diff --git a/.arcbuild b/.arcbuild
new file mode 100644
--- /dev/null
+++ b/.arcbuild
@@ -0,0 +1,3 @@
+{
+  "build_directory": "build-arcanist"
+}
diff --git a/arcanist/.phutil_module_cache b/arcanist/.phutil_module_cache
--- a/arcanist/.phutil_module_cache
+++ b/arcanist/.phutil_module_cache
@@ -1 +1 @@
-{"__symbol_cache_version__":11,"d60c8224f471e0ecddc2a6f3c6839cd1":{"have":{"class":{"AutoPEP8FormatLinter":75}},"need":{"function":{"pht":297,"id":1317},"class":{"ArcanistExternalLinter":104,"ArcanistLintMessage":1324,"Filesystem":1168,"ArcanistLinter":1431,"ArcanistLintSeverity":1509}},"xmap":{"AutoPEP8FormatLinter":["ArcanistExternalLinter"]}},"213c3145da34ed6dfc0d70d628a2a086":{"have":{"class":{"CheckDocLinter":106}},"need":{"function":{"pht":323,"id":1868},"class":{"ArcanistExternalLinter":129,"ArcanistLintMessage":1875,"Filesystem":737,"ArcanistLinter":1923,"ArcanistLintSeverity":2009}},"xmap":{"CheckDocLinter":["ArcanistExternalLinter"]}},"7bab1f879b8a86dd9977b8c0d075935f":{"have":{"class":{"ClangFormatLinter":79}},"need":{"function":{"pht":302,"execx":787,"id":1664},"class":{"ArcanistExternalLinter":105,"ArcanistLintMessage":1671,"Filesystem":1515,"ArcanistLinter":1778,"ArcanistLintSeverity":1856}},"xmap":{"ClangFormatLinter":["ArcanistExternalLinter"]}},"0e068a1116ed03e86a2388020a821983":{"have":{"class":{"PythonFormatLinter":75}},"need":{"function":{"pht":305,"id":1614},"class":{"ArcanistExternalLinter":102,"ArcanistLintMessage":1621,"Filesystem":733,"ArcanistLinter":1752,"ArcanistLintSeverity":1835}},"xmap":{"PythonFormatLinter":["ArcanistExternalLinter"]}},"ea2beb1668dfbdd87488f18fbb20178f":{"have":{"class":{"TestsLinter":103}},"need":{"function":{"pht":318,"id":2676},"class":{"ArcanistExternalLinter":123,"ArcanistLintMessage":2683,"Filesystem":791,"ArcanistLinter":2731,"ArcanistLintSeverity":2839}},"xmap":{"TestsLinter":["ArcanistExternalLinter"]}}}
\ No newline at end of file
+{"__symbol_cache_version__":11,"90a8b110dc475955f15bb81d37268cb5":{"have":{"class":{"AutoPEP8FormatLinter":75}},"need":{"function":{"pht":297,"execx":769,"id":1903},"class":{"ArcanistExternalLinter":104,"ArcanistLintMessage":1910,"Filesystem":1754,"ArcanistLinter":2017,"ArcanistLintSeverity":2095}},"xmap":{"AutoPEP8FormatLinter":["ArcanistExternalLinter"]}},"bf0805c02029a7226e8c0d7dee039b3c":{"have":{"class":{"CheckDocLinter":106}},"need":{"function":{"pht":323,"id":1847},"class":{"ArcanistExternalLinter":129,"ArcanistLintMessage":1854,"Filesystem":731,"ArcanistLinter":1902,"ArcanistLintSeverity":1988}},"xmap":{"CheckDocLinter":["ArcanistExternalLinter"]}},"6af7410cfea496ff1d4dcc2624b6b8ea":{"have":{"class":{"ClangFormatLinter":79}},"need":{"function":{"pht":302,"execx":781,"id":1653},"class":{"ArcanistExternalLinter":105,"ArcanistLintMessage":1660,"Filesystem":1504,"ArcanistLinter":1767,"ArcanistLintSeverity":1845}},"xmap":{"ClangFormatLinter":["ArcanistExternalLinter"]}},"6f2f22dd0f259fb2eaa284b4fab3bc29":{"have":{"class":{"PythonFormatLinter":123}},"need":{"function":{"pht":353,"id":1838},"class":{"ArcanistExternalLinter":150,"ArcanistLintMessage":1845,"Filesystem":776,"ArcanistLinter":1970,"ArcanistLintSeverity":2053}},"xmap":{"PythonFormatLinter":["ArcanistExternalLinter"]}},"25781df78f6eebfb223296b8265e9d19":{"have":{"class":{"TestsLinter":103}},"need":{"function":{"pht":318,"id":2629},"class":{"ArcanistExternalLinter":123,"ArcanistLintMessage":2636,"Filesystem":776,"ArcanistLinter":2684,"ArcanistLintSeverity":2792}},"xmap":{"TestsLinter":["ArcanistExternalLinter"]}},"e6113630a098d3a50f65500a5c577a98":{"have":{"class":{"ArcanistBuildWorkflow":48}},"need":{"function":{"phutil_console_format":342,"pht":958,"phutil_json_decode":3778},"class":{"ArcanistWorkflow":78,"ExecFuture":1433,"PhutilConsole":1016,"Filesystem":2165},"class\/interface":{"FilesystemException":2435,"PhutilJSONParserException":3824}},"xmap":{"ArcanistBuildWorkflow":["ArcanistWorkflow"]}}}
\ No newline at end of file
diff --git a/arcanist/__phutil_library_map__.php b/arcanist/__phutil_library_map__.php
--- a/arcanist/__phutil_library_map__.php
+++ b/arcanist/__phutil_library_map__.php
@@ -9,6 +9,7 @@
 phutil_register_library_map(array(
   '__library_version__' => 2,
   'class' => array(
+    'ArcanistBuildWorkflow' => 'workflow/ArcanistBuildWorkflow.php',
     'AutoPEP8FormatLinter' => 'linter/AutoPEP8Linter.php',
     'CheckDocLinter' => 'linter/CheckDocLinter.php',
     'ClangFormatLinter' => 'linter/ClangFormatLinter.php',
@@ -17,6 +18,7 @@
   ),
   'function' => array(),
   'xmap' => array(
+    'ArcanistBuildWorkflow' => 'ArcanistWorkflow',
     'AutoPEP8FormatLinter' => 'ArcanistExternalLinter',
     'CheckDocLinter' => 'ArcanistExternalLinter',
     'ClangFormatLinter' => 'ArcanistExternalLinter',
diff --git a/arcanist/workflow/ArcanistBuildWorkflow.php b/arcanist/workflow/ArcanistBuildWorkflow.php
new file mode 100644
--- /dev/null
+++ b/arcanist/workflow/ArcanistBuildWorkflow.php
@@ -0,0 +1,205 @@
+<?php
+
+/**
+ * Build the project
+ */
+final class ArcanistBuildWorkflow extends ArcanistWorkflow {
+
+  const RESULT_OKAY = 0;
+  const RESULT_WARNINGS = 1;
+  const RESULT_ERRORS = 2;
+  const RESULT_SKIP = 3;
+
+  private $buildDir;
+
+  public function getWorkflowName() {
+    return 'build';
+  }
+
+  public function getCommandSynopses() {
+    return phutil_console_format(<<<EOTEXT
+      **build** [__targets__]
+EOTEXT
+    );
+  }
+
+  public function getCommandHelp() {
+    return phutil_console_format(<<<EOTEXT
+      Build the bitcoin-abc project using CMake and Ninja.
+      You can specify the Ninja targets by passing them to __targets__.
+      Requires: cmake, ninja
+EOTEXT
+    );
+  }
+
+  public function getArguments() {
+    return array(
+      '*' => 'targets',
+    );
+  }
+
+  public function requiresWorkingCopy() {
+    return true;
+  }
+
+  private function setSuccess($duration) {
+    $out = phutil_console_format("**<bg:green> %s </bg>** %s (%.3f s)\n",
+      pht('OKAY'), pht('Build is successful'), $duration);
+
+    PhutilConsole::getConsole()->writeOut($out);
+
+    return self::RESULT_OKAY;
+  }
+
+  private function setFailure($failureReason) {
+    $out = phutil_console_format( "**<bg:red> %s </bg>** %s\n", pht('FAILED'),
+      pht($failureReason));
+
+    PhutilConsole::getConsole()->writeOut($out);
+
+    return self::RESULT_ERRORS;
+  }
+
+  private function build() {
+    /* Run CMake from the build repository */
+    $future = new ExecFuture(
+      'cmake -GNinja '.$this->getWorkingCopy()->getProjectRoot());
+    $future->setCWD($this->buildDir);
+    list($ret) = $future->resolve();
+
+    if ($ret != 0) {
+      return false;
+    }
+
+    /*
+     * Run Ninja from the build directory.
+     * If "targets" arguments are specified, pass them to Ninja, otherwise do
+     * not speficy any target and let Ninja build the default.
+     */
+    $targets = $this->getArgument('targets');
+    $cmd = 'ninja';
+    foreach ($targets as $_) {
+      $cmd .= ' %s';
+    }
+
+    $future = new ExecFuture($cmd, ...$targets);
+    $future->setCWD($this->buildDir);
+    list($ret) = $future->resolve();
+
+    return $ret == 0;
+  }
+
+  private function removeBuildDirectory() {
+    if (!Filesystem::pathExists($this->buildDir)) {
+      return true;
+    }
+
+    if (Filesystem::pathsAreEquivalent($this->buildDir,
+      $this->getWorkingCopy()->getProjectRoot())) {
+      return false;
+    }
+
+    try {
+      Filesystem::remove($this->buildDir);
+    } catch (FilesystemException $e) {
+      return false;
+    }
+
+    return true;
+  }
+
+  public function run() {
+    if (!Filesystem::binaryExists('cmake')) {
+      return $this->setFailure(
+        'The `cmake` command is required to run `arc build`. Please install '.
+        'CMake (https://cmake.org) then run `arc build` again.');
+    }
+
+    if (!Filesystem::binaryExists('ninja')) {
+      return $this->setFailure(
+        'The `ninja` command is required to run `arc build`. Please install '.
+        'Ninja (https://ninja-build.org) hen run `arc build` again.');
+    }
+
+    $workingCopy = $this->getWorkingCopy();
+
+    /*
+     * Create the build directory if it doesn't exist.
+     * The build directory is read from the option
+     * `build_directory` in the `.arcbuild` configuration file.
+     *
+     * If the directory already exists, remove it first.
+     */
+
+    /* Find the .arcbuild configuration file. */
+    $configPath = $workingCopy->getProjectPath('.arcbuild');
+    if (!Filesystem::pathExists($configPath)) {
+      return $this->setFailure(
+        'Unable to find the `.arcbuild` configuration file. Please create the '.
+        'file at the root of the project.');
+    }
+
+    /* Read the .arcbuild configuration file, check it is a valid json file. */
+    $configData = Filesystem::readFile($configPath);
+    try {
+      $config = phutil_json_decode($configData);
+    } catch (PhutilJSONParserException $e) {
+      return $this->setFailure(
+        'The `.arcbuild` file is not a valid JSON file, please check for '.
+        'syntax errors.');
+    }
+
+    /* Make sure the `build_directory` option is set. */
+    if (!array_key_exists('build_directory', $config)) {
+      return $this->setFailure(
+        'No build directory is configured. Set the `build_directory` option '.
+        'in your `.arcbuild` configuration file and run `arc build` again.');
+    }
+
+    $root = $workingCopy->getProjectRoot();
+    $this->buildDir = Filesystem::resolvePath($config['build_directory'],
+      $root);
+
+    /* Disallow to set the project root as the build directory. */
+    if (Filesystem::pathsAreEquivalent($this->buildDir, $root)) {
+      return $this->setFailure(
+        'The build directory is set to the project root: '.$this->buildDir.'. '.
+        'The directory is removed after the build, please set it to something '.
+        'else.');
+    }
+
+    /* If the build directory exists, try to remove it first. */
+    if (!$this->removeBuildDirectory()) {
+      return $this->setFailure(
+        'The build directory '.$this->buildDir.' already exists and cannot be '.
+        'deleted. Please check the permissions or delete it manually then '.
+        'run `arc build` again.');
+    }
+
+    /* Create the build directory. */
+    try {
+      $this->buildDir = Filesystem::createDirectory($this->buildDir, 0755,
+        true);
+    } catch (FilesystemException $e) {
+      return $this->setFailure(
+        'Unable to create the build directory: '.$this->buildDir.'. Check you '.
+        'have write permissions to the parent directory and run `arc build` '.
+        'again.');
+    }
+
+    /* Build the project, and measure the build duration. */
+    $timeStart = microtime(true);
+
+    if (!$this->build()) {
+      return $this->setFailure('Build failed !');
+    }
+
+    $timeEnd = microtime(true);
+
+    return $this->setSuccess($timeEnd - $timeStart);
+  }
+
+  public function finalize() {
+    $this->removeBuildDirectory();
+  }
+}