diff --git a/docs/Makefile b/docs/Makefile
index c81892065..47a6af731 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -53,10 +53,14 @@ quartodoc_impl: $(PYBIN) ## Build qmd files for API docs
 	$(eval export IN_QUARTODOC=true)
 	. $(PYBIN)/activate \
 	  && quartodoc interlinks \
-	  && quartodoc build --config _quartodoc-core.yml --verbose \
+		&& echo "::group::quartodoc build core docs" \
+	  && SHINY_MODE="core" quartodoc build --config _quartodoc-core.yml --verbose \
 	  && mv objects.json _objects_core.json \
-	  && quartodoc build --config _quartodoc-express.yml --verbose \
-	  && mv objects.json _objects_express.json
+	  && echo "::endgroup::" \
+		&& echo "::group::quartodoc build express docs" \
+	  && SHINY_MODE="express" quartodoc build --config _quartodoc-express.yml --verbose \
+	  && mv objects.json _objects_express.json \
+	  && echo "::endgroup::"
 
 quartodoc_post: $(PYBIN)  ## Post-process qmd files for API docs
 	. $(PYBIN)/activate \
diff --git a/docs/_renderer_core.py b/docs/_renderer_core.py
index a46d51292..332a4ab93 100644
--- a/docs/_renderer_core.py
+++ b/docs/_renderer_core.py
@@ -2,6 +2,7 @@
 
 import base64
 import html
+import os
 import re
 from importlib.resources import files
 from pathlib import Path
@@ -270,6 +271,10 @@ def read_file(file: str | Path, root_dir: str | Path | None = None) -> FileConte
 
 
 def check_if_missing_expected_example(el, converted):
+    if os.environ.get("SHINY_MODE") == "express":
+        # These errors are thrown much earlier by @add_example()
+        return
+
     if re.search(r"(^|\n)#{2,6} Examples\n", converted):
         # Manually added examples are fine
         return
diff --git a/shiny/_docstring.py b/shiny/_docstring.py
index a45a4edce..8ecc13c08 100644
--- a/shiny/_docstring.py
+++ b/shiny/_docstring.py
@@ -2,7 +2,8 @@
 
 import os
 import sys
-from typing import TYPE_CHECKING, Any, Callable, Optional, TypeVar
+from functools import wraps
+from typing import TYPE_CHECKING, Any, Callable, Literal, Optional, TypeVar
 
 
 def find_api_examples_dir(start_dir: str) -> Optional[str]:
@@ -29,6 +30,25 @@ def no_example(func: F) -> F:
     return func
 
 
+def no_example_express(decorator: Callable[..., F]) -> F | Callable[..., F]:
+    """
+    Prevent ``@add_example()`` from throwing an error about missing Express examples.
+    """
+
+    @wraps(decorator)
+    def wrapper_decorator(*args: Any, **kwargs: Any) -> F:
+        try:
+            # Apply the potentially problematic decorator
+            return decorator(*args, **kwargs)
+        except ExpressExampleNotFoundException:
+            # If an error occurs, return the original function
+            if args and callable(args[0]):
+                return args[0]
+            raise
+
+    return wrapper_decorator
+
+
 # This class is used to mark docstrings when @add_example() is used, so that an error
 # will be thrown if @doc_format() is used afterward. This is to avoid an error when
 # the example contains curly braces -- the @doc_format() decorator will try to evaluate
@@ -50,7 +70,7 @@ def write_example(self, app_files: list[str]) -> str:
 
 
 def add_example(
-    app_file: str = "app.py",
+    app_file: Optional[str] = None,
     ex_dir: Optional[str] = None,
 ) -> Callable[[F], F]:
     """
@@ -60,6 +80,14 @@ def add_example(
     ``__name__`` matches the name of directory under a ``api-examples/`` directory in
     the current or any parent directory.
 
+    * Examples for the ``shiny`` package are in ``shiny/api-examples/``.
+    * Examples for the ``shiny.express`` subpackage are in ``shiny/express/api-examples/``.
+
+    Functions that can be used in Express or Core and whose canonical implementation is
+    in the ``shiny`` package should have examples in ``shiny/api-examples``. In this
+    case, the express variant should include an ``-express`` suffix and the core
+    variation can be named with a ``-core`` suffix or ``app.py``.
+
     Parameters
     ----------
     app_file:
@@ -88,25 +116,40 @@ def _(func: F) -> F:
             ex_dir_found = find_api_examples_dir(func_dir)
 
             if ex_dir_found is None:
-                raise ValueError(
+                raise FileNotFoundError(
                     f"No example directory found for {fn_name} in {func_dir} or its parent directories."
                 )
             example_dir = os.path.join(ex_dir_found, fn_name)
         else:
-            example_dir = os.path.join(func_dir, ex_dir)
+            example_dir = os.path.abspath(os.path.join(func_dir, ex_dir))
 
-        example_file = os.path.join(example_dir, app_file)
-        if not os.path.exists(example_file):
-            raise ValueError(
-                f"No example for {fn_name} found in '{os.path.abspath(example_dir)}'."
+            if not os.path.exists(example_dir):
+                raise FileNotFoundError(
+                    f"Example directory '{example_dir}' does not exist for {fn_name}."
+                )
+
+        app_file_name = app_file or "app.py"
+        try:
+            example_file = app_choose_core_or_express(
+                os.path.join(example_dir, app_file_name)
             )
+        except ExampleNotFoundException as e:
+            func_dir = get_decorated_source_directory(func).split("py-shiny/")[1]
+            if "__code__" in dir(func):
+                print(
+                    f"::warning file={func_dir},line={func.__code__.co_firstlineno}::{e}"
+                )
+            else:
+                print(f"::warning file={func_dir}::{e}")
+
+            return func
 
         other_files: list[str] = []
         for f in os.listdir(example_dir):
             abs_f = os.path.join(example_dir, f)
             is_support_file = (
                 os.path.isfile(abs_f)
-                and f != app_file
+                and f != app_file_name
                 and f != "app.py"
                 and not f.startswith("app-")
                 and not f.startswith("__")
@@ -150,6 +193,86 @@ def _(func: F) -> F:
     return _
 
 
+def is_express_app(app_path: str) -> bool:
+    # We can't use .shiny.express._is_express.is_express_app() here because that would
+    # create a circular import.
+    if not os.path.exists(app_path):
+        return False
+
+    with open(app_path) as f:
+        for line in f:
+            if "from shiny.express" in line:
+                return True
+            elif "import shiny.express" in line:
+                return True
+    return False
+
+
+class ExampleNotFoundException(FileNotFoundError):
+    def __init__(
+        self,
+        file_names: list[str] | str,
+        dir: str,
+        type: Optional[Literal["core", "express"]] = None,
+    ) -> None:
+        self.type = type or os.environ.get("SHINY_MODE") or "core"
+        self.file_names = [file_names] if isinstance(file_names, str) else file_names
+        self.dir = dir
+
+    def __str__(self):
+        if self.type in ("core", "express"):
+            # Capitalize first letter
+            type = "a Shiny Express" if self.type == "express" else "a Shiny Core"
+        else:
+            type = "an"
+
+        return (
+            f"Could not find {type} example file named "
+            + f"{' or '.join(self.file_names)} in {self.dir}."
+        )
+
+
+class ExpressExampleNotFoundException(ExampleNotFoundException):
+    def __init__(
+        self,
+        file_names: list[str] | str,
+        dir: str,
+    ) -> None:
+        super().__init__(file_names, dir, "express")
+
+
+def app_choose_core_or_express(app_path: Optional[str] = None) -> str:
+    app_path = app_path or "app.py"
+
+    if os.environ.get("SHINY_MODE") == "express":
+        if is_express_app(app_path):
+            return app_path
+
+        app_path = app_path.replace("-core.py", ".py")
+
+        path, ext = os.path.splitext(app_path)
+        app_path_express = f"{path}-express{ext}"
+
+        if not is_express_app(app_path_express):
+            raise ExpressExampleNotFoundException(
+                [os.path.basename(app_path), os.path.basename(app_path_express)],
+                os.path.dirname(app_path),
+            )
+
+        return app_path_express
+
+    if os.path.basename(app_path) == "app.py" and not os.path.exists(app_path):
+        app_path = app_path.replace("app.py", "app-core.py")
+
+    if not os.path.exists(app_path):
+        raise ExampleNotFoundException(
+            os.path.basename(app_path),
+            os.path.dirname(app_path),
+        )
+
+    return app_path
+
+
 def get_decorated_source_directory(func: FuncType) -> str:
     if hasattr(func, "__module__"):
         path = os.path.abspath(str(sys.modules[func.__module__].__file__))
diff --git a/shiny/api-examples/Module/app.py b/shiny/api-examples/Module/app-core.py
similarity index 100%
rename from shiny/api-examples/Module/app.py
rename to shiny/api-examples/Module/app-core.py
diff --git a/shiny/api-examples/Progress/app.py b/shiny/api-examples/Progress/app-core.py
similarity index 100%
rename from shiny/api-examples/Progress/app.py
rename to shiny/api-examples/Progress/app-core.py
diff --git a/shiny/api-examples/Progress/app-express.py b/shiny/api-examples/Progress/app-express.py
new file mode 100644
index 000000000..b4bde03f6
--- /dev/null
+++ b/shiny/api-examples/Progress/app-express.py
@@ -0,0 +1,21 @@
+import asyncio
+
+from shiny import reactive
+from shiny.express import input, render, ui
+
+ui.input_action_button("button", "Compute")
+
+
+@render.text
+@reactive.event(input.button)
+async def compute():
+    with ui.Progress(min=1, max=15) as p:
+        p.set(message="Calculation in progress", detail="This may take a while...")
+
+        for i in range(1, 15):
+            p.set(i, message="Computing")
+            await asyncio.sleep(0.1)
+            # Normally use time.sleep() instead, but it doesn't yet work in Pyodide.
+            # https://github.com/pyodide/pyodide/issues/2354
+
+    return "Done computing!"
diff --git a/shiny/api-examples/Renderer/app.py b/shiny/api-examples/Renderer/app-core.py
similarity index 100%
rename from shiny/api-examples/Renderer/app.py
rename to shiny/api-examples/Renderer/app-core.py
diff --git a/shiny/api-examples/SafeException/app.py b/shiny/api-examples/SafeException/app-core.py
similarity index 100%
rename from shiny/api-examples/SafeException/app.py
rename to shiny/api-examples/SafeException/app-core.py
diff --git a/shiny/api-examples/SilentCancelOutputException/app.py b/shiny/api-examples/SilentCancelOutputException/app-core.py
similarity index 100%
rename from shiny/api-examples/SilentCancelOutputException/app.py
rename to shiny/api-examples/SilentCancelOutputException/app-core.py
diff --git a/shiny/api-examples/SilentException/app.py b/shiny/api-examples/SilentException/app-core.py
similarity index 100%
rename from shiny/api-examples/SilentException/app.py
rename to shiny/api-examples/SilentException/app-core.py
diff --git a/shiny/api-examples/Value/app.py b/shiny/api-examples/Value/app-core.py
similarity index 72%
rename from shiny/api-examples/Value/app.py
rename to shiny/api-examples/Value/app-core.py
index fe0112954..04479492a 100644
--- a/shiny/api-examples/Value/app.py
+++ b/shiny/api-examples/Value/app-core.py
@@ -1,10 +1,10 @@
 from shiny import App, Inputs, Outputs, Session, reactive, render, ui
 
-app_ui = ui.page_fluid(
-    ui.input_action_button("minus", "-1"),
-    " ",
-    ui.input_action_button("plus", "+1"),
-    ui.br(),
+app_ui = ui.page_sidebar(
+    ui.sidebar(
+        ui.input_action_button("minus", "-1"),
+        ui.input_action_button("plus", "+1"),
+    ),
     ui.output_text("value"),
 )
 
@@ -12,13 +12,13 @@
 def server(input: Inputs, output: Outputs, session: Session):
     val = reactive.Value(0)
 
-    @reactive.Effect
+    @reactive.effect
     @reactive.event(input.minus)
     def _():
         newVal = val.get() - 1
         val.set(newVal)
 
-    @reactive.Effect
+    @reactive.effect
     @reactive.event(input.plus)
     def _():
         newVal = val.get() + 1
diff --git a/shiny/api-examples/Value/app-express.py b/shiny/api-examples/Value/app-express.py
new file mode 100644
index 000000000..80a55e165
--- /dev/null
+++ b/shiny/api-examples/Value/app-express.py
@@ -0,0 +1,28 @@
+from shiny import reactive
+from shiny.express import input, render, ui
+
+val = reactive.Value(0)
+
+
+@reactive.effect
+@reactive.event(input.minus)
+def _():
+    newVal = val.get() - 1
+    val.set(newVal)
+
+
+@reactive.effect
+@reactive.event(input.plus)
+def _():
+    newVal = val.get() + 1
+    val.set(newVal)
+
+
+with ui.sidebar():
+    ui.input_action_button("minus", "-1")
+    ui.input_action_button("plus", "+1")
+
+
+@render.text
+def value():
+    return str(val.get())
diff --git a/shiny/api-examples/accordion/app.py b/shiny/api-examples/accordion/app-core.py
similarity index 100%
rename from shiny/api-examples/accordion/app.py
rename to shiny/api-examples/accordion/app-core.py
diff --git a/shiny/api-examples/accordion_panel/app.py b/shiny/api-examples/accordion_panel/app-core.py
similarity index 100%
rename from shiny/api-examples/accordion_panel/app.py
rename to shiny/api-examples/accordion_panel/app-core.py
diff --git a/shiny/api-examples/as_fill_item/app.py b/shiny/api-examples/as_fill_item/app-core.py
similarity index 100%
rename from shiny/api-examples/as_fill_item/app.py
rename to shiny/api-examples/as_fill_item/app-core.py
diff --git a/shiny/api-examples/as_fillable_container/app.py b/shiny/api-examples/as_fillable_container/app-core.py
similarity index 100%
rename from shiny/api-examples/as_fillable_container/app.py
rename to shiny/api-examples/as_fillable_container/app-core.py
diff --git a/shiny/api-examples/calc/app.py b/shiny/api-examples/calc/app-core.py
similarity index 64%
rename from shiny/api-examples/calc/app.py
rename to shiny/api-examples/calc/app-core.py
index 603313593..fe2620253 100644
--- a/shiny/api-examples/calc/app.py
+++ b/shiny/api-examples/calc/app-core.py
@@ -4,16 +4,18 @@
 from shiny import App, Inputs, Outputs, Session, reactive, render, ui
 
 app_ui = ui.page_fluid(
-    ui.input_action_button("first", "Invalidate first (slow) computation"),
-    " ",
-    ui.input_action_button("second", "Invalidate second (fast) computation"),
-    ui.br(),
-    ui.output_ui("result"),
+    ui.card(
+        ui.layout_columns(
+            ui.input_action_button("first", "Invalidate first (slow) computation"),
+            ui.input_action_button("second", "Invalidate second (fast) computation"),
+        ),
+        ui.output_text_verbatim("result"),
+    )
 )
 
 
 def server(input: Inputs, output: Outputs, session: Session):
-    @reactive.Calc
+    @reactive.calc
     def first():
         input.first()
         p = ui.Progress()
@@ -23,12 +25,12 @@ def first():
         p.close()
         return random.randint(1, 1000)
 
-    @reactive.Calc
+    @reactive.calc
     def second():
         input.second()
         return random.randint(1, 1000)
 
-    @render.ui
+    @render.text
     def result():
         return first() + second()
 
diff --git a/shiny/api-examples/calc/app-express.py b/shiny/api-examples/calc/app-express.py
new file mode 100644
index 000000000..2361cea80
--- /dev/null
+++ b/shiny/api-examples/calc/app-express.py
@@ -0,0 +1,32 @@
+import random
+import time
+
+from shiny import reactive
+from shiny.express import input, render, ui
+
+
+@reactive.calc
+def first():
+    input.first()
+    p = ui.Progress()
+    for i in range(30):
+        p.set(i / 30, message="Computing, please wait...")
+        time.sleep(0.1)
+    p.close()
+    return random.randint(1, 1000)
+
+
+@reactive.calc
+def second():
+    input.second()
+    return random.randint(1, 1000)
+
+
+with ui.card():
+    with ui.layout_columns():
+        ui.input_action_button("first", "Invalidate first (slow) computation")
+        ui.input_action_button("second", "Invalidate second (fast) computation")
+
+    @render.text
+    def result():
+        return first() + second()
diff --git a/shiny/api-examples/card/app.py b/shiny/api-examples/card/app-core.py
similarity index 100%
rename from shiny/api-examples/card/app.py
rename to shiny/api-examples/card/app-core.py
diff --git a/shiny/api-examples/card_body/app.py b/shiny/api-examples/card_body/app-core.py
similarity index 100%
rename from shiny/api-examples/card_body/app.py
rename to shiny/api-examples/card_body/app-core.py
diff --git a/shiny/api-examples/card_footer/app.py b/shiny/api-examples/card_footer/app-core.py
similarity index 100%
rename from shiny/api-examples/card_footer/app.py
rename to shiny/api-examples/card_footer/app-core.py
diff --git a/shiny/api-examples/card_header/app.py b/shiny/api-examples/card_header/app-core.py
similarity index 100%
rename from shiny/api-examples/card_header/app.py
rename to shiny/api-examples/card_header/app-core.py
diff --git a/shiny/api-examples/close/app.py b/shiny/api-examples/close/app-core.py
similarity index 100%
rename from shiny/api-examples/close/app.py
rename to shiny/api-examples/close/app-core.py
diff --git a/shiny/api-examples/data_frame/app.py b/shiny/api-examples/data_frame/app-core.py
similarity index 100%
rename from shiny/api-examples/data_frame/app.py
rename to shiny/api-examples/data_frame/app-core.py
diff --git a/shiny/api-examples/download/app.py b/shiny/api-examples/download/app-core.py
similarity index 100%
rename from shiny/api-examples/download/app.py
rename to shiny/api-examples/download/app-core.py
diff --git a/shiny/api-examples/download_button/app.py b/shiny/api-examples/download_button/app-core.py
similarity index 100%
rename from shiny/api-examples/download_button/app.py
rename to shiny/api-examples/download_button/app-core.py
diff --git a/shiny/api-examples/download_link/app.py b/shiny/api-examples/download_link/app-core.py
similarity index 100%
rename from shiny/api-examples/download_link/app.py
rename to shiny/api-examples/download_link/app-core.py
diff --git a/shiny/api-examples/dynamic_route/app.py b/shiny/api-examples/dynamic_route/app-core.py
similarity index 100%
rename from shiny/api-examples/dynamic_route/app.py
rename to shiny/api-examples/dynamic_route/app-core.py
diff --git a/shiny/api-examples/effect/app.py b/shiny/api-examples/effect/app-core.py
similarity index 100%
rename from shiny/api-examples/effect/app.py
rename to shiny/api-examples/effect/app-core.py
diff --git a/shiny/api-examples/effect/app-express.py b/shiny/api-examples/effect/app-express.py
new file mode 100644
index 000000000..363ed50cd
--- /dev/null
+++ b/shiny/api-examples/effect/app-express.py
@@ -0,0 +1,15 @@
+from shiny import reactive
+from shiny.express import input, ui
+
+ui.input_action_button("show", "Show modal dialog")
+
+
+@reactive.effect
+@reactive.event(input.show)
+def show_important_message():
+    m = ui.modal(
+        "This is a somewhat important message.",
+        easy_close=True,
+        footer=None,
+    )
+    ui.modal_show(m)
diff --git a/shiny/api-examples/event/app.py b/shiny/api-examples/event/app-core.py
similarity index 100%
rename from shiny/api-examples/event/app.py
rename to shiny/api-examples/event/app-core.py
diff --git a/shiny/api-examples/extended_task/app.py b/shiny/api-examples/extended_task/app-core.py
similarity index 100%
rename from shiny/api-examples/extended_task/app.py
rename to shiny/api-examples/extended_task/app-core.py
diff --git a/shiny/api-examples/file_reader/app.py b/shiny/api-examples/file_reader/app-core.py
similarity index 100%
rename from shiny/api-examples/file_reader/app.py
rename to shiny/api-examples/file_reader/app-core.py
diff --git a/shiny/api-examples/include_css/app.py b/shiny/api-examples/include_css/app-core.py
similarity index 100%
rename from shiny/api-examples/include_css/app.py
rename to shiny/api-examples/include_css/app-core.py
diff --git a/shiny/api-examples/include_js/app.py b/shiny/api-examples/include_js/app-core.py
similarity index 100%
rename from shiny/api-examples/include_js/app.py
rename to shiny/api-examples/include_js/app-core.py
diff --git a/shiny/api-examples/input_action_button/app.py b/shiny/api-examples/input_action_button/app-core.py
similarity index 100%
rename from shiny/api-examples/input_action_button/app.py
rename to shiny/api-examples/input_action_button/app-core.py
diff --git a/shiny/api-examples/input_action_link/app.py b/shiny/api-examples/input_action_link/app-core.py
similarity index 100%
rename from shiny/api-examples/input_action_link/app.py
rename to shiny/api-examples/input_action_link/app-core.py
diff --git a/shiny/api-examples/input_action_link/app-express.py b/shiny/api-examples/input_action_link/app-express.py
new file mode 100644
index 000000000..39939d756
--- /dev/null
+++ b/shiny/api-examples/input_action_link/app-express.py
@@ -0,0 +1,20 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+from shiny import reactive
+from shiny.express import input, render, ui
+
+ui.input_slider("n", "Number of observations", min=0, max=1000, value=500)
+ui.input_action_link("go", "Go!")
+
+
+@render.plot(alt="A histogram")
+# reactive.event() to invalidate the plot when the button is pressed but not when
+# the slider is changed
+@reactive.event(input.go, ignore_none=False)
+def plot():
+    np.random.seed(19680801)
+    x = 100 + 15 * np.random.randn(input.n())
+    fig, ax = plt.subplots()
+    ax.hist(x, bins=30, density=True)
+    return fig
diff --git a/shiny/api-examples/input_checkbox/app.py b/shiny/api-examples/input_checkbox/app-core.py
similarity index 100%
rename from shiny/api-examples/input_checkbox/app.py
rename to shiny/api-examples/input_checkbox/app-core.py
diff --git a/shiny/api-examples/input_checkbox/app-express.py b/shiny/api-examples/input_checkbox/app-express.py
new file mode 100644
index 000000000..1c7e87f7e
--- /dev/null
+++ b/shiny/api-examples/input_checkbox/app-express.py
@@ -0,0 +1,8 @@
+from shiny.express import input, render, ui
+
+ui.input_checkbox("somevalue", "Some value", False)
+
+
+@render.ui
+def value():
+    return input.somevalue()
diff --git a/shiny/api-examples/input_checkbox_group/app.py b/shiny/api-examples/input_checkbox_group/app-core.py
similarity index 100%
rename from shiny/api-examples/input_checkbox_group/app.py
rename to shiny/api-examples/input_checkbox_group/app-core.py
diff --git a/shiny/api-examples/input_checkbox_group/app-express.py b/shiny/api-examples/input_checkbox_group/app-express.py
new file mode 100644
index 000000000..9f3b9652b
--- /dev/null
+++ b/shiny/api-examples/input_checkbox_group/app-express.py
@@ -0,0 +1,18 @@
+from shiny import req
+from shiny.express import input, render, ui
+
+ui.input_checkbox_group(
+    "colors",
+    "Choose color(s):",
+    {
+        "red": ui.span("Red", style="color: #FF0000;"),
+        "green": ui.span("Green", style="color: #00AA00;"),
+        "blue": ui.span("Blue", style="color: #0000AA;"),
+    },
+)
+
+
+@render.ui
+def val():
+    req(input.colors())
+    return "You chose " + ", ".join(input.colors())
diff --git a/shiny/api-examples/input_date/app.py b/shiny/api-examples/input_date/app-core.py
similarity index 100%
rename from shiny/api-examples/input_date/app.py
rename to shiny/api-examples/input_date/app-core.py
diff --git a/shiny/api-examples/input_date/app-express.py b/shiny/api-examples/input_date/app-express.py
new file mode 100644
index 000000000..bd696beb3
--- /dev/null
+++ b/shiny/api-examples/input_date/app-express.py
@@ -0,0 +1,24 @@
+from datetime import date
+
+from shiny.express import ui
+
+ui.input_date("date1", "Date:", value="2016-02-29")
+# Default value is the date in client's time zone
+ui.input_date("date2", "Date:")
+# value is always yyyy-mm-dd, even if the display format is different
+ui.input_date("date3", "Date:", value="2016-02-29", format="mm/dd/yy")
+# Pass in a Date object
+ui.input_date("date4", "Date:", value=date(2016, 2, 29))
+# Use different language and different first day of week
+ui.input_date("date5", "Date:", language="ru", weekstart=1)
+# Start with decade view instead of default month view
+ui.input_date("date6", "Date:", startview="decade")
+# Disable Mondays and Tuesdays.
+ui.input_date("date7", "Date:", daysofweekdisabled=[1, 2])
+# Disable specific dates.
+ui.input_date(
+    "date8",
+    "Date:",
+    value="2016-02-29",
+    datesdisabled=["2016-03-01", "2016-03-02"],
+)
diff --git a/shiny/api-examples/input_date_range/app.py b/shiny/api-examples/input_date_range/app-core.py
similarity index 100%
rename from shiny/api-examples/input_date_range/app.py
rename to shiny/api-examples/input_date_range/app-core.py
diff --git a/shiny/api-examples/input_date_range/app-express.py b/shiny/api-examples/input_date_range/app-express.py
new file mode 100644
index 000000000..66f79c5c4
--- /dev/null
+++ b/shiny/api-examples/input_date_range/app-express.py
@@ -0,0 +1,27 @@
+from datetime import date
+
+from shiny.express import ui
+
+ui.input_date_range("daterange1", "Date range:", start="2001-01-01", end="2010-12-31")
+# Default start and end is the current date in the client's time zone
+ui.input_date_range("daterange2", "Date range:")
+# start and end are always specified in yyyy-mm-dd, even if the display
+# format is different
+ui.input_date_range(
+    "daterange3",
+    "Date range:",
+    start="2001-01-01",
+    end="2010-12-31",
+    min="2001-01-01",
+    max="2012-12-21",
+    format="mm/dd/yy",
+    separator=" - ",
+)
+# Pass in Date objects
+ui.input_date_range(
+    "daterange4", "Date range:", start=date(2001, 1, 1), end=date(2010, 12, 31)
+)
+# Use different language and different first day of week
+ui.input_date_range("daterange5", "Date range:", language="de", weekstart=1)
+# Start with decade view instead of default month view
+ui.input_date_range("daterange6", "Date range:", startview="decade")
diff --git a/shiny/api-examples/input_file/app.py b/shiny/api-examples/input_file/app-core.py
similarity index 100%
rename from shiny/api-examples/input_file/app.py
rename to shiny/api-examples/input_file/app-core.py
diff --git a/shiny/api-examples/input_file/app-express.py b/shiny/api-examples/input_file/app-express.py
new file mode 100644
index 000000000..81222e4f7
--- /dev/null
+++ b/shiny/api-examples/input_file/app-express.py
@@ -0,0 +1,48 @@
+import pandas as pd
+
+from shiny import reactive
+from shiny.express import input, render, ui
+from shiny.types import FileInfo
+
+ui.input_file("file1", "Choose CSV File", accept=[".csv"], multiple=False)
+ui.input_checkbox_group(
+    "stats",
+    "Summary Stats",
+    choices=["Row Count", "Column Count", "Column Names"],
+    selected=["Row Count", "Column Count", "Column Names"],
+)
+
+
+@reactive.Calc
+def parsed_file():
+    file: list[FileInfo] | None = input.file1()
+    if file is None:
+        return pd.DataFrame()
+    return pd.read_csv(file[0]["datapath"])  # pyright: ignore[reportUnknownMemberType]
+
+
+@render.table
+def summary():
+    df = parsed_file()
+
+    if df.empty:
+        return pd.DataFrame()
+
+    # Get the row count, column count, and column names of the DataFrame
+    row_count = df.shape[0]
+    column_count = df.shape[1]
+    names = df.columns.tolist()
+    column_names = ", ".join(str(name) for name in names)
+
+    # Create a new DataFrame to display the information
+    info_df = pd.DataFrame(
+        {
+            "Row Count": [row_count],
+            "Column Count": [column_count],
+            "Column Names": [column_names],
+        }
+    )
+
+    # input.stats() is a list of strings; subset the columns based on the selected
+    # checkboxes
+    return info_df.loc[:, input.stats()]
diff --git a/shiny/api-examples/input_numeric/app.py b/shiny/api-examples/input_numeric/app-core.py
similarity index 100%
rename from shiny/api-examples/input_numeric/app.py
rename to shiny/api-examples/input_numeric/app-core.py
diff --git a/shiny/api-examples/input_numeric/app-express.py b/shiny/api-examples/input_numeric/app-express.py
new file mode 100644
index 000000000..7e06f1c0a
--- /dev/null
+++ b/shiny/api-examples/input_numeric/app-express.py
@@ -0,0 +1,8 @@
+from shiny.express import input, render, ui
+
+ui.input_numeric("obs", "Observations:", 10, min=1, max=100)
+
+
+@render.code
+def value():
+    return input.obs()
diff --git a/shiny/api-examples/input_password/app.py b/shiny/api-examples/input_password/app-core.py
similarity index 100%
rename from shiny/api-examples/input_password/app.py
rename to shiny/api-examples/input_password/app-core.py
diff --git a/shiny/api-examples/input_password/app-express.py b/shiny/api-examples/input_password/app-express.py
new file mode 100644
index 000000000..4366c5303
--- /dev/null
+++ b/shiny/api-examples/input_password/app-express.py
@@ -0,0 +1,11 @@
+from shiny import reactive
+from shiny.express import input, render, ui
+
+ui.input_password("password", "Password:")
+ui.input_action_button("go", "Go")
+
+
+@render.code
+@reactive.event(input.go)
+def value():
+    return input.password()
diff --git a/shiny/api-examples/input_radio_buttons/app.py b/shiny/api-examples/input_radio_buttons/app-core.py
similarity index 100%
rename from shiny/api-examples/input_radio_buttons/app.py
rename to shiny/api-examples/input_radio_buttons/app-core.py
diff --git a/shiny/api-examples/input_radio_buttons/app-express.py b/shiny/api-examples/input_radio_buttons/app-express.py
new file mode 100644
index 000000000..5354f4134
--- /dev/null
+++ b/shiny/api-examples/input_radio_buttons/app-express.py
@@ -0,0 +1,15 @@
+from shiny.express import input, render, ui
+
+ui.input_radio_buttons(
+    "rb",
+    "Choose one:",
+    {
+        "html": ui.HTML("<span style='color:red;'>Red Text</span>"),
+        "text": "Normal text",
+    },
+)
+
+
+@render.express
+def val():
+    "You chose " + input.rb()
diff --git a/shiny/api-examples/input_select/app.py b/shiny/api-examples/input_select/app-core.py
similarity index 100%
rename from shiny/api-examples/input_select/app.py
rename to shiny/api-examples/input_select/app-core.py
diff --git a/shiny/api-examples/input_select/app-express.py b/shiny/api-examples/input_select/app-express.py
new file mode 100644
index 000000000..c45482f0c
--- /dev/null
+++ b/shiny/api-examples/input_select/app-express.py
@@ -0,0 +1,16 @@
+from shiny.express import input, render, ui
+
+ui.input_select(
+    "state",
+    "Choose a state:",
+    {
+        "East Coast": {"NY": "New York", "NJ": "New Jersey", "CT": "Connecticut"},
+        "West Coast": {"WA": "Washington", "OR": "Oregon", "CA": "California"},
+        "Midwest": {"MN": "Minnesota", "WI": "Wisconsin", "IA": "Iowa"},
+    },
+)
+
+
+@render.text
+def value():
+    return "You choose: " + str(input.state())
diff --git a/shiny/api-examples/input_selectize/app.py b/shiny/api-examples/input_selectize/app-core.py
similarity index 97%
rename from shiny/api-examples/input_selectize/app.py
rename to shiny/api-examples/input_selectize/app-core.py
index bc2dd9bd9..23a63d376 100644
--- a/shiny/api-examples/input_selectize/app.py
+++ b/shiny/api-examples/input_selectize/app-core.py
@@ -17,7 +17,7 @@
     ),
     ui.output_text("value"),
     ui.input_selectize(
-        "state",
+        "state2",
         "Selectize Options",
         states,
         multiple=True,
@@ -32,7 +32,7 @@
         ),
     ),
     ui.input_selectize(
-        "state",
+        "state3",
         "Selectize plugins",
         states,
         multiple=True,
diff --git a/shiny/api-examples/input_selectize/app-express.py b/shiny/api-examples/input_selectize/app-express.py
new file mode 100644
index 000000000..d58e04154
--- /dev/null
+++ b/shiny/api-examples/input_selectize/app-express.py
@@ -0,0 +1,45 @@
+from html import escape  # noqa: F401
+
+from shiny.express import input, render, ui
+
+states = {
+    "East Coast": {"NY": "New York", "NJ": "New Jersey", "CT": "Connecticut"},
+    "West Coast": {"WA": "Washington", "OR": "Oregon", "CA": "California"},
+    "Midwest": {"MN": "Minnesota", "WI": "Wisconsin", "IA": "Iowa"},
+}
+
+ui.input_selectize(
+    "state",
+    "Choose a state:",
+    states,
+    multiple=True,
+)
+
+
+@render.text
+def value():
+    return "You choose: " + str(input.state())
+
+
+ui.input_selectize(
+    "state2",
+    "Selectize Options",
+    states,
+    multiple=True,
+    options=(
+        {
+            "placeholder": "Enter text",
+            "render": ui.js_eval(
+                '{option: function(item, escape) {return "<div><strong>Select " + escape(item.label) + "</strong></div>";}}'
+            ),
+            "create": True,
+        }
+    ),
+)
+ui.input_selectize(
+    "state3",
+    "Selectize plugins",
+    states,
+    multiple=True,
+    options={"plugins": ["clear_button"]},
+)
diff --git a/shiny/api-examples/input_slider/app.py b/shiny/api-examples/input_slider/app-core.py
similarity index 100%
rename from shiny/api-examples/input_slider/app.py
rename to shiny/api-examples/input_slider/app-core.py
diff --git a/shiny/api-examples/input_slider/app-express.py b/shiny/api-examples/input_slider/app-express.py
new file mode 100644
index 000000000..e6e701594
--- /dev/null
+++ b/shiny/api-examples/input_slider/app-express.py
@@ -0,0 +1,16 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+from shiny.express import input, render, ui
+
+ui.input_slider("obs", "Number of bins:", min=10, max=100, value=30)
+
+
+@render.plot
+def distPlot():
+    np.random.seed(19680801)
+    x = 100 + 15 * np.random.randn(437)
+
+    fig, ax = plt.subplots()
+    ax.hist(x, input.obs(), density=True)
+    return fig
diff --git a/shiny/api-examples/input_switch/app.py b/shiny/api-examples/input_switch/app-core.py
similarity index 86%
rename from shiny/api-examples/input_switch/app.py
rename to shiny/api-examples/input_switch/app-core.py
index a438d8195..f05cba431 100644
--- a/shiny/api-examples/input_switch/app.py
+++ b/shiny/api-examples/input_switch/app-core.py
@@ -2,12 +2,12 @@
 
 app_ui = ui.page_fluid(
     ui.input_switch("somevalue", "Some value", False),
-    ui.output_ui("value"),
+    ui.output_text("value"),
 )
 
 
 def server(input: Inputs, output: Outputs, session: Session):
-    @render.ui
+    @render.text
     def value():
         return input.somevalue()
 
diff --git a/shiny/api-examples/input_switch/app-express.py b/shiny/api-examples/input_switch/app-express.py
new file mode 100644
index 000000000..efd623850
--- /dev/null
+++ b/shiny/api-examples/input_switch/app-express.py
@@ -0,0 +1,8 @@
+from shiny.express import input, render, ui
+
+ui.input_switch("somevalue", "Some value", False)
+
+
+@render.text
+def value():
+    return input.somevalue()
diff --git a/shiny/api-examples/input_text/app.py b/shiny/api-examples/input_text/app-core.py
similarity index 100%
rename from shiny/api-examples/input_text/app.py
rename to shiny/api-examples/input_text/app-core.py
diff --git a/shiny/api-examples/input_text/app-express.py b/shiny/api-examples/input_text/app-express.py
new file mode 100644
index 000000000..8c0c30d69
--- /dev/null
+++ b/shiny/api-examples/input_text/app-express.py
@@ -0,0 +1,8 @@
+from shiny.express import input, render, ui
+
+ui.input_text("caption", "Caption:", "Data summary")
+
+
+@render.code
+def value():
+    return input.caption()
diff --git a/shiny/api-examples/input_text_area/app.py b/shiny/api-examples/input_text_area/app-core.py
similarity index 100%
rename from shiny/api-examples/input_text_area/app.py
rename to shiny/api-examples/input_text_area/app-core.py
diff --git a/shiny/api-examples/input_text_area/app-express.py b/shiny/api-examples/input_text_area/app-express.py
new file mode 100644
index 000000000..4841f56ee
--- /dev/null
+++ b/shiny/api-examples/input_text_area/app-express.py
@@ -0,0 +1,25 @@
+from shiny.express import input, render, ui
+
+ui.input_text_area(
+    "caption_regular",
+    "Caption:",
+    "Data summary\nwith\nmultiple\nlines",
+)
+
+
+@render.text
+def value_regular():
+    return input.caption_regular()
+
+
+ui.input_text_area(
+    "caption_autoresize",
+    ui.markdown("Caption (w/ `autoresize=True`):"),
+    "Data summary\nwith\nmultiple\nlines",
+    autoresize=True,
+)
+
+
+@render.text
+def value_autoresize():
+    return input.caption_autoresize()
diff --git a/shiny/api-examples/insert_accordion_panel/app.py b/shiny/api-examples/insert_accordion_panel/app-core.py
similarity index 100%
rename from shiny/api-examples/insert_accordion_panel/app.py
rename to shiny/api-examples/insert_accordion_panel/app-core.py
diff --git a/shiny/api-examples/insert_ui/app.py b/shiny/api-examples/insert_ui/app-core.py
similarity index 100%
rename from shiny/api-examples/insert_ui/app.py
rename to shiny/api-examples/insert_ui/app-core.py
diff --git a/shiny/api-examples/invalidate_later/app.py b/shiny/api-examples/invalidate_later/app-core.py
similarity index 60%
rename from shiny/api-examples/invalidate_later/app.py
rename to shiny/api-examples/invalidate_later/app-core.py
index 7966d01f0..66de8233d 100644
--- a/shiny/api-examples/invalidate_later/app.py
+++ b/shiny/api-examples/invalidate_later/app-core.py
@@ -2,16 +2,11 @@
 
 from shiny import App, Inputs, Outputs, Session, reactive, render, ui
 
-app_ui = ui.page_fluid(ui.output_ui("value"))
+app_ui = ui.page_fluid(ui.output_text("value"))
 
 
 def server(input: Inputs, output: Outputs, session: Session):
-    @reactive.Effect
-    def _():
-        reactive.invalidate_later(0.5)
-        print("Random int: ", random.randint(0, 10000))
-
-    @render.ui
+    @render.text
     def value():
         reactive.invalidate_later(0.5)
         return "Random int: " + str(random.randint(0, 10000))
diff --git a/shiny/api-examples/invalidate_later/app-express.py b/shiny/api-examples/invalidate_later/app-express.py
new file mode 100644
index 000000000..270c5e889
--- /dev/null
+++ b/shiny/api-examples/invalidate_later/app-express.py
@@ -0,0 +1,10 @@
+import random
+
+from shiny import reactive
+from shiny.express import render
+
+
+@render.text
+def value():
+    reactive.invalidate_later(0.5)
+    return "Random int: " + str(random.randint(0, 10000))
diff --git a/shiny/api-examples/isolate/app.py b/shiny/api-examples/isolate/app-core.py
similarity index 100%
rename from shiny/api-examples/isolate/app.py
rename to shiny/api-examples/isolate/app-core.py
diff --git a/shiny/api-examples/isolate/app-express.py b/shiny/api-examples/isolate/app-express.py
new file mode 100644
index 000000000..52f8b9c38
--- /dev/null
+++ b/shiny/api-examples/isolate/app-express.py
@@ -0,0 +1,23 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+from shiny import reactive
+from shiny.express import input, render, ui
+
+ui.input_slider("n", "Number of observations", min=0, max=1000, value=500)
+ui.input_action_button("go", "Go!", class_="btn-success")
+
+
+@render.plot(alt="A histogram")
+def plot():
+    # Take a reactive dependency on the action button...
+    input.go()
+
+    # ...but don't take a reactive dependency on the slider
+    with reactive.isolate():
+        np.random.seed(19680801)
+        x = 100 + 15 * np.random.randn(input.n())
+
+    fig, ax = plt.subplots()
+    ax.hist(x, bins=30, density=True)
+    return fig
diff --git a/shiny/api-examples/layout_column_wrap/app.py b/shiny/api-examples/layout_column_wrap/app-core.py
similarity index 100%
rename from shiny/api-examples/layout_column_wrap/app.py
rename to shiny/api-examples/layout_column_wrap/app-core.py
diff --git a/shiny/api-examples/layout_column_wrap/app-express.py b/shiny/api-examples/layout_column_wrap/app-express.py
new file mode 100644
index 000000000..0754d8b74
--- /dev/null
+++ b/shiny/api-examples/layout_column_wrap/app-express.py
@@ -0,0 +1,19 @@
+from shiny.express import ui
+
+with ui.hold() as a_card:
+    with ui.card():
+        "A simple card"
+
+# Always has 2 columns (on non-mobile)
+with ui.layout_column_wrap(width=1 / 2):
+    a_card
+    a_card
+    a_card
+
+ui.hr()
+
+# Has three columns when viewport is wider than 750px
+with ui.layout_column_wrap(width="250px"):
+    a_card
+    a_card
+    a_card
diff --git a/shiny/api-examples/layout_columns/app.py b/shiny/api-examples/layout_columns/app-core.py
similarity index 100%
rename from shiny/api-examples/layout_columns/app.py
rename to shiny/api-examples/layout_columns/app-core.py
diff --git a/shiny/api-examples/layout_columns/app-express.py b/shiny/api-examples/layout_columns/app-express.py
new file mode 100644
index 000000000..768056d5c
--- /dev/null
+++ b/shiny/api-examples/layout_columns/app-express.py
@@ -0,0 +1,38 @@
+from model_plots import (
+    plot_accuracy_over_time,
+    plot_feature_importance,
+    plot_loss_over_time,
+)
+
+from shiny.express import render, ui
+
+ui.page_opts(title="Model Dashboard")
+
+ui.markdown("Using `ui.layout_columns()` for the layout.")
+
+
+with ui.layout_columns(
+    col_widths={"sm": (5, 7, 12)},
+    # row_heights=(2, 3),
+    # height="700px",
+):
+    with ui.card(full_screen=True):
+        ui.card_header("Loss Over Time")
+
+        @render.plot
+        def loss_over_time():
+            return plot_loss_over_time()
+
+    with ui.card(full_screen=True):
+        ui.card_header("Accuracy Over Time")
+
+        @render.plot
+        def accuracy_over_time():
+            return plot_accuracy_over_time()
+
+    with ui.card(full_screen=True):
+        ui.card_header("Feature Importance")
+
+        @render.plot
+        def feature_importance():
+            return plot_feature_importance()
diff --git a/shiny/api-examples/layout_sidebar/app.py b/shiny/api-examples/layout_sidebar/app-core.py
similarity index 100%
rename from shiny/api-examples/layout_sidebar/app.py
rename to shiny/api-examples/layout_sidebar/app-core.py
diff --git a/shiny/api-examples/layout_sidebar/app-express.py b/shiny/api-examples/layout_sidebar/app-express.py
new file mode 100644
index 000000000..10482a396
--- /dev/null
+++ b/shiny/api-examples/layout_sidebar/app-express.py
@@ -0,0 +1,17 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+from shiny.express import input, render, ui
+
+with ui.layout_sidebar():
+    with ui.sidebar():
+        ui.input_slider("n", "N", min=0, max=100, value=20)
+
+    @render.plot(alt="A histogram")
+    def plot() -> object:
+        np.random.seed(19680801)
+        x = 100 + 15 * np.random.randn(437)
+
+        fig, ax = plt.subplots()
+        ax.hist(x, input.n(), density=True)
+        return fig
diff --git a/shiny/api-examples/markdown/app.py b/shiny/api-examples/markdown/app-core.py
similarity index 100%
rename from shiny/api-examples/markdown/app.py
rename to shiny/api-examples/markdown/app-core.py
diff --git a/shiny/api-examples/markdown/app-express.py b/shiny/api-examples/markdown/app-express.py
new file mode 100644
index 000000000..f1db29501
--- /dev/null
+++ b/shiny/api-examples/markdown/app-express.py
@@ -0,0 +1,13 @@
+from shiny.express import ui
+
+ui.markdown(
+    """
+    # Hello World
+
+    This is **markdown** and here is some `code`:
+
+    ```python
+    print('Hello world!')
+    ```
+    """
+)
diff --git a/shiny/api-examples/modal/app.py b/shiny/api-examples/modal/app-core.py
similarity index 100%
rename from shiny/api-examples/modal/app.py
rename to shiny/api-examples/modal/app-core.py
diff --git a/shiny/api-examples/nav_panel/app.py b/shiny/api-examples/nav_panel/app-core.py
similarity index 100%
rename from shiny/api-examples/nav_panel/app.py
rename to shiny/api-examples/nav_panel/app-core.py
diff --git a/shiny/api-examples/navset_hidden/app.py b/shiny/api-examples/navset_hidden/app-core.py
similarity index 100%
rename from shiny/api-examples/navset_hidden/app.py
rename to shiny/api-examples/navset_hidden/app-core.py
diff --git a/shiny/api-examples/notification_show/app.py b/shiny/api-examples/notification_show/app-core.py
similarity index 100%
rename from shiny/api-examples/notification_show/app.py
rename to shiny/api-examples/notification_show/app-core.py
diff --git a/shiny/api-examples/on_ended/app.py b/shiny/api-examples/on_ended/app-core.py
similarity index 100%
rename from shiny/api-examples/on_ended/app.py
rename to shiny/api-examples/on_ended/app-core.py
diff --git a/shiny/api-examples/on_flush/app.py b/shiny/api-examples/on_flush/app-core.py
similarity index 100%
rename from shiny/api-examples/on_flush/app.py
rename to shiny/api-examples/on_flush/app-core.py
diff --git a/shiny/api-examples/on_flushed/app.py b/shiny/api-examples/on_flushed/app-core.py
similarity index 100%
rename from shiny/api-examples/on_flushed/app.py
rename to shiny/api-examples/on_flushed/app-core.py
diff --git a/shiny/api-examples/output_image/app.py b/shiny/api-examples/output_image/app-core.py
similarity index 100%
rename from shiny/api-examples/output_image/app.py
rename to shiny/api-examples/output_image/app-core.py
diff --git a/shiny/api-examples/output_plot/app.py b/shiny/api-examples/output_plot/app-core.py
similarity index 100%
rename from shiny/api-examples/output_plot/app.py
rename to shiny/api-examples/output_plot/app-core.py
diff --git a/shiny/api-examples/output_table/app.py b/shiny/api-examples/output_table/app-core.py
similarity index 100%
rename from shiny/api-examples/output_table/app.py
rename to shiny/api-examples/output_table/app-core.py
diff --git a/shiny/api-examples/output_text/app.py b/shiny/api-examples/output_text/app-core.py
similarity index 100%
rename from shiny/api-examples/output_text/app.py
rename to shiny/api-examples/output_text/app-core.py
diff --git a/shiny/api-examples/output_transformer/app.py b/shiny/api-examples/output_transformer/app-core.py
similarity index 100%
rename from shiny/api-examples/output_transformer/app.py
rename to shiny/api-examples/output_transformer/app-core.py
diff --git a/shiny/api-examples/output_ui/app.py b/shiny/api-examples/output_ui/app-core.py
similarity index 100%
rename from shiny/api-examples/output_ui/app.py
rename to shiny/api-examples/output_ui/app-core.py
diff --git a/shiny/api-examples/page_fixed/app.py b/shiny/api-examples/page_fixed/app-core.py
similarity index 100%
rename from shiny/api-examples/page_fixed/app.py
rename to shiny/api-examples/page_fixed/app-core.py
diff --git a/shiny/api-examples/page_fluid/app.py b/shiny/api-examples/page_fluid/app-core.py
similarity index 100%
rename from shiny/api-examples/page_fluid/app.py
rename to shiny/api-examples/page_fluid/app-core.py
diff --git a/shiny/api-examples/page_sidebar/app.py b/shiny/api-examples/page_sidebar/app-core.py
similarity index 98%
rename from shiny/api-examples/page_sidebar/app.py
rename to shiny/api-examples/page_sidebar/app-core.py
index ba84c3fe8..8ce58f8b8 100644
--- a/shiny/api-examples/page_sidebar/app.py
+++ b/shiny/api-examples/page_sidebar/app-core.py
@@ -14,7 +14,6 @@
 
 
 def server(input: Inputs, output: Outputs, session: Session):
-    @output
     @render.plot(alt="A histogram")
     def plot() -> object:
         np.random.seed(19680801)
diff --git a/shiny/api-examples/page_sidebar/app-express.py b/shiny/api-examples/page_sidebar/app-express.py
new file mode 100644
index 000000000..4781f851c
--- /dev/null
+++ b/shiny/api-examples/page_sidebar/app-express.py
@@ -0,0 +1,17 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+from shiny.express import input, render, ui
+
+with ui.sidebar():
+    ui.input_slider("n", "N", min=0, max=100, value=20)
+
+
+@render.plot(alt="A histogram")
+def plot() -> object:
+    np.random.seed(19680801)
+    x = 100 + 15 * np.random.randn(437)
+
+    fig, ax = plt.subplots()
+    ax.hist(x, input.n(), density=True)
+    return fig
diff --git a/shiny/api-examples/panel_absolute/app.py b/shiny/api-examples/panel_absolute/app-core.py
similarity index 96%
rename from shiny/api-examples/panel_absolute/app.py
rename to shiny/api-examples/panel_absolute/app-core.py
index 10fab125e..3340e5f93 100644
--- a/shiny/api-examples/panel_absolute/app.py
+++ b/shiny/api-examples/panel_absolute/app-core.py
@@ -9,7 +9,7 @@
         draggable=True,
         width="300px",
         right="50px",
-        top="50%",
+        top="25%",
     ),
 )
 
diff --git a/shiny/api-examples/panel_absolute/app-express.py b/shiny/api-examples/panel_absolute/app-express.py
new file mode 100644
index 000000000..8cf254ecb
--- /dev/null
+++ b/shiny/api-examples/panel_absolute/app-express.py
@@ -0,0 +1,8 @@
+from shiny.express import ui
+
+ui.h2("A basic absolute panel example")
+
+with ui.panel_absolute(draggable=True, width="300px", right="50px", top="25%"):
+    with ui.panel_well():
+        "Drag me around!"
+        ui.input_slider("n", "N", min=0, max=100, value=20)
diff --git a/shiny/api-examples/panel_conditional/app.py b/shiny/api-examples/panel_conditional/app-core.py
similarity index 100%
rename from shiny/api-examples/panel_conditional/app.py
rename to shiny/api-examples/panel_conditional/app-core.py
diff --git a/shiny/api-examples/panel_conditional/app-express.py b/shiny/api-examples/panel_conditional/app-express.py
new file mode 100644
index 000000000..8f5fbb229
--- /dev/null
+++ b/shiny/api-examples/panel_conditional/app-express.py
@@ -0,0 +1,12 @@
+from shiny.express import ui
+
+ui.input_checkbox("show", "Show radio buttons", False)
+
+with ui.panel_conditional("input.show"):
+    ui.input_radio_buttons("radio", "Choose ", ["slider", "select"])
+
+with ui.panel_conditional("input.show && input.radio === 'slider'"):
+    ui.input_slider("slider", None, min=0, max=100, value=50)
+
+with ui.panel_conditional("input.show && input.radio === 'select'"):
+    ui.input_select("slider", None, ["A", "B", "C"])
diff --git a/shiny/api-examples/panel_title/app.py b/shiny/api-examples/panel_title/app-core.py
similarity index 100%
rename from shiny/api-examples/panel_title/app.py
rename to shiny/api-examples/panel_title/app-core.py
diff --git a/shiny/api-examples/poll/app.py b/shiny/api-examples/poll/app-core.py
similarity index 89%
rename from shiny/api-examples/poll/app.py
rename to shiny/api-examples/poll/app-core.py
index c9411d28a..f6ab621b6 100644
--- a/shiny/api-examples/poll/app.py
+++ b/shiny/api-examples/poll/app-core.py
@@ -89,9 +89,8 @@ def stock_quotes() -> pd.DataFrame:
 # === Define the Shiny UI and server ===============================
 
 app_ui = ui.page_fluid(
-    ui.row(
-        ui.column(
-            8,
+    ui.layout_columns(
+        ui.card(
             ui.markdown(
                 """
                 # `shiny.reactive.poll` demo
@@ -100,11 +99,14 @@ def stock_quotes() -> pd.DataFrame:
                 case, an in-memory sqlite3) with the help of `shiny.reactive.poll`.
                 """
             ),
-            class_="mb-3",
+            ui.input_selectize(
+                "symbols", "Filter by symbol", [""] + SYMBOLS, multiple=True
+            ),
+            ui.output_data_frame("table"),
+            fill=False,
         ),
-    ),
-    ui.input_selectize("symbols", "Filter by symbol", [""] + SYMBOLS, multiple=True),
-    ui.output_ui("table"),
+        col_widths=[8, 4],
+    )
 )
 
 
@@ -115,13 +117,9 @@ def filtered_quotes():
             df = df[df["symbol"].isin(input.symbols())]
         return df
 
-    @render.ui
+    @render.data_frame
     def table():
-        return ui.HTML(
-            filtered_quotes().to_html(
-                index=False, classes="table font-monospace w-auto"
-            )
-        )
+        return filtered_quotes()
 
 
 app = App(app_ui, server)
diff --git a/shiny/api-examples/popover/app.py b/shiny/api-examples/popover/app-core.py
similarity index 100%
rename from shiny/api-examples/popover/app.py
rename to shiny/api-examples/popover/app-core.py
diff --git a/shiny/api-examples/remove_accordion_panel/app.py b/shiny/api-examples/remove_accordion_panel/app-core.py
similarity index 100%
rename from shiny/api-examples/remove_accordion_panel/app.py
rename to shiny/api-examples/remove_accordion_panel/app-core.py
diff --git a/shiny/api-examples/remove_ui/app.py b/shiny/api-examples/remove_ui/app-core.py
similarity index 100%
rename from shiny/api-examples/remove_ui/app.py
rename to shiny/api-examples/remove_ui/app-core.py
diff --git a/shiny/api-examples/render_express/app.py b/shiny/api-examples/render_express/app-core.py
similarity index 100%
rename from shiny/api-examples/render_express/app.py
rename to shiny/api-examples/render_express/app-core.py
diff --git a/shiny/api-examples/render_image/app.py b/shiny/api-examples/render_image/app-core.py
similarity index 100%
rename from shiny/api-examples/render_image/app.py
rename to shiny/api-examples/render_image/app-core.py
diff --git a/shiny/api-examples/req/app.py b/shiny/api-examples/req/app-core.py
similarity index 100%
rename from shiny/api-examples/req/app.py
rename to shiny/api-examples/req/app-core.py
diff --git a/shiny/api-examples/row/app.py b/shiny/api-examples/row/app-core.py
similarity index 100%
rename from shiny/api-examples/row/app.py
rename to shiny/api-examples/row/app-core.py
diff --git a/shiny/api-examples/send_custom_message/app.py b/shiny/api-examples/send_custom_message/app-core.py
similarity index 100%
rename from shiny/api-examples/send_custom_message/app.py
rename to shiny/api-examples/send_custom_message/app-core.py
diff --git a/shiny/api-examples/showcase_bottom/app.py b/shiny/api-examples/showcase_bottom/app-core.py
similarity index 100%
rename from shiny/api-examples/showcase_bottom/app.py
rename to shiny/api-examples/showcase_bottom/app-core.py
diff --git a/shiny/api-examples/showcase_left_center/app.py b/shiny/api-examples/showcase_left_center/app-core.py
similarity index 100%
rename from shiny/api-examples/showcase_left_center/app.py
rename to shiny/api-examples/showcase_left_center/app-core.py
diff --git a/shiny/api-examples/showcase_top_right/app.py b/shiny/api-examples/showcase_top_right/app-core.py
similarity index 100%
rename from shiny/api-examples/showcase_top_right/app.py
rename to shiny/api-examples/showcase_top_right/app-core.py
diff --git a/shiny/api-examples/sidebar/app.py b/shiny/api-examples/sidebar/app-core.py
similarity index 100%
rename from shiny/api-examples/sidebar/app.py
rename to shiny/api-examples/sidebar/app-core.py
diff --git a/shiny/api-examples/sidebar/app-express.py b/shiny/api-examples/sidebar/app-express.py
new file mode 100644
index 000000000..17e80bb47
--- /dev/null
+++ b/shiny/api-examples/sidebar/app-express.py
@@ -0,0 +1,42 @@
+from shiny.express import input, render, ui
+
+ui.page_opts(fillable=True)
+
+with ui.card():
+    with ui.layout_sidebar():
+        with ui.sidebar(id="sidebar_left", open="desktop"):
+            "Left sidebar content"
+
+        @render.text
+        def state_left():
+            return f"input.sidebar_left(): {input.sidebar_left()}"
+
+
+with ui.card():
+    with ui.layout_sidebar():
+        with ui.sidebar(id="sidebar_right", position="right", open="desktop"):
+            "Right sidebar content"
+
+        @render.text
+        def state_right():
+            return f"input.sidebar_right(): {input.sidebar_right()}"
+
+
+with ui.card():
+    with ui.layout_sidebar():
+        with ui.sidebar(id="sidebar_closed", open="closed"):
+            "Closed sidebar content"
+
+        @render.text
+        def state_closed():
+            return f"input.sidebar_closed(): {input.sidebar_closed()}"
+
+
+with ui.card():
+    with ui.layout_sidebar():
+        with ui.sidebar(id="sidebar_always", open="always"):
+            "Always sidebar content"
+
+        @render.text
+        def state_always():
+            return f"input.sidebar_always(): {input.sidebar_always()}"
diff --git a/shiny/api-examples/template/app.py b/shiny/api-examples/template/app-core.py
similarity index 100%
rename from shiny/api-examples/template/app.py
rename to shiny/api-examples/template/app-core.py
diff --git a/shiny/api-examples/todo_list/app.py b/shiny/api-examples/todo_list/app-core.py
similarity index 100%
rename from shiny/api-examples/todo_list/app.py
rename to shiny/api-examples/todo_list/app-core.py
diff --git a/shiny/api-examples/tooltip/app.py b/shiny/api-examples/tooltip/app-core.py
similarity index 100%
rename from shiny/api-examples/tooltip/app.py
rename to shiny/api-examples/tooltip/app-core.py
diff --git a/shiny/api-examples/update_accordion/app.py b/shiny/api-examples/update_accordion/app-core.py
similarity index 100%
rename from shiny/api-examples/update_accordion/app.py
rename to shiny/api-examples/update_accordion/app-core.py
diff --git a/shiny/api-examples/update_accordion_panel/app.py b/shiny/api-examples/update_accordion_panel/app-core.py
similarity index 100%
rename from shiny/api-examples/update_accordion_panel/app.py
rename to shiny/api-examples/update_accordion_panel/app-core.py
diff --git a/shiny/api-examples/update_action_button/app.py b/shiny/api-examples/update_action_button/app-core.py
similarity index 100%
rename from shiny/api-examples/update_action_button/app.py
rename to shiny/api-examples/update_action_button/app-core.py
diff --git a/shiny/api-examples/update_checkbox/app.py b/shiny/api-examples/update_checkbox/app-core.py
similarity index 100%
rename from shiny/api-examples/update_checkbox/app.py
rename to shiny/api-examples/update_checkbox/app-core.py
diff --git a/shiny/api-examples/update_checkbox_group/app.py b/shiny/api-examples/update_checkbox_group/app-core.py
similarity index 100%
rename from shiny/api-examples/update_checkbox_group/app.py
rename to shiny/api-examples/update_checkbox_group/app-core.py
diff --git a/shiny/api-examples/update_date/app.py b/shiny/api-examples/update_date/app-core.py
similarity index 100%
rename from shiny/api-examples/update_date/app.py
rename to shiny/api-examples/update_date/app-core.py
diff --git a/shiny/api-examples/update_date_range/app.py b/shiny/api-examples/update_date_range/app-core.py
similarity index 100%
rename from shiny/api-examples/update_date_range/app.py
rename to shiny/api-examples/update_date_range/app-core.py
diff --git a/shiny/api-examples/update_navs/app.py b/shiny/api-examples/update_navs/app-core.py
similarity index 100%
rename from shiny/api-examples/update_navs/app.py
rename to shiny/api-examples/update_navs/app-core.py
diff --git a/shiny/api-examples/update_numeric/app.py b/shiny/api-examples/update_numeric/app-core.py
similarity index 100%
rename from shiny/api-examples/update_numeric/app.py
rename to shiny/api-examples/update_numeric/app-core.py
diff --git a/shiny/api-examples/update_popover/app.py b/shiny/api-examples/update_popover/app-core.py
similarity index 100%
rename from shiny/api-examples/update_popover/app.py
rename to shiny/api-examples/update_popover/app-core.py
diff --git a/shiny/api-examples/update_radio_buttons/app.py b/shiny/api-examples/update_radio_buttons/app-core.py
similarity index 100%
rename from shiny/api-examples/update_radio_buttons/app.py
rename to shiny/api-examples/update_radio_buttons/app-core.py
diff --git a/shiny/api-examples/update_select/app.py b/shiny/api-examples/update_select/app-core.py
similarity index 100%
rename from shiny/api-examples/update_select/app.py
rename to shiny/api-examples/update_select/app-core.py
diff --git a/shiny/api-examples/update_selectize/app.py b/shiny/api-examples/update_selectize/app-core.py
similarity index 100%
rename from shiny/api-examples/update_selectize/app.py
rename to shiny/api-examples/update_selectize/app-core.py
diff --git a/shiny/api-examples/update_sidebar/app.py b/shiny/api-examples/update_sidebar/app-core.py
similarity index 100%
rename from shiny/api-examples/update_sidebar/app.py
rename to shiny/api-examples/update_sidebar/app-core.py
diff --git a/shiny/api-examples/update_slider/app.py b/shiny/api-examples/update_slider/app-core.py
similarity index 100%
rename from shiny/api-examples/update_slider/app.py
rename to shiny/api-examples/update_slider/app-core.py
diff --git a/shiny/api-examples/update_text/app.py b/shiny/api-examples/update_text/app-core.py
similarity index 100%
rename from shiny/api-examples/update_text/app.py
rename to shiny/api-examples/update_text/app-core.py
diff --git a/shiny/api-examples/update_tooltip/app.py b/shiny/api-examples/update_tooltip/app-core.py
similarity index 100%
rename from shiny/api-examples/update_tooltip/app.py
rename to shiny/api-examples/update_tooltip/app-core.py
diff --git a/shiny/api-examples/value_box/app.py b/shiny/api-examples/value_box/app-core.py
similarity index 100%
rename from shiny/api-examples/value_box/app.py
rename to shiny/api-examples/value_box/app-core.py
diff --git a/shiny/api-examples/www_dir/app.py b/shiny/api-examples/www_dir/app-core.py
similarity index 100%
rename from shiny/api-examples/www_dir/app.py
rename to shiny/api-examples/www_dir/app-core.py
diff --git a/shiny/reactive/_core.py b/shiny/reactive/_core.py
index d7f0219c8..24c9de1ae 100644
--- a/shiny/reactive/_core.py
+++ b/shiny/reactive/_core.py
@@ -22,7 +22,7 @@
 
 from .. import _utils
 from .._datastructures import PriorityQueueFIFO
-from .._docstring import add_example, no_example
+from .._docstring import add_example, no_example, no_example_express
 from ..types import MISSING, MISSING_TYPE
 
 if TYPE_CHECKING:
@@ -199,7 +199,7 @@ def isolate(self) -> Generator[None, None, None]:
 _reactive_environment = ReactiveEnvironment()
 
 
-@add_example()
+@no_example_express(add_example())
 @contextlib.contextmanager
 def isolate() -> Generator[None, None, None]:
     """
diff --git a/shiny/types.py b/shiny/types.py
index e116e8454..963144412 100644
--- a/shiny/types.py
+++ b/shiny/types.py
@@ -16,7 +16,7 @@
 
 from htmltools import TagChild
 
-from ._docstring import add_example
+from ._docstring import add_example, no_example_express
 from ._typing_extensions import NotRequired, TypedDict
 
 if TYPE_CHECKING:
@@ -55,7 +55,7 @@ class FileInfo(TypedDict):
     """The path to the file on the server."""
 
 
-@add_example(ex_dir="./api-examples/output_image")
+@no_example_express(add_example(ex_dir="./api-examples/output_image"))
 class ImgData(TypedDict):
     """
     Return type for :class:`~shiny.render.image`.
@@ -79,7 +79,7 @@ class ImgData(TypedDict):
     """TODO """
 
 
-@add_example()
+@no_example_express(add_example())
 class SafeException(Exception):
     """
     Throw a safe exception.
@@ -93,7 +93,7 @@ class SafeException(Exception):
     pass
 
 
-@add_example()
+@no_example_express(add_example())
 class SilentException(Exception):
     """
     Throw a silent exception.
@@ -116,7 +116,7 @@ class SilentException(Exception):
     pass
 
 
-@add_example()
+@no_example_express(add_example())
 class SilentCancelOutputException(Exception):
     """
     Throw a silent exception and don't clear output