diff --git a/.circleci/config.yml b/.circleci/config.yml
index 81bfda402..359156a75 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -3,7 +3,7 @@ version: 2
 defaults: &defaults
   working_directory: ~/repo
   docker:
-    - image: iodide/pyodide-env:9
+    - image: iodide/pyodide-env:10
   environment:
     - EMSDK_NUM_CORES: 4
       EMCC_CORES: 4
diff --git a/.gitignore b/.gitignore
index 2a6e2fa97..51156fd02 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,6 +12,7 @@ firefox/
 .vscode
 .idea
 .mypy_cache/
+node_modules/
 
 build
 downloads
diff --git a/Dockerfile b/Dockerfile
index 634db74d3..40a72c9ed 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,14 +3,10 @@ FROM python:3.8.2-buster
 RUN apt-get update \
   && apt-get install -y --no-install-recommends \
                   # building packages
-                  bzip2 ccache clang-format-6.0 cmake f2c g++ gfortran libtinfo5 node-less swig uglifyjs \
+                  bzip2 ccache clang-format-6.0 cmake f2c g++ gfortran libtinfo5 swig \
                   # testing packages: libgconf-2-4 is necessary for running chromium
                   libgconf-2-4 chromium \
-  && rm -rf /var/lib/apt/lists/* \
-  && test "Comment: Hardcode nodejs path for uglifyjs, so it doesn't conflict with emcc's nodejs" \
-  && test $(which node) = /usr/bin/node && test $(which uglifyjs) = /usr/bin/uglifyjs \
-  && echo '#!/bin/sh -e\nexec /usr/bin/node /usr/bin/uglifyjs "$@"' >/tmp/uglifyjs \
-  && chmod a+x /tmp/uglifyjs && mv -t /usr/local/bin /tmp/uglifyjs
+  && rm -rf /var/lib/apt/lists/*
 
 RUN pip3 --no-cache-dir install pytest pytest-xdist pytest-instafail pytest-rerunfailures \
       pytest-httpserver pytest-cov selenium PyYAML flake8 black distlib mypy "Cython<3.0"
diff --git a/Makefile b/Makefile
index aeca432a3..c6fe8f359 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,8 @@ include Makefile.envs
 .PHONY=check
 
 FILEPACKAGER=$(PYODIDE_ROOT)/emsdk/emsdk/fastcomp/emscripten/tools/file_packager.py
+UGLIFYJS=$(PYODIDE_ROOT)/node_modules/.bin/uglifyjs
+LESSC=$(PYODIDE_ROOT)/node_modules/.bin/lessc
 
 CPYTHONROOT=cpython
 CPYTHONLIB=$(CPYTHONROOT)/installs/python-$(PYVERSION)/lib/python$(PYMINOR)
@@ -94,8 +96,8 @@ build/console.html: src/templates/console.html
 	sed -i -e 's#{{ PYODIDE_BASE_URL }}#$(PYODIDE_BASE_URL)#g' $@
 
 
-build/renderedhtml.css: src/css/renderedhtml.less
-	lessc $< $@
+build/renderedhtml.css: src/css/renderedhtml.less $(LESSC)
+	$(LESSC) $< $@
 
 build/webworker.js: src/webworker.js
 	cp $< $@
@@ -129,6 +131,7 @@ clean:
 	rm -fr root
 	rm -fr build/*
 	rm -fr src/*.bc
+	rm -fr node_modules
 	make -C packages clean
 	make -C packages/six clean
 	make -C packages/jedi clean
@@ -157,9 +160,12 @@ build/test.data: $(CPYTHONLIB)
 		cd build; \
 		python $(FILEPACKAGER) test.data --lz4 --preload ../$(CPYTHONLIB)/test@/lib/python3.8/test --js-output=test.js --export-name=pyodide._module --exclude __pycache__ \
 	)
-	uglifyjs build/test.js -o build/test.js
+	$(UGLIFYJS) build/test.js -o build/test.js
 
 
+$(UGLIFYJS) $(LESSC): emsdk/emsdk/.complete
+	npm i --no-save uglify-js lessc
+
 root/.built: \
 		$(CPYTHONLIB) \
 		$(SIX_LIBS) \
diff --git a/Makefile.envs b/Makefile.envs
index 0d8858579..b0e913e5e 100644
--- a/Makefile.envs
+++ b/Makefile.envs
@@ -1,7 +1,7 @@
 export EMSCRIPTEN_VERSION = 1.38.44
 export BINARYEN_VERSION = version_86
 
-export PATH := $(PYODIDE_ROOT)/ccache:$(PYODIDE_ROOT)/emsdk/emsdk:$(PYODIDE_ROOT)/emsdk/emsdk/node/12.18.1_64bit/bin:$(PYODIDE_ROOT)/emsdk/emsdk/binaryen/bin/:$(PYODIDE_ROOT)/emsdk/emsdk/fastcomp/emscripten/:$(PATH)
+export PATH := $(PYODIDE_ROOT)/ccache:$(PYODIDE_ROOT)/emsdk/emsdk:$(PYODIDE_ROOT)/emsdk/emsdk/node/12.18.1_64bit/bin:$(PYODIDE_ROOT)/emsdk/emsdk/binaryen/bin/:$(PYODIDE_ROOT)/emsdk/emsdk/fastcomp/emscripten/:$(PYODIDE_ROOT)/node_modules/.bin/:$(PATH)
 
 export EMSDK = $(PYODIDE_ROOT)/emsdk/emsdk
 export EM_CONFIG = $(PYODIDE_ROOT)/emsdk/emsdk/.emscripten
diff --git a/docs/building_from_sources.md b/docs/building_from_sources.md
index 486b6960a..58baf8f2e 100644
--- a/docs/building_from_sources.md
+++ b/docs/building_from_sources.md
@@ -19,8 +19,6 @@ Additional build prerequisites are:
 - PyYAML
 - FreeType 2 development libraries to compile Matplotlib.
 - Cython to compile SciPy
-- [lessc](http://lesscss.org/) to compile less to css.
-- [uglifyjs](https://github.com/mishoo/UglifyJS) to minify Javascript builds.
 - gfortran (GNU Fortran 95 compiler)
 - [f2c](http://www.netlib.org/f2c/)
 - [ccache](https://ccache.samba.org) (optional) *highly* recommended for much faster rebuilds.
diff --git a/docs/changelog.md b/docs/changelog.md
index 4bbee4b08..80ed5a70c 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -19,6 +19,7 @@
 
 ### Added
 - `micropip` now supports installing wheels from relative urls. [#872](https://github.com/iodide-project/pyodide/pull/872)
+- uglifyjs and lessc no longer need to be installed in the system during build
 
 ## Version 0.16.1
 *December 25, 2020*
diff --git a/run_docker b/run_docker
index c1c9da205..0ce40d699 100755
--- a/run_docker
+++ b/run_docker
@@ -26,7 +26,7 @@ function error() {
 }
 
 
-PYODIDE_IMAGE_TAG="9"
+PYODIDE_IMAGE_TAG="10"
 PYODIDE_PREBUILT_IMAGE_TAG="0.16.0b1"
 DEFAULT_PYODIDE_DOCKER_IMAGE="iodide/pyodide-env:${PYODIDE_IMAGE_TAG}"
 DEFAULT_PYODIDE_SYSTEM_PORT="8000"
diff --git a/tools/dependency-check.sh b/tools/dependency-check.sh
index 9f4787e54..6e4068ebd 100755
--- a/tools/dependency-check.sh
+++ b/tools/dependency-check.sh
@@ -37,11 +37,6 @@ check_fortran_dependencies() {
   check_binary_present "f2c"
 }
 
-check_js_dependencies() {
-  check_binary_present "lessc"
-  check_binary_present "uglifyjs"
-}
-
 check_pyyaml() {
   local pyyaml_import_check
   pyyaml_import_check="$(python3 -c 'import yaml' 2>&1)"
@@ -54,5 +49,4 @@ check_python_version
 check_pkgconfig
 #check_python_headers
 check_fortran_dependencies
-check_js_dependencies
 check_pyyaml