The Servo Browser Engine
Latest commit e888b76 Oct 26, 2016 @bors-servo bors-servo committed on GitHub Auto merge of #13923 - pcwalton:inline-absolute-hypothetical-margin, …

layout: Remove margins from inline absolute hypothetical boxes.

As they're hypothetical, their margins shouldn't take up space!

Improves Google search results.

Closes #13915.

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components Auto merge of #13923 - pcwalton:inline-absolute-hypothetical-margin, … Oct 26, 2016
docs Auto merge of #13469 - JanZerebecki:document-cargo-update-precise, r=… Sep 30, 2016
etc Restore the layout trace viewer Oct 17, 2016
ports Auto merge of #13913 - bholley:styling_mode, r=emilio Oct 26, 2016
python Fix style unit tests Oct 18, 2016
resources Update WR - texture layers, image mask, profiler, optimizations. Oct 26, 2016
support WebBluetooth Android support Sep 6, 2016
tests Auto merge of #13923 - pcwalton:inline-absolute-hypothetical-margin, … Oct 26, 2016
.gitattributes Appease Github's Linguist Jun 11, 2015
.gitignore Move ports/geckolib/target to target/geckolib Jul 8, 2016
.travis.yml Remove test-geckolib, run test-stylo on travis Oct 12, 2016 Start collecting documentation, and add an in-tree glossary. Encourag… Apr 18, 2016
Info.plist Don't warn about reopening a crashed Servo window on Mac Jul 6, 2016
LICENSE Add license Apr 4, 2013 Avoid a common formatting problem in pull requests Aug 8, 2016 readme: List yasm as a build-time dependency for Servo. Oct 24, 2016
appveyor.yml Fix Appveyor Sep 23, 2016
cargo-nightly-build Update to Rust 1.14.0-nightly (19ac57926 2016-10-08) Oct 9, 2016
mach Minor cleanup of mach and bootstrap script Sep 1, 2016
mach.bat Windows MSVC: Define vcvars in mach.bat Aug 22, 2016
rust-nightly-date Update to Rust 1.14.0-nightly (19ac57926 2016-10-08) Oct 9, 2016
rust-stable-version Update rust-stable-version to 1.12. Oct 14, 2016
servo-tidy.toml Vendor m-c's nsstring in-tree Oct 12, 2016
servobuild.example Remove the gonk port May 28, 2016

The Servo Parallel Browser Engine Project

Linux Build Status Windows Build Status

Servo is a prototype web browser engine written in the Rust language. It is currently developed on 64bit OS X, 64bit Linux, and Android.

Servo welcomes contribution from everyone. See and for help getting started.

Visit the Servo Project page for news and guides.

Setting up your environment

Please select your operating system:


On OS X (homebrew)

brew install automake pkg-config python cmake yasm
pip install virtualenv

On OS X (MacPorts)

sudo port install python27 py27-virtualenv cmake yasm

On OS X >= 10.11 (El Capitan), you also have to install OpenSSL

brew install openssl

export OPENSSL_INCLUDE_DIR="$(brew --prefix openssl)/include"
export OPENSSL_LIB_DIR="$(brew --prefix openssl)/lib"

./mach build ...

If you've already partially compiled servo but forgot to do this step, run ./mach clean, set the shell variables, and recompile.

On Debian-based Linuxes

sudo apt-get install git curl freeglut3-dev autoconf \
    libfreetype6-dev libgl1-mesa-dri libglib2.0-dev xorg-dev \
    gperf g++ build-essential cmake virtualenv python-pip \
    libssl-dev libbz2-dev libosmesa6-dev libxmu6 libxmu-dev \
    libglu1-mesa-dev libgles2-mesa-dev libegl1-mesa-dev libdbus-1-dev

If you are on Ubuntu 14.04 and encountered errors on installing these dependencies involving libcheese, see #6158 for a workaround.

If virtualenv does not exist, try python-virtualenv.

On Fedora

sudo dnf install curl freeglut-devel libtool gcc-c++ libXi-devel \
    freetype-devel mesa-libGL-devel mesa-libEGL-devel glib2-devel libX11-devel libXrandr-devel gperf \
    fontconfig-devel cabextract ttmkfdir python python-virtualenv python-pip expat-devel \
    rpm-build openssl-devel cmake bzip2-devel libXcursor-devel libXmu-devel mesa-libOSMesa-devel \

On openSUSE Linux

sudo zypper install libX11-devel libexpat-devel libbz2-devel Mesa-libEGL-devel Mesa-libGL-devel cabextract cmake \
    dbus-1-devel fontconfig-devel freetype-devel gcc-c++ git glib2-devel gperf \
    harfbuzz-devel libOSMesa-devel libXcursor-devel libXi-devel libXmu-devel libXrandr-devel libopenssl-devel \
    python-pip python-virtualenv rpm-build glu-devel

On Arch Linux

sudo pacman -S --needed base-devel git python2 python2-virtualenv python2-pip mesa cmake bzip2 libxmu glu pkg-config

On Gentoo Linux

sudo emerge net-misc/curl media-libs/freeglut \
    media-libs/freetype media-libs/mesa dev-util/gperf \
    dev-python/virtualenv dev-python/pip dev-libs/openssl \
    x11-libs/libXmu media-libs/glu x11-base/xorg-server

On Windows MSVC

Install Git for Windows ( DO allow it to add git.exe to the PATH (default settings for the installer are fine).

Install Visual Studio 2015 Community Edition ( You MUST add "Visual C++" to the list of installed components. It is not on by default.

Install Python for Windows ( The windows x86-64 MSI installer is fine. You should change the installation to install the "Add python.exe to Path" feature.

Install virtualenv.

In a normal Windows Shell (cmd.exe or "Command Prompt" from the start menu), do:

pip install virtualenv

If this does not work, you may need to reboot for the changed PATH settings (by the python installer) to take effect.

On Windows mingw

Download Python for Windows here. This is required for the SpiderMonkey build on Windows.

Install MSYS2 from here. After you have done so, open an MSYS shell window and update the core libraries and install new packages. The extra step at the end is to downgrade GCC to 5.4, as the GCC6 versions in mingw currently fail to compile some of our dependencies. We are upgrading to a gcc-free build on Windows as soon as possible:

pacman -Su
pacman -Sy git mingw-w64-x86_64-toolchain mingw-w64-x86_64-freetype \
    mingw-w64-x86_64-icu mingw-w64-x86_64-nspr mingw-w64-x86_64-ca-certificates \
    mingw-w64-x86_64-expat mingw-w64-x86_64-cmake tar diffutils patch \
    patchutils make python2-setuptools
export GCC_URL=
export GCC_EXT=5.4.0-1-any.pkg.tar.xz
pacman -U --noconfirm $GCC_URL-$GCC_EXT $GCC_URL-ada-$GCC_EXT \
    $GCC_URL-fortran-$GCC_EXT $GCC_URL-libgfortran-$GCC_EXT $GCC_URL-libs-$GCC_EXT \
easy_install-2.7 pip virtualenv

Open a new MSYS shell window as Administrator and remove the Python binaries (they are not compatible with our mach driver script yet, unfortunately):

cd /mingw64/bin
mv python2.exe python2-mingw64.exe
mv python2.7.exe python2.7-mingw64.exe

Now, open a MINGW64 (not MSYS!) shell window, and you should be able to build servo as usual!

Cross-compilation for Android

Pre-installed Android tools are needed. See wiki for details

The Rust compiler

Servo's build system automatically downloads a Rust compiler to build itself. This is normally a specific revision of Rust upstream, but sometimes has a backported patch or two. If you'd like to know which nightly build of Rust we use, see rust-nightly-date.


Servo is built with Cargo, the Rust package manager. We also use Mozilla's Mach tools to orchestrate the build and other tasks.

Normal build

To build Servo in development mode. This is useful for development, but the resulting binary is very slow.

git clone
cd servo
./mach build --dev
./mach run tests/html/about-mozilla.html

Or on Windows MSVC, in a normal Command Prompt (cmd.exe):

git clone
cd servo
mach.bat build --dev

For benchmarking, performance testing, or real-world use, add the --release flag to create an optimized build:

./mach build --release
./mach run --release tests/html/about-mozilla.html

Building for Android target

git clone
cd servo

export ANDROID_SDK="/path/to/sdk"
export ANDROID_NDK="/path/to/ndk"
export ANDROID_TOOLCHAIN="/path/to/toolchain"
export PATH="$PATH:/path/to/toolchain/bin"

./mach build --release --android
./mach package --release --android

Rather than setting the ANDROID_* environment variables every time, you can also create a .servobuild file and then edit it to contain the correct paths to the Android SDK/NDK tools:

cp servobuild.example .servobuild
# edit .servobuild


Use ./mach run [url] to run Servo. Also, don't miss the info on the browserhtml page on how to run the Browser.html full tech demo (it provides a more browser-like experience than just browsing a single URL with servo).

Commandline Arguments

  • -p INTERVAL turns on the profiler and dumps info to the console every INTERVAL seconds
  • -s SIZE sets the tile size for painting; defaults to 512
  • -z disables all graphical output; useful for running JS / layout tests
  • -Z help displays useful output to debug servo

Keyboard Shortcuts

  • Ctrl+- zooms out
  • Ctrl+= zooms in
  • Alt+left arrow goes backwards in the history
  • Alt+right arrow goes forwards in the history
  • Esc exits servo


There are lots of mach commands you can use. You can list them with ./mach --help.

The generated documentation can be found on