Step 1: Install the latest version of the MongoDB C driver.

The mongocxx driver builds on top of the MongoDB C driver.

  • For mongocxx-3.7.x, libmongoc 1.22.1 or later is required.
  • For mongocxx-3.6.x, libmongoc 1.17.0 or later is required.
  • For mongocxx-3.5.x, libmongoc 1.15.0 or later is required.
  • For mongocxx-3.4.x, libmongoc 1.13.0 or later is required.
  • For mongocxx-3.3.x, libmongoc 1.10.1 or later is required.
  • For mongocxx-3.2.x, libmongoc 1.9.2 or later is required.
  • For mongocxx-3.1.4+, libmongoc 1.7.0 or later is required.
  • For mongocxx-3.1.[0-3], libmongoc 1.5.0 or later is required.
  • For mongocxx-3.0.x, we recommend the last 1.4.x version of libmongoc

Unless you know that your package manager offers a high enough version, you will need to download and build from the source code. Get a tarball from the C Driver releases page.

Follow the instructions for building from a tarball at Installing libmongoc.

Industry best practices and some regulations require the use of TLS 1.1 or newer. The MongoDB C Driver supports TLS 1.1 on Linux if OpenSSL is at least version 1.0.1. On macOS and Windows, the C Driver uses native TLS implementations that support TLS 1.1.

Step 2: Choose a C++17 polyfill

The mongocxx driver uses the C++17 features std::optional and std::string_view. To compile the mongocxx driver for pre-C++17, you must choose one of the following implementations for these features:

MNMLSTC/core (default for non-Windows platforms) Select with -DBSONCXX_POLY_USE_MNMLSTC=1. NOTE: This option vendors a header-only installation of MNMLSTC/core into the bsoncxx library installation and will therefore download MLNMLSTC from GitHub during the build process. If you already have an available version of MNMLSTC on your system, you can avoid the download step by using -DBSONCXX_POLY_USE_SYSTEM_MNMLSTC.

Boost (default for Windows platforms) Select with -DBSONCXX_POLY_USE_BOOST=1. This is currently the only option if you are using a version of MSVC that does not support C++17.

std::experimental Select with -DBSONCXX_POLY_USE_STD_EXPERIMENTAL=1. If your toolchain’s standard library provides optional and string_view in the namespace std::experimental, you can use this option. Be aware that your standard library’s std::experimental implementation may change over time, breaking binary compatibility in unexpected ways. Note that this polyfill is not recommended and is unsupported.

Most users should be fine sticking with the default. However, if you have an existing application which makes heavy use of one of the available libraries, you may prefer to build the mongocxx driver against the same library.

DO NOT change your project’s polyfill if you need to create a stable binary interface.

Step 3: Download the latest version of the mongocxx driver.

The most reliable starting point for building the mongocxx driver is the latest release tarball.

The mongocxx releases page will have links to the release tarball for the version you wish you install. For example, to download version 3.7.0:

curl -OL
tar -xzf mongo-cxx-driver-r3.7.0.tar.gz
cd mongo-cxx-driver-r3.7.0/build

Make sure you change to the build directory of whatever source tree you obtain.

Step 4: Configure the driver

On Unix systems, libmongoc installs into /usr/local by default. Without additional configuration, mongocxx installs into its local build directory as a courtesy to those who build from source. To configure mongocxx for installation into /usr/local as well, use the following cmake command:

cmake ..                                \
    -DCMAKE_BUILD_TYPE=Release          \

If installing to a non-standard directory (i.e., one which the dynamic loader does not search), consider specifying the -DCMAKE_INSTALL_RPATH= option:

cmake ..                                \
    -DCMAKE_BUILD_TYPE=Release          \
    -DCMAKE_INSTALL_PREFIX=/opt/mongo   \

In the Unix examples that follow, mongocxx is customized in these ways:

  • libmongoc is found in /opt/mongo-c-driver.
  • mongocxx is to be installed into /opt/mongo-cxx-driver.

With those two distinct (arbitrary) install locations, a user would run this cmake command:

cmake ..                                            \
    -DCMAKE_BUILD_TYPE=Release                      \
    -DCMAKE_PREFIX_PATH=/opt/mongo-c-driver         \

Note If you need multiple paths in a CMake PATH variable, separate them with a semicolon like this: -DCMAKE_PREFIX_PATH="/your/cdriver/prefix;/some/other/path"

These options can be freely mixed with a C++17 polyfill option. For instance, this is how a user would run the command above with the Boost polyfill option:

cmake ..                                            \
    -DCMAKE_BUILD_TYPE=Release                      \
    -DBSONCXX_POLY_USE_BOOST=1                      \
    -DCMAKE_PREFIX_PATH=/opt/mongo-c-driver         \

Configuring with mongocxx 3.1.x or 3.0.x

Instead of the -DCMAKE_PREFIX_PATH option, users must specify the libmongoc installation directory by using the -DLIBMONGOC_DIR and -DLIBBSON_DIR options:

cmake ..                                            \
    -DCMAKE_BUILD_TYPE=Release                      \
    -DLIBMONGOC_DIR=/opt/mongo-c-driver             \
    -DLIBBSON_DIR=/opt/mongo-c-driver               \

Step 5: Build and install the driver

If you are using the default MNMLSTC polyfill and are installing to a directory requiring root permissions, you should install the polyfill with sudo before building the rest of mongocxx so you don’t have to run the entire build with sudo:

# Only for MNMLSTC polyfill
sudo cmake --build . --target EP_mnmlstc_core

Once MNMLSTC is installed, or if you are using a different polyfill, build and install the driver:

cmake --build .
sudo cmake --build . --target install

The driver can be uninstalled at a later time in one of two ways. First, the uninstall target can be called:

sudo cmake --build . --target uninstall

Second, the uninstall script can be called:

sudo /opt/mongo-cxx-driver/share/mongo-cxx-driver/