/development/build_process.py b/dash/development/build_process.py
index e1e7565a50..9745dbf8f3 100644
--- a/dash/development/build_process.py
+++ b/dash/development/build_process.py
@@ -77,10 +77,10 @@ def watch(self):
         os.system("npm run build:dev")
 
     @job("run the whole building process in sequence")
-    def build(self):
+    def build(self, build=None):
         self.clean()
         self.npm()
-        self.bundles()
+        self.bundles(build)
         self.digest()
 
     @job("compute the hash digest for assets")
@@ -108,7 +108,7 @@ def digest(self):
         )
 
     @job("copy and generate the bundles")
-    def bundles(self):
+    def bundles(self, build=None):
         if not os.path.exists(self.build_folder):
             try:
                 os.makedirs(self.build_folder)
@@ -142,9 +142,10 @@ def bundles(self):
                 self._concat(self.build_folder, target),
             )
 
-        logger.info("run `npm run build:js`")
+        _script = 'build:dev' if build == 'local' else 'build:js'
+        logger.info("run `npm run %s`", _script)
         os.chdir(self.main)
-        run_command_with_process("npm run build:js")
+        run_command_with_process("npm run {}".format(_script))
 
         logger.info("generate the `__init__.py` from template and verisons")
         with open(self._concat(self.main, "init.template")) as fp: