Mac Build Instructions

Google employee? See go/building-chrome-mac for extra tips.


  • A Mac running 10.9+.
  • Xcode 7.3+.
  • depot_tools.
  • The OSX 10.10 SDK. Run
    ls `xcode-select -p`/Platforms/MacOSX.platform/Developer/SDKs
    to check whether you have it. Building with the 10.11 SDK works too, but the releases currently use the 10.10 SDK.

Getting the code

Check out the source code using Git.

Before checking out, go to the waterfall and check that the source tree is open (to avoid pulling a broken tree).

The path to the build directory should not contain spaces (e.g. not ~/Mac OS X/chromium), as this will cause the build to fail. This includes your drive name, the default “Macintosh HD2” for a second drive has a space.


Chromium on OS X is built using the Ninja tool and the Clang compiler. See both of those pages for further details on how to tune the build.


gn gen out/gn

to generate build files (replace “gn” in “out/gn” with whatever you like), and then run

ninja -C out/gn chrome

to build. You can edit out/gn/ to configure the build.

Before you build, you may want to install API keys so that Chrome-integrated Google services work. This step is optional if you aren't testing those features.

Faster builds

Full rebuilds are about the same speed in Debug and Release, but linking is a lot faster in Release builds.


is_debug = false

in your to do a release build.


is_component_build = true

in your to build many small dylibs instead of a single large executable. This makes incremental builds much faster, at the cost of producing a binary that opens less quickly. Component builds work in both debug and release.


symbol_level = 1

in your to disable debug symbols altogether. This makes both full rebuilds and linking faster (at the cost of not getting symbolized backtraces in gdb).

You might also want to install ccache to speed up the build.


All build output is located in the out directory (in the example above, ~/chromium/src/out). You can find the applications at gn/Content and gn/

Unit Tests

We have several unit test targets that build, and tests that run and pass. A small subset of these is:

  • unit_tests from chrome/chrome.gyp
  • base_unittests from base/base.gyp
  • net_unittests from net/net.gyp
  • url_unittests from url/url.gyp

When these tests are built, you will find them in the out/gn directory. You can run them from the command line:



According to the Chromium style guide code is not allowed to have whitespace on the ends of lines.

Run git cl format after committing to your local branch and before uploading to clang-format your code.


Good debugging tips can be found here. If you would like to debug in a graphical environment, rather than using lldb at the command line, that is possible without building in Xcode. See Debugging in Xcode for information on how.


Once you’re comfortable with building Chromium, check out Contributing Code for information about writing code for Chromium and contributing it.

Using Xcode-Ninja Hybrid

While using Xcode is unsupported, gn supports a hybrid approach of using ninja for building, but Xcode for editing and driving compilation. Xcode is still slow, but it runs fairly well even with indexing enabled. Most people build in the Terminal and write code with a text editor though.

With hybrid builds, compilation is still handled by ninja, and can be run by the command line (e.g. ninja -C out/gn chrome) or by choosing the chrome target in the hybrid workspace and choosing build.

To use Xcode-Ninja Hybrid pass --ide=xcode to gn gen

gn gen out/gn --ide=xcode

Open it:

open out/gn/ninja/all.xcworkspace

You may run into a problem where http://YES is opened as a new tab every time you launch Chrome. To fix this, open the scheme editor for the Run scheme, choose the Options tab, and uncheck “Allow debugging when using document Versions Browser”. When this option is checked, Xcode adds --NSDocumentRevisionsDebugMode YES to the launch arguments, and the YES gets interpreted as a URL to open.

If you have problems building, join us in #chromium on and ask there. As mentioned above, be sure that the waterfall is green and the tree is open before checking out. This will increase your chances of success.

Improving performance of git status

git status is used frequently to determine the status of your checkout. Due to the number of files in Chromium‘s checkout, git status performance can be quite variable. Increasing the system’s vnode cache appears to help. By default, this command:

sysctl -a | egrep kern\..*vnodes

Outputs kern.maxvnodes: 263168 (263168 is 257 * 1024). To increase this setting:

sudo sysctl kern.maxvnodes=$((512*1024))

Higher values may be appropriate if you routinely move between different Chromium checkouts. This setting will reset on reboot, the startup setting can be set in /etc/sysctl.conf:

echo kern.maxvnodes=$((512*1024)) | sudo tee -a /etc/sysctl.conf

Or edit the file directly.

If your git --version reports 2.6 or higher, the following may also improve performance of git status:

git update-index --untracked-cache

Xcode license agreement

If you're getting the error

Agreeing to the Xcode/iOS license requires admin privileges, please re-run as root via sudo.

the Xcode license hasn't been accepted yet which (contrary to the message) any user can do by running:

xcodebuild -license

Only accepting for all users of the machine requires root:

sudo xcodebuild -license