diff --git a/playwright/__init__.py b/playwright/__init__.py
index 1ae7a7a9b..7db2a1221 100644
--- a/playwright/__init__.py
+++ b/playwright/__init__.py
@@ -20,6 +20,7 @@
 firefox = playwright_object.firefox
 webkit = playwright_object.webkit
 devices = playwright_object.devices
+selectors = playwright_object.selectors
 browser_types = playwright_object.browser_types
 Error = helper.Error
 TimeoutError = helper.TimeoutError
@@ -30,6 +31,7 @@
     "firefox",
     "webkit",
     "devices",
+    "selectors",
     "Error",
     "TimeoutError",
 ]
diff --git a/playwright/js_handle.py b/playwright/js_handle.py
index 7b38427ed..e8f2ded21 100644
--- a/playwright/js_handle.py
+++ b/playwright/js_handle.py
@@ -73,10 +73,10 @@ async def getProperty(self, name: str) -> "JSHandle":
         return from_channel(await self._channel.send("getProperty", dict(name=name)))
 
     async def getProperties(self) -> Dict[str, "JSHandle"]:
-        map = dict()
-        for property in await self._channel.send("getPropertyList"):
-            map[property["name"]] = from_channel(property["value"])
-        return map
+        return {
+            prop["name"]: from_channel(prop["value"])
+            for prop in await self._channel.send("getPropertyList")
+        }
 
     def asElement(self) -> Optional["ElementHandle"]:
         return None
diff --git a/playwright/object_factory.py b/playwright/object_factory.py
index a3d5a310b..e019d30a3 100644
--- a/playwright/object_factory.py
+++ b/playwright/object_factory.py
@@ -28,6 +28,7 @@
 from playwright.network import Request, Response, Route
 from playwright.page import BindingCall, Page
 from playwright.playwright import Playwright
+from playwright.selectors import Selectors
 from playwright.worker import Worker
 
 
@@ -73,4 +74,6 @@ def create_remote_object(
         return Route(scope, guid, initializer)
     if type == "worker":
         return Worker(scope, guid, initializer)
+    if type == "selectors":
+        return Selectors(scope, guid, initializer)
     return DummyObject(scope, guid, initializer)
diff --git a/playwright/playwright.py b/playwright/playwright.py
index 7239ab2ac..85aa6207f 100644
--- a/playwright/playwright.py
+++ b/playwright/playwright.py
@@ -16,6 +16,7 @@
 
 from playwright.browser_type import BrowserType
 from playwright.connection import ChannelOwner, ConnectionScope, from_channel
+from playwright.selectors import Selectors
 
 
 class Playwright(ChannelOwner):
@@ -24,9 +25,11 @@ def __init__(self, scope: ConnectionScope, guid: str, initializer: Dict) -> None
         self.chromium: BrowserType = from_channel(initializer["chromium"])
         self.firefox: BrowserType = from_channel(initializer["firefox"])
         self.webkit: BrowserType = from_channel(initializer["webkit"])
-        self.devices = dict()
-        for device in initializer["deviceDescriptors"]:
-            self.devices[device["name"]] = device["descriptor"]
+        self.selectors: Selectors = from_channel(initializer["selectors"])
+        self.devices = {
+            device["name"]: device["descriptor"]
+            for device in initializer["deviceDescriptors"]
+        }
         self.browser_types: Dict[str, BrowserType] = dict(
             chromium=self.chromium, webkit=self.webkit, firefox=self.firefox
         )
diff --git a/playwright/selectors.py b/playwright/selectors.py
new file mode 100644
index 000000000..ee2f24cc8
--- /dev/null
+++ b/playwright/selectors.py
@@ -0,0 +1,39 @@
+# Copyright (c) Microsoft Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import Dict, Optional
+
+from playwright.connection import ChannelOwner, ConnectionScope
+from playwright.element_handle import ElementHandle
+
+
+class Selectors(ChannelOwner):
+    def __init__(self, scope: ConnectionScope, guid: str, initializer: Dict) -> None:
+        super().__init__(scope, guid, initializer)
+
+    async def register(
+        self, name: str, source: str = "", path: str = None, contentScript: bool = False
+    ) -> None:
+        if path:
+            with open(path, "r") as file:
+                source = file.read()
+        await self._channel.send(
+            "register",
+            dict(name=name, source=source, options={"contentScript": contentScript}),
+        )
+
+    async def _createSelector(self, name: str, handle: ElementHandle) -> Optional[str]:
+        return await self._channel.send(
+            "createSelector", dict(name=name, handle=handle._channel)
+        )
diff --git a/tests/assets/sectionselectorengine.js b/tests/assets/sectionselectorengine.js
new file mode 100644
index 000000000..e831d03ce
--- /dev/null
+++ b/tests/assets/sectionselectorengine.js
@@ -0,0 +1,10 @@
+({
+  create(root, target) {
+  },
+  query(root, selector) {
+    return root.querySelector('section');
+  },
+  queryAll(root, selector) {
+    return Array.from(root.querySelectorAll('section'));
+  }
+})
diff --git a/tests/conftest.py b/tests/conftest.py
index c49014b20..7441acc39 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -42,6 +42,11 @@ def event_loop():
     loop.close()
 
 
+@pytest.fixture(scope="session")
+def selectors():
+    return playwright.selectors
+
+
 @pytest.fixture(scope="session")
 def browser_type(browser_name: str):
     return playwright.browser_types[browser_name]
diff --git a/tests/test_queryselector.py b/tests/test_queryselector.py
new file mode 100644
index 000000000..a3bfb6fb4
--- /dev/null
+++ b/tests/test_queryselector.py
@@ -0,0 +1,154 @@
+import os
+
+import pytest
+
+from playwright.helper import Error
+from playwright.page import Page
+
+
+async def test_selectors_register_should_work(selectors, page: Page, utils):
+    await utils.register_selector_engine(
+        selectors,
+        "tag",
+        """{
+      create(root, target) {
+        return target.nodeName;
+      },
+      query(root, selector) {
+        return root.querySelector(selector);
+      },
+      queryAll(root, selector) {
+        return Array.from(root.querySelectorAll(selector));
+      }
+    }""",
+    )
+    await page.setContent("<div><span></span></div><div></div>")
+    assert (
+        await selectors._createSelector("tag", await page.querySelector("div")) == "DIV"
+    )
+    assert await page.evalOnSelector("tag=DIV", "e => e.nodeName") == "DIV"
+    assert await page.evalOnSelector("tag=SPAN", "e => e.nodeName") == "SPAN"
+    assert await page.evalOnSelectorAll("tag=DIV", "es => es.length") == 2
+
+    # Selector names are case-sensitive.
+    with pytest.raises(Error) as exc:
+        await page.querySelector("tAG=DIV")
+    assert 'Unknown engine "tAG" while parsing selector tAG=DIV' in exc.value.message
+
+
+async def test_selectors_register_should_work_with_path(selectors, page: Page, utils):
+    await utils.register_selector_engine(
+        selectors,
+        "foo",
+        path=os.path.join(
+            os.path.dirname(os.path.abspath(__file__)),
+            "assets/sectionselectorengine.js",
+        ),
+    )
+    await page.setContent("<section></section>")
+    assert await page.evalOnSelector("foo=whatever", "e => e.nodeName") == "SECTION"
+
+
+async def test_selectors_register_should_work_in_main_and_isolated_world(
+    selectors, page: Page, utils
+):
+    dummy_selector_script = """{
+      create(root, target) { },
+      query(root, selector) {
+        return window.__answer;
+      },
+      queryAll(root, selector) {
+        return [document.body, document.documentElement, window.__answer];
+      }
+    }"""
+
+    await utils.register_selector_engine(selectors, "main", dummy_selector_script)
+    await utils.register_selector_engine(
+        selectors, "isolated", dummy_selector_script, contentScript=True
+    )
+    await page.setContent("<div><span><section></section></span></div>")
+    await page.evaluate('() => window.__answer = document.querySelector("span")')
+    # Works in main if asked.
+    assert await page.evalOnSelector("main=ignored", "e => e.nodeName") == "SPAN"
+    assert (
+        await page.evalOnSelector("css=div >> main=ignored", "e => e.nodeName")
+        == "SPAN"
+    )
+    assert await page.evalOnSelectorAll(
+        "main=ignored", "es => window.__answer !== undefined"
+    )
+    assert (
+        await page.evalOnSelectorAll("main=ignored", "es => es.filter(e => e).length")
+        == 3
+    )
+    # Works in isolated by default.
+    assert await page.querySelector("isolated=ignored") is None
+    assert await page.querySelector("css=div >> isolated=ignored") is None
+    # $$eval always works in main, to avoid adopting nodes one by one.
+    assert await page.evalOnSelectorAll(
+        "isolated=ignored", "es => window.__answer !== undefined"
+    )
+    assert (
+        await page.evalOnSelectorAll(
+            "isolated=ignored", "es => es.filter(e => e).length"
+        )
+        == 3
+    )
+    # At least one engine in main forces all to be in main.
+    assert (
+        await page.evalOnSelector("main=ignored >> isolated=ignored", "e => e.nodeName")
+        == "SPAN"
+    )
+    assert (
+        await page.evalOnSelector("isolated=ignored >> main=ignored", "e => e.nodeName")
+        == "SPAN"
+    )
+    # Can be chained to css.
+    assert (
+        await page.evalOnSelector("main=ignored >> css=section", "e => e.nodeName")
+        == "SECTION"
+    )
+
+
+async def test_selectors_register_should_handle_errors(selectors, page: Page, utils):
+    with pytest.raises(Error) as exc:
+        await page.querySelector("neverregister=ignored")
+    assert (
+        'Unknown engine "neverregister" while parsing selector neverregister=ignored'
+        in exc.value.message
+    )
+
+    dummy_selector_engine_script = """{
+      create(root, target) {
+        return target.nodeName;
+      },
+      query(root, selector) {
+        return root.querySelector('dummy');
+      },
+      queryAll(root, selector) {
+        return Array.from(root.querySelectorAll('dummy'));
+      }
+    }"""
+
+    with pytest.raises(Error) as exc:
+        await selectors.register("$", dummy_selector_engine_script)
+    assert (
+        "Selector engine name may only contain [a-zA-Z0-9_] characters"
+        == exc.value.message
+    )
+
+    # Selector names are case-sensitive.
+    await utils.register_selector_engine(
+        selectors, "dummy", dummy_selector_engine_script
+    )
+    await utils.register_selector_engine(
+        selectors, "duMMy", dummy_selector_engine_script
+    )
+
+    with pytest.raises(Error) as exc:
+        await selectors.register("dummy", dummy_selector_engine_script)
+    assert exc.value.message == '"dummy" selector engine has been already registered'
+
+    with pytest.raises(Error) as exc:
+        await selectors.register("css", dummy_selector_engine_script)
+    assert exc.value.message == '"css" is a predefined selector engine'
diff --git a/tests/utils.py b/tests/utils.py
index 453ea32f4..928a5acc1 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -17,8 +17,9 @@
 
 from playwright.element_handle import ElementHandle
 from playwright.frame import Frame
-from playwright.helper import Viewport
+from playwright.helper import Error, Viewport
 from playwright.page import Page
+from playwright.selectors import Selectors
 
 
 class Utils:
@@ -60,5 +61,14 @@ async def verify_viewport(self, page: Page, width: int, height: int):
         assert await page.evaluate("window.innerWidth") == width
         assert await page.evaluate("window.innerHeight") == height
 
+    async def register_selector_engine(
+        self, selectors: Selectors, *args, **kwargs
+    ) -> None:
+        try:
+            await selectors.register(*args, **kwargs)
+        except Error as exc:
+            if "has been already registered" not in exc.message:
+                raise exc
+
 
 utils = Utils()