diff --git a/buildbot/master/files/config/factories.py b/buildbot/master/files/config/factories.py
index f892afab..97d752a1 100644
--- a/buildbot/master/files/config/factories.py
+++ b/buildbot/master/files/config/factories.py
@@ -4,6 +4,7 @@
 from buildbot.plugins import steps, util
 from buildbot.process import buildstep
 from buildbot.status.results import SUCCESS
+from twisted.internet import defer
 import yaml
 
 import environments as envs
@@ -104,6 +105,104 @@ def make_step(self, command):
         return step_class(**step_kwargs)
 
 
+class StepsYAMLParsingStep(buildstep.ShellMixin, buildstep.BuildStep):
+    """
+    Step which resolves the in-tree YAML and dynamically adds test steps.
+    """
+
+    haltOnFailure = True
+    flunkOnFailure = True
+
+    def __init__(self, builder_name, environment, yaml_path, **kwargs):
+        kwargs = self.setupShellMixin(kwargs)
+        buildstep.BuildStep.__init__(self, **kwargs)
+        self.builder_name = builder_name
+        self.environment = environment
+        self.yaml_path = yaml_path
+
+    @defer.inlineCallbacks
+    def run(self):
+        try:
+            print_yaml_cmd = "cat {}".format(self.yaml_path)
+            cmd = yield self.makeRemoteShellCommand(
+                command=[print_yaml_cmd],
+                collectStdout=True
+            )
+            yield self.runCommand(cmd)
+
+            result = cmd.results()
+            if result != util.SUCCESS:
+                raise Exception("Command failed with return code: {}" .format(
+                    str(cmd.rc)
+                ))
+            else:
+                builder_steps = yaml.safe_load(cmd.stdout)
+                commands = builder_steps[self.builder_name]
+                dynamic_steps = [self.make_step(command)
+                                 for command in commands]
+        except Exception as e:  # Bad step configuration, fail build
+            # Capture the exception and re-raise with a friendly message
+            raise Exception("Bad step configuration for {}: {}".format(
+                self.builder_name,
+                str(e)
+            ))
+
+        # TODO: windows compatibility (use a custom script for this?)
+        pkill_step = steps.ShellCommand(command=["pkill", "-x", "servo"],
+                                        decodeRC={0: SUCCESS, 1: SUCCESS})
+        static_steps = [pkill_step]
+
+        self.build.steps += static_steps + dynamic_steps
+
+        defer.returnValue(result)
+
+    def make_step(self, command):
+        step_kwargs = {}
+        step_kwargs['env'] = self.environment
+
+        command = command.split(' ')
+        step_kwargs['command'] = command
+
+        step_class = steps.ShellCommand
+        args = iter(command)
+        for arg in args:
+            # Change Step class to capture warnings as needed
+            # (steps.Compile and steps.Test catch warnings)
+            if arg == './mach':
+                mach_arg = next(args)
+                if re.match('build(-.*)?', mach_arg):
+                    step_class = steps.Compile
+                elif re.match('test-.*', mach_arg):
+                    step_class = steps.Test
+
+            # Capture any logfiles
+            elif re.match('--log-.*', arg):
+                logfile = next(args)
+                if 'logfiles' not in step_kwargs:
+                    step_kwargs['logfiles'] = {}
+                step_kwargs['logfiles'][logfile] = logfile
+
+        return step_class(**step_kwargs)
+
+
+class DynamicServoYAMLFactory(ServoFactory):
+    """
+    Smart factory which takes a list of shell commands from a YAML file
+    located in the main servo/servo repository and creates the appropriate
+    Buildbot Steps.
+    Uses heuristics to infer Step type, if there are any logfiles, etc.
+    """
+
+    def __init__(self, builder_name, environment):
+
+        # util.BuildFactory is an old-style class so we cannot use super()
+        # but must hardcode the superclass here
+        ServoFactory.__init__(self, [
+            StepsYAMLParsingStep(builder_name, environment,
+                                 "etc/ci/buildbot_steps.yml")
+        ])
+
+
 doc = ServoFactory([
     # This is not dynamic because a) we need to pass the logEnviron kwarg
     # and b) changes to the documentation build are already encapsulated
diff --git a/buildbot/master/files/config/master.cfg b/buildbot/master/files/config/master.cfg
index f4b14ce9..da2b0436 100644
--- a/buildbot/master/files/config/master.cfg
+++ b/buildbot/master/files/config/master.cfg
@@ -65,6 +65,7 @@ c['schedulers'].append(schedulers.AnyBranchScheduler(
     builderNames=[
         "linux-dev",
         "linux-rel",
+        "linux-dev-yaml",
         "mac-rel-wpt",
         "mac-dev-unit",
         "mac-rel-css",
@@ -86,6 +87,7 @@ c['schedulers'].append(schedulers.ForceScheduler(
     builderNames=[
         "linux-dev",
         "linux-rel",
+        "linux-dev-yaml",
         "mac-rel-wpt",
         "mac-dev-unit",
         "mac-rel-css",
@@ -134,6 +136,23 @@ class DynamicServoBuilder(util.BuilderConfig):
         )
 
 
+class DynamicServoYAMLBuilder(util.BuilderConfig):
+    """
+    Builder which uses DynamicServoYAMLFactory to run steps from a
+    yaml file in the Servo source tree.
+    """
+    def __init__(self, name, slavenames, environment):
+        # util.BuilderConfig is an old-style class so we cannot use super()
+        # but must hardcode the superclass here
+        util.BuilderConfig.__init__(
+            self,
+            name=name,
+            slavenames=slavenames,
+            factory=factories.DynamicServoYAMLFactory(name, environment),
+            nextBuild=branch_priority,
+            category="auto",
+        )
+
 c['builders'] = [
     DynamicServoBuilder("linux-dev", LINUX_SLAVES, envs.build_linux),
     DynamicServoBuilder("linux-rel", LINUX_SLAVES, envs.build_linux),
@@ -158,6 +177,9 @@ c['builders'] = [
         factory=factories.doc,
         category="auto",
     ),
+    # Testing the In Tree YAML build
+    DynamicServoYAMLBuilder("linux-dev-yaml", LINUX_SLAVES,
+                            envs.build_linux)
 ]