diff --git a/pyproject.toml b/pyproject.toml
index 380a1ea..9fab6b9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -36,7 +36,7 @@ test = ["pytest", "pytest-cov", "django", "streamlit", "copier", "jinja2-time",
     "maturin", "uv", "briefcase", "textual"]
 qt = ["pyqt>5,<6", "pyqtwebengin>5,<6"]
 textual = ["textual>=0.80"]
-ipywidget = ["anywidget>=0.9", "ipywidgets>=8", "ipython"]
+ipywidget = ["anywidget>=0.9"]
 
 [project.scripts]
 projspec = "projspec.__main__:main"
diff --git a/src/projspec/library.py b/src/projspec/library.py
index 0b3f313..f248d56 100644
--- a/src/projspec/library.py
+++ b/src/projspec/library.py
@@ -101,10 +101,10 @@ def filter(self, filters: list[tuple[str, str]]) -> dict[str, Project]:
         return {k: v for k, v in self.entries.items() if _match(v, filters)}
 
     # ------------------------------------------------------------------
-    #  Rich display / ipywidget
+    #  Rich display / widget
     # ------------------------------------------------------------------
-    def ipywidget(self):
-        """Return an interactive Jupyter widget for this library.
+    def widget(self):
+        """Return an interactive widget for this library.
 
         The widget mirrors the two-pane UI used by the VSCode extension,
         the Qt app and the PyCharm plugin: a filterable project list on
@@ -113,8 +113,13 @@ def ipywidget(self):
         actions (rescan, create spec, remove from library, …) and per-
         artifact Make buttons.
 
-        Requires the optional ``anywidget`` and ``ipywidgets`` packages;
-        install them via ``pip install projspec[ipywidget]``.
+        Built on :mod:`anywidget` — no :mod:`ipywidgets` dependency is
+        required, so the widget runs under marimo as well as classic
+        Jupyter / JupyterLab.  Install via ``pip install projspec[ipywidget]``.
+
+        In marimo, return the widget from a cell to display it.  In
+        Jupyter, you can also just evaluate a :class:`ProjectLibrary`
+        directly (``_ipython_display_`` is called automatically).
 
         Only a single widget per notebook is supported - see the
         :mod:`projspec.webui.ipywidget` module docstring.
@@ -123,21 +128,30 @@ def ipywidget(self):
 
         return make_widget(self)
 
+    def ipywidget(self):
+        """Deprecated alias for :meth:`widget`."""
+        return self.widget()
+
     def _ipython_display_(self):
         """Auto-display as the interactive widget when possible.
 
-        Falls back to a plain ``repr`` when ``anywidget`` /
-        ``ipywidgets`` is not available - Jupyter will then use the
-        normal text representation.
+        Falls back to a plain ``repr`` when ``anywidget`` is not
+        available — Jupyter will then use the normal text representation.
+
+        Not called by marimo; marimo users should return the widget from
+        a cell (e.g. ``library.widget()``).
         """
         try:
-            widget = self.ipywidget()
+            widget = self.widget()
         except ImportError:
             # No optional deps; let Jupyter fall back to repr().
             print(repr(self))
             return
-        from IPython.display import display
-
+        try:
+            from IPython.display import display
+        except ImportError:  # pragma: no cover - IPython not installed
+            print(repr(self))
+            return
         display(widget)
 
 
diff --git a/src/projspec/proj/base.py b/src/projspec/proj/base.py
index 511fcb1..ef55ca8 100644
--- a/src/projspec/proj/base.py
+++ b/src/projspec/proj/base.py
@@ -635,9 +635,8 @@ def to_dict(self, compact=True) -> dict:
     def _ipython_display_(self):
         """Auto-display as the interactive widget when possible.
 
-        Falls back to a plain ``repr`` when ``anywidget`` /
-        ``ipywidgets`` is not available - Jupyter will then use the
-        normal text representation.
+        Falls back to a plain ``repr`` when ``anywidget`` is not
+        available - Jupyter will then use the normal text representation.
         """
         from projspec.library import ProjectLibrary
 
diff --git a/src/projspec/webui/ipywidget.py b/src/projspec/webui/ipywidget.py
index 580c7f4..5133eb3 100644
--- a/src/projspec/webui/ipywidget.py
+++ b/src/projspec/webui/ipywidget.py
@@ -1,10 +1,14 @@
-"""Jupyter ``ipywidget`` representation of :class:`ProjectLibrary`.
+"""Jupyter / marimo widget representation of :class:`ProjectLibrary`.
 
 This module owns the *host* side of the shared webui transport for the
-Jupyter Notebook / JupyterLab / VSCode-notebook / Colab environments.  It
-builds an :mod:`anywidget` ``AnyWidget`` that loads the shared HTML, CSS
-and JS from :mod:`projspec.webui` and drives it from Python with the same
-command vocabulary as the VSCode extension and the Qt app.
+Jupyter Notebook / JupyterLab / VSCode-notebook / Colab / marimo
+environments.  It builds an :mod:`anywidget` ``AnyWidget`` that loads the
+shared HTML, CSS and JS from :mod:`projspec.webui` and drives it from
+Python with the same command vocabulary as the VSCode extension and the
+Qt app.
+
+Only :mod:`anywidget` is required — :mod:`ipywidgets` is **not** needed,
+which means the widget runs under marimo as well as classic Jupyter.
 
 Current limitations
 -------------------
@@ -120,6 +124,12 @@
         try { el.removeChild(root); } catch {}
     };
 }
+
+// AFM spec requires a default export; the named `render` export is
+// deprecated in anywidget ≥ 0.9.13 and not recognised by some hosts
+// (e.g. marimo).  Export both so the module satisfies current validators
+// while remaining backward-compatible with older anywidget runtimes.
+export default { render };
 """
 
 
@@ -179,13 +189,12 @@ def _build_widget(library: "ProjectLibrary"):
     """
     try:
         import anywidget
-        import traitlets
     except ImportError as exc:  # pragma: no cover - optional dep
         raise ImportError(
             "The ipywidget representation of ProjectLibrary requires the "
-            "'anywidget' and 'ipywidgets' packages.  Install them with "
+            "'anywidget' package.  Install it with "
             "``pip install projspec[ipywidget]`` or "
-            "``pip install anywidget ipywidgets``."
+            "``pip install anywidget``."
         ) from exc
 
     class ProjectLibraryWidget(anywidget.AnyWidget):
@@ -198,10 +207,10 @@ class ProjectLibraryWidget(anywidget.AnyWidget):
         """
 
         _esm = _build_esm()
-        # CSS is embedded in the ESM; traitlets.Unicode default is fine.
+        # CSS is embedded in the ESM; anywidget ignores an empty _css.
         _css = ""
 
-        # No traitlets-level state: the widget exchanges messages via
+        # No traitlets state: the widget exchanges messages via
         # ``send`` / ``msg:custom`` instead of syncing a model attribute.
 
         def __init__(self, library_obj: "ProjectLibrary", **kwargs: Any):
@@ -709,7 +718,7 @@ def walk(cls: type) -> None:
 def make_widget(library: "ProjectLibrary"):
     """Return an anywidget-backed DOMWidget for ``library``.
 
-    Public entry point used by :meth:`ProjectLibrary.ipywidget`.
+    Public entry point used by :meth:`ProjectLibrary.widget`.
     """
     return _build_widget(library)
 
diff --git a/tests/test_ipywidget_helpers.py b/tests/test_ipywidget_helpers.py
index ce84131..3967db2 100644
--- a/tests/test_ipywidget_helpers.py
+++ b/tests/test_ipywidget_helpers.py
@@ -1,6 +1,6 @@
 """Tests for module-level helpers in projspec.webui.ipywidget.
 
-These functions have no dependency on anywidget, ipywidgets, or a live
+These functions have no dependency on anywidget or a live
 Jupyter kernel, so they run in any environment.  Widget-construction tests
 that *do* require anywidget remain in test_webui.py.
 
@@ -334,7 +334,7 @@ def widget_and_lib(tmp_path):
     proj_url = "file://" + proj_path
     lib.entries[proj_url] = projspec.Project(proj_path, walk=False)
 
-    widget = lib.ipywidget()
+    widget = lib.widget()
     widget.send = lambda c, buffers=None: None
     widget._toast = lambda m: None
     return widget, lib, proj_url
@@ -486,7 +486,7 @@ def test_resolve_entry_path_remote_keeps_protocol(self, tmp_path):
             key = proj.fs.unstrip_protocol(proj.url)
             lib.entries[key] = proj
 
-            widget = lib.ipywidget()
+            widget = lib.widget()
             widget.send = lambda c, buffers=None: None
             widget._toast = lambda m: None
 
@@ -543,7 +543,7 @@ def test_resolve_entry_path_old_library_keeps_protocol(self, tmp_path):
             # sanity: the reconstructed entry's fs is (wrongly) local here
             assert lib.entries["memory:///ipw_old"].is_local()
 
-            widget = lib.ipywidget()
+            widget = lib.widget()
             widget.send = lambda c, buffers=None: None
             widget._toast = lambda m: None
 
diff --git a/tests/test_webui.py b/tests/test_webui.py
index bb11b2d..31722c8 100644
--- a/tests/test_webui.py
+++ b/tests/test_webui.py
@@ -2,7 +2,7 @@
 
 These tests don't require a browser or a real Jupyter kernel: we just
 check that the static resources are self-consistent and that the
-``ProjectLibrary.ipywidget`` plumbing degrades gracefully when the
+``ProjectLibrary.widget`` plumbing degrades gracefully when the
 optional ``anywidget`` dependency is unavailable.
 """
 
@@ -86,14 +86,14 @@ def test_panel_css_and_js_are_strings():
 
 
 def test_ipywidget_degrades_when_anywidget_missing(monkeypatch, tmp_path):
-    """Without anywidget / ipywidgets, .ipywidget() raises ImportError
+    """Without anywidget, .widget() raises ImportError
     and _ipython_display_ falls back to printing the repr."""
     try:
         import anywidget  # noqa: F401
     except ImportError:
         lib = ProjectLibrary(str(tmp_path / "lib.json"), auto_save=False)
         with pytest.raises(ImportError):
-            lib.ipywidget()
+            lib.widget()
 
 
 def test_ipywidget_esm_builds():
@@ -116,13 +116,12 @@ def test_ipywidget_esm_builds():
 
 
 def test_ipywidget_construction_if_available(tmp_path):
-    """If anywidget is available, ProjectLibrary.ipywidget() returns a
+    """If anywidget is available, ProjectLibrary.widget() returns a
     widget with a non-empty _esm."""
     anywidget = pytest.importorskip("anywidget")
-    pytest.importorskip("ipywidgets")
 
     lib = ProjectLibrary(str(tmp_path / "lib.json"), auto_save=False)
-    widget = lib.ipywidget()
+    widget = lib.widget()
     assert isinstance(widget, anywidget.AnyWidget)
     assert widget._esm and "export function render" in widget._esm
 
@@ -136,7 +135,6 @@ def test_ipywidget_handlers_respond(tmp_path):
     report as 'the button doesn't work'.
     """
     pytest.importorskip("anywidget")
-    pytest.importorskip("ipywidgets")
     from projspec import Project
 
     lib_file = tmp_path / "lib.json"
@@ -148,7 +146,7 @@ def test_ipywidget_handlers_respond(tmp_path):
     proj_url = "file://" + proj_path
     lib.entries[proj_url] = Project(proj_path, walk=False)
 
-    widget = lib.ipywidget()
+    widget = lib.widget()
     outbox: list[dict] = []
     toasts: list[str] = []
     widget.send = lambda content, buffers=None: outbox.append(content)
@@ -257,7 +255,6 @@ def test_make_cwd_uses_project_path_not_library_key(tmp_path, monkeypatch):
     import fsspec
 
     pytest.importorskip("anywidget")
-    pytest.importorskip("ipywidgets")
     from projspec.artifact.process import Process
     from projspec.proj.base import Project, ProjectSpec
     from projspec.utils import AttrDict, is_installed
@@ -297,7 +294,7 @@ def test_make_cwd_uses_project_path_not_library_key(tmp_path, monkeypatch):
 
     # Kernel cwd is deliberately somewhere else.
     monkeypatch.chdir("/")
-    w = lib.ipywidget()
+    w = lib.widget()
     w._toast = lambda m: None
     w.send = lambda c, buffers=None: None