diff --git a/setup.cfg b/setup.cfg
index 6b2a432..64ab1b8 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -31,12 +31,13 @@ project_urls =
 [options]
 packages = find:
 install_requires =
+    cryoet_data_portal
+    fsspec[http,s3]
     npe2
     numpy
     napari_ome_zarr
     ndjson
     qtpy
-    s3fs
     superqt
 
 python_requires = >=3.8
diff --git a/src/napari_cryoet_data_portal/__init__.py b/src/napari_cryoet_data_portal/__init__.py
index 59080ac..9a1fca1 100644
--- a/src/napari_cryoet_data_portal/__init__.py
+++ b/src/napari_cryoet_data_portal/__init__.py
@@ -2,10 +2,11 @@
     from ._version import version as __version__
 except ImportError:
     __version__ = "unknown"
-from ._logging import logger
 from ._reader import (
     points_annotations_reader,
-    read_points_annotations_json,
+    read_annotation,
+    read_points_annotations_ndjson,
+    read_tomogram,
     read_tomogram_ome_zarr,
     tomogram_ome_zarr_reader,
 )
@@ -14,7 +15,9 @@
 __all__ = (
     "DataPortalWidget",
     "points_annotations_reader",
+    "read_annotation",
+    "read_tomogram",
     "read_tomogram_ome_zarr",
-    "read_points_annotations_json",
+    "read_points_annotations_ndjson",
     "tomogram_ome_zarr_reader",
 )
diff --git a/src/napari_cryoet_data_portal/_io.py b/src/napari_cryoet_data_portal/_io.py
deleted file mode 100644
index c119c9b..0000000
--- a/src/napari_cryoet_data_portal/_io.py
+++ /dev/null
@@ -1,56 +0,0 @@
-"""IO utilities for abstracting paths across S3, HTTPS, and a local filesystem."""
-
-import json
-import os
-from typing import Any, Callable, Dict, List, Tuple
-
-from s3fs import S3FileSystem
-
-
-def list_dir(path: str) -> Tuple[str, ...]:
-    """Returns the names of the contents of a directory-like path."""
-    names = _list_dir_s3(path) if _is_s3(path) else os.listdir(path)
-    return tuple(sorted(names))
-
-
-def path_exists(path: str) -> bool:
-    """Returns true if the given path exists, false otherwise."""
-    return _path_exists_s3(path) if _is_s3(path) else os.path.exists(path)
-
-
-def get_open(path: str) -> Callable[[str], Any]:
-    """Returns a function to open a file at the given path."""
-    if _is_s3(path):
-        s3 = S3FileSystem(anon=True)
-        return s3.open
-    return open
-
-
-def s3_to_https(path: str) -> str:
-    """Converts an S3 URI to the equivalent CloudFront HTTPS URI."""
-    return path.replace(
-        "s3://cryoet-data-portal-public",
-        "https://files.cryoetdataportal.cziscience.com",
-    )
-
-
-def read_json(path: str) -> Dict[str, Any]:
-    """Reads JSON from the given path."""
-    open_ = get_open(path)
-    with open_(path) as f:
-        return json.load(f)
-
-
-def _is_s3(path: str) -> bool:
-    return path.startswith("s3://")
-
-
-def _path_exists_s3(path: str) -> bool:
-    s3 = S3FileSystem(anon=True)
-    return s3.exists(path)
-
-
-def _list_dir_s3(path: str) -> List[str]:
-    s3 = S3FileSystem(anon=True)
-    bucket_path = path.replace("s3://", "")
-    return [p.split("/")[-1] for p in s3.ls(bucket_path)]
diff --git a/src/napari_cryoet_data_portal/_listing_widget.py b/src/napari_cryoet_data_portal/_listing_widget.py
index 4e2892c..64a2e1c 100644
--- a/src/napari_cryoet_data_portal/_listing_widget.py
+++ b/src/napari_cryoet_data_portal/_listing_widget.py
@@ -1,4 +1,4 @@
-from typing import Generator, Optional
+from typing import Generator, List, Optional, Tuple
 
 from qtpy.QtCore import Qt
 from qtpy.QtWidgets import (
@@ -8,11 +8,10 @@
     QVBoxLayout,
     QWidget,
 )
+from cryoet_data_portal import Client, Dataset, Tomogram
 
-from napari_cryoet_data_portal._io import list_dir
 from napari_cryoet_data_portal._listing_tree_widget import ListingTreeWidget
 from napari_cryoet_data_portal._logging import logger
-from napari_cryoet_data_portal._model import Dataset
 from napari_cryoet_data_portal._progress_widget import ProgressWidget
 from napari_cryoet_data_portal._vendored.superqt._searchable_tree_widget import (
     _update_visible_items,
@@ -44,37 +43,37 @@ def __init__(self, parent: Optional[QWidget] = None) -> None:
         layout.addStretch(0)
         self.setLayout(layout)
 
-    def load(self, path: str) -> None:
-        """Lists the datasets and tomograms at the given data portal path."""
-        logger.debug("ListingWidget.load: %s", path)
+    def load(self, uri: str) -> None:
+        """Lists the datasets and tomograms using the given portal URI."""
+        logger.debug("ListingWidget.load: %s", uri)
         self.tree.clear()
         self.show()
-        self._progress.submit(path)
+        self._progress.submit(uri)
 
     def cancel(self) -> None:
         """Cancels the last listing."""
         logger.debug("ListingWidget.cancel")
         self._progress.cancel()
 
-    def _loadDatasets(self, path: str) -> Generator[Dataset, None, None]:
-        logger.debug("ListingWidget._loadDatasets: %s", path)
-        # TODO: only list non-hidden directories.
-        dataset_names = tuple(
-            p for p in list_dir(path) if not p.startswith(".")
-        )
-        if len(dataset_names) == 0:
-            logger.debug("No datasets found")
-        for name in dataset_names:
-            yield Dataset.from_data_path_and_name(path, name)
+    def _loadDatasets(self, uri: str) -> Generator[Tuple[Dataset, List[Tomogram]], None, None]:
+        logger.debug("ListingWidget._loadDatasets: %s", uri)
+        client = Client(uri)
+        for dataset in Dataset.find(client):
+            tomograms: List[Tomogram] = []
+            for run in dataset.runs:
+                for spacing in run.tomogram_voxel_spacings:
+                    tomograms.extend(spacing.tomograms)
+            yield dataset, tomograms
 
-    def _onDatasetLoaded(self, dataset: Dataset) -> None:
-        logger.debug("ListingWidget._onDatasetLoaded: %s", dataset.name)
-        text = f"{dataset.name} ({len(dataset.tomograms)})"
+    def _onDatasetLoaded(self, result: Tuple[Dataset, List[Tomogram]]) -> None:
+        dataset, tomograms = result
+        logger.debug("ListingWidget._onDatasetLoaded: %s", dataset.id)
+        text = f"{dataset.id} ({len(tomograms)})"
         item = QTreeWidgetItem((text,))
         item.setData(0, Qt.ItemDataRole.UserRole, dataset)
-        for s in dataset.tomograms:
-            tomogram_item = QTreeWidgetItem((s.name,))
-            tomogram_item.setData(0, Qt.ItemDataRole.UserRole, s)
+        for tomogram in tomograms:
+            tomogram_item = QTreeWidgetItem((tomogram.name,))
+            tomogram_item.setData(0, Qt.ItemDataRole.UserRole, tomogram)
             item.addChild(tomogram_item)
         _update_visible_items(item, self.tree.last_filter)
         self.tree.addTopLevelItem(item)
diff --git a/src/napari_cryoet_data_portal/_metadata_widget.py b/src/napari_cryoet_data_portal/_metadata_widget.py
index 9634a6f..94bae45 100644
--- a/src/napari_cryoet_data_portal/_metadata_widget.py
+++ b/src/napari_cryoet_data_portal/_metadata_widget.py
@@ -5,10 +5,9 @@
     QVBoxLayout,
     QWidget,
 )
+from cryoet_data_portal import Dataset, Tomogram
 
-from napari_cryoet_data_portal._io import read_json
 from napari_cryoet_data_portal._logging import logger
-from napari_cryoet_data_portal._model import Dataset, Tomogram
 from napari_cryoet_data_portal._progress_widget import ProgressWidget
 from napari_cryoet_data_portal._vendored.superqt._searchable_tree_widget import (
     QSearchableTreeWidget,
@@ -39,7 +38,8 @@ def load(self, data: Union[Dataset, Tomogram]) -> None:
         """Loads the JSON metadata of the given dataset or tomogram."""
         logger.debug("MetadataWidget.load: %s", data)
         self._main.tree.clear()
-        self.setTitle(f"Metadata: {data.name}")
+        name = data.id if isinstance(data, Dataset) else data.name
+        self.setTitle(f"Metadata: {name}")
         self.show()
         self._progress.submit(data)
 
@@ -50,14 +50,7 @@ def cancel(self) -> None:
 
     def _loadMetadata(self, data: Union[Dataset, Tomogram]) -> Dict[str, Any]:
         logger.debug("MetadataWidget._loadMetadata: %s", data)
-        path = ""
-        if isinstance(data, Dataset):
-            path = data.metadata_path
-        elif isinstance(data, Tomogram):
-            path = data.tomogram_metadata_path
-        else:
-            raise AssertionError("Expected Dataset or Tomogram data")
-        return read_json(path)
+        return data.to_dict()
 
     def _onMetadataLoaded(self, metadata: Dict[str, Any]) -> None:
         logger.debug("MetadataWidget._onMetadataLoaded: %s", metadata)
diff --git a/src/napari_cryoet_data_portal/_model.py b/src/napari_cryoet_data_portal/_model.py
deleted file mode 100644
index 3fa878c..0000000
--- a/src/napari_cryoet_data_portal/_model.py
+++ /dev/null
@@ -1,113 +0,0 @@
-"""Data model used to abstract the contents and structure of the portal."""
-
-from dataclasses import dataclass, field
-from functools import cached_property
-from typing import Tuple
-
-from napari_cryoet_data_portal._io import list_dir
-
-PORTAL_S3_URI = "s3://cryoet-data-portal-public"
-
-# TODO: hardcoding these correspondences as a short term fix
-# for the recent bucket layout change which avoids an extra listing
-# call to s3. Need a long term fix here, which likely uses the main
-# Python client.
-DATASET_TO_SPACING = {
-    '10000': 'VoxelSpacing13.48',
-    '10001': 'VoxelSpacing13.48',
-    '10004': 'VoxelSpacing7.56',
-}
-DEFAULT_SPACING = 'VoxelSpacing13.48'
-
-
-@dataclass(frozen=True)
-class Tomogram:
-    """Represents a tomogram within a dataset.
-
-    Attributes
-    ----------
-    name : str
-        The name of the tomogram (e.g. 'TS_026').
-    path : str
-        The full directory-like path associated with the tomogram 
-        (e.g. 's3://cryoet-data-portal-public/10000/TS_026').
-    tomogram_path : str
-        The full directory-like path to the tomogram directory that contains the volumes and annotations
-        (e.g. 's3://cryoet-data-portal-public/10000/TS_026/Tomograms/VoxelSpacing13.48').
-    image_path : str
-        The full directory-like path to the tomogram as an OME-Zarr multi-scale image
-        (e.g. 's3://cryoet-data-portal-public/10000/TS_026/Tomograms/VoxelSpacing13.48/CanonicalTomogram/TS_026.zarr').
-    annotation_paths : tuple of str
-        The full file-like paths to the annotation JSON files
-        (e.g. ['s3://cryoet-data-portal-public/10000/TS_026/Tomograms/VoxelSpacing13.48/Annotations/sara_goetz-ribosome-1.0.json', ...]).
-    """
-
-    name: str
-    path: str
-    tomogram_path: str
-    image_path: str
-    annotation_paths: Tuple[str, ...]
-
-    @cached_property
-    def tomogram_metadata_path(self) -> str:
-        return (
-            f"{self.tomogram_path}/CanonicalTomogram/tomogram_metadata.json"
-        )
-
-    @classmethod
-    def from_dataset_path_and_name(
-        cls, dataset_path: str, name: str
-    ) -> "Tomogram":
-        path = f"{dataset_path}/{name}"
-        dataset_name = dataset_path.split('/')[-1]
-        spacing = DATASET_TO_SPACING.get(dataset_name, DEFAULT_SPACING)
-        tomogram_path = f"{path}/Tomograms/{spacing}"
-        image_path = f"{tomogram_path}/CanonicalTomogram/{name}.zarr"
-        annotation_dir = f"{tomogram_path}/Annotations"
-        annotation_paths = tuple(
-            f"{annotation_dir}/{p}"
-            for p in list_dir(annotation_dir)
-            if p.endswith(".json")
-        )
-        return cls(
-            name=name,
-            path=path,
-            tomogram_path=tomogram_path,
-            image_path=image_path,
-            annotation_paths=annotation_paths,
-        )
-
-
-@dataclass(frozen=True)
-class Dataset:
-    """Represents an entire dataset of many tomograms and their annotations.
-
-    Attributes
-    ----------
-    name : str
-        The name of the dataset (e.g. '10000').
-    path : str
-        The full directory-like path associated with the dataset
-        (e.g. 's3://cryoet-data-portal-public/10000').
-    tomograms : tuple of tomograms
-        The tomograms within the dataset.
-    """
-
-    name: str
-    path: str
-    tomograms: Tuple[Tomogram, ...] = field(repr=False)
-
-    @cached_property
-    def metadata_path(self) -> str:
-        return f"{self.path}/dataset_metadata.json"
-
-    @classmethod
-    def from_data_path_and_name(cls, data_path: str, name: str) -> "Dataset":
-        path = f"{data_path}/{name}"
-        tomograms = tuple(
-            Tomogram.from_dataset_path_and_name(path, p)
-            for p in list_dir(path)
-            # TODO: better way to select non-hidden directories.
-            if "." not in p
-        )
-        return Dataset(name=name, path=path, tomograms=tomograms)
diff --git a/src/napari_cryoet_data_portal/_open_widget.py b/src/napari_cryoet_data_portal/_open_widget.py
index c8a3d4d..1508569 100644
--- a/src/napari_cryoet_data_portal/_open_widget.py
+++ b/src/napari_cryoet_data_portal/_open_widget.py
@@ -13,13 +13,13 @@
     QVBoxLayout,
     QWidget,
 )
+from cryoet_data_portal import Annotation, Client, Tomogram
 
 from napari_cryoet_data_portal._logging import logger
-from napari_cryoet_data_portal._model import Tomogram
 from napari_cryoet_data_portal._progress_widget import ProgressWidget
 from napari_cryoet_data_portal._reader import (
-    read_points_annotations_json,
-    read_tomogram_ome_zarr,
+    read_annotation,
+    read_tomogram,
 )
 
 if TYPE_CHECKING:
@@ -39,7 +39,7 @@ class Resolution:
 MID_RESOLUTION = Resolution(name="Mid", indices=(1,), scale=2)
 LOW_RESOLUTION = Resolution(name="Low", indices=(2,), scale=4)
 
-RESOLUTIONS: Tuple[Resolution] = (
+RESOLUTIONS: Tuple[Resolution, ...] = (
     MULTI_RESOLUTION,
     HIGH_RESOLUTION,
     MID_RESOLUTION,
@@ -56,7 +56,8 @@ def __init__(
         super().__init__(parent)
 
         self._viewer = viewer
-        self._tomogram : Optional[Tomogram] = None
+        self._uri: Optional[str] = None
+        self._tomogram: Optional[Tomogram] = None
 
         self.setTitle("Tomogram")
 
@@ -88,6 +89,10 @@ def __init__(
         layout.addWidget(self._progress)
         self.setLayout(layout)
 
+    def setUri(self, uri: str) -> None:
+        """Sets the URI of the portal that should be used to open data."""
+        self._uri = uri
+
     def setTomogram(self, tomogram: Tomogram) -> None:
         """Sets the current tomogram that should be opened."""
         self.cancel()
@@ -117,9 +122,7 @@ def _loadTomogram(
         resolution: Resolution,
     ) -> Generator[FullLayerData, None, None]:
         logger.debug("OpenWidget._loadTomogram: %s", tomogram.name)
-        image_data, image_attrs, _ = read_tomogram_ome_zarr(tomogram.image_path)
-        # TODO: read JSON metadata in reader to get name from there.
-        image_attrs["name"] = f"{tomogram.name}-tomogram"
+        image_data, image_attrs, _ = read_tomogram(tomogram)
         # Skip indexing for multi-resolution to avoid adding any
         # unnecessary nodes to the dask compute graph.
         if resolution is not MULTI_RESOLUTION:
@@ -132,11 +135,17 @@ def _loadTomogram(
         )
         yield image_data, image_attrs, "image"
 
-        for p in tomogram.annotation_paths:
-            points_data, points_attrs, _ = read_points_annotations_json(p)
-            annotation_name = points_attrs["name"]
-            points_attrs["name"] = f"{tomogram.name}-{annotation_name}"
-            yield points_data, points_attrs, "points"
+        # Looking up tomogram.tomogram_voxel_spacing.annotations triggers a query
+        # using the client from where the tomogram was found.
+        # A single client is not thread safe, so we need a new instance for each query.
+        client = Client(self._uri)
+        annotations = Annotation.find(
+            client, 
+            [Annotation.tomogram_voxel_spacing_id == tomogram.tomogram_voxel_spacing_id],
+        )
+
+        for annotation in annotations:
+            yield read_annotation(annotation, tomogram=tomogram)
 
     def _onLayerLoaded(self, layer_data: FullLayerData) -> None:
         logger.debug("OpenWidget._onLayerLoaded")
diff --git a/src/napari_cryoet_data_portal/_reader.py b/src/napari_cryoet_data_portal/_reader.py
index ee516d5..a5fb55a 100644
--- a/src/napari_cryoet_data_portal/_reader.py
+++ b/src/napari_cryoet_data_portal/_reader.py
@@ -1,22 +1,20 @@
 """Functions to read data from the portal into napari types."""
 
-import json
-import os
 from typing import Any, Dict, List, Optional, Tuple
+import fsspec
 
 import ndjson
 from napari_ome_zarr import napari_get_reader
 from npe2.types import FullLayerData, PathOrPaths, ReaderFunction
-
-from napari_cryoet_data_portal._io import get_open, s3_to_https
+from cryoet_data_portal import Annotation, Tomogram
 
 
 OBJECT_COLOR = {
-    'ribosome': 'red',
-    'ribosome, 80 s': 'red',
-    'fatty acid synthase': 'darkblue',
+    "ribosome": "red",
+    "ribosome, 80 s": "red",
+    "fatty acid synthase": "darkblue",
 }
-DEFAULT_OBJECT_COLOR = 'red'
+DEFAULT_OBJECT_COLOR = "red"
 
 
 def tomogram_ome_zarr_reader(path: PathOrPaths) -> Optional[ReaderFunction]:
@@ -71,24 +69,49 @@ def read_tomogram_ome_zarr(path: str) -> FullLayerData:
 
     Examples
     --------
-    >>> from napari.layers import Image
     >>> path = 's3://cryoet-data-portal-public/10000/TS_026/Tomograms/VoxelSpacing13.48/CanonicalTomogram/TS_026.zarr'
     >>> data, attrs, _ = read_tomogram_ome_zarr(path)
     >>> image = Image(data, **attrs)
     """
-    path = s3_to_https(path)
     reader = napari_get_reader(path)
     layers = reader(path)
     return layers[0]
 
 
+def read_tomogram(tomogram: Tomogram) -> FullLayerData:
+    """Reads a napari image layer from a tomogram.
+
+    Parameters
+    ----------
+    tomogram : Tomogram
+        The tomogram to read.
+
+    Returns
+    -------
+    napari layer data tuple
+        The data, attributes, and type name of the image layer that would be
+        returned by `Image.as_layer_data_tuple`.
+
+    Examples
+    --------
+    >>> client = Client()
+    >>> tomogram = client.find_one(Tomogram)
+    >>> data, attrs, _ = read_tomogram(tomogram)
+    >>> image = Image(data, **attrs)
+    """
+    data, attributes, layer_type = read_tomogram_ome_zarr(tomogram.https_omezarr_dir)
+    attributes["name"] = tomogram.name
+    attributes["metadata"] = tomogram.to_dict()
+    return data, attributes, layer_type
+
+
 def points_annotations_reader(path: PathOrPaths) -> Optional[ReaderFunction]:
     """napari plugin entry point for reading points annotations.
 
     Parameters
     ----------
     path : str or sequence of str
-        The path or paths of the annotation JSON file(s) to read.
+        The path or paths of the annotation NDJSON file(s) to read.
 
     Returns
     -------
@@ -109,22 +132,22 @@ def points_annotations_reader(path: PathOrPaths) -> Optional[ReaderFunction]:
     >>> reader = points_annotations_reader(path)
     >>> layers = reader(path)
     """
-    return _read_many_points_annotations
+    return _read_many_points_annotations_ndjson
 
 
-def _read_many_points_annotations(paths: PathOrPaths) -> List[FullLayerData]:
+def _read_many_points_annotations_ndjson(paths: PathOrPaths) -> List[FullLayerData]:
     if isinstance(paths, str):
         paths = [paths]
-    return [read_points_annotations_json(p) for p in paths]
+    return [read_points_annotations_ndjson(p) for p in paths]
 
 
-def read_points_annotations_json(path: str) -> FullLayerData:
-    """Reads a napari points layer from one annotation JSON File.
+def read_points_annotations_ndjson(path: str) -> FullLayerData:
+    """Reads a napari points layer from an NDJSON annotation file.
 
     Parameters
     ----------
     path : str
-        The path of the annotation JSON file to read.
+        The path to the NDJSON annotations file.
 
     Returns
     -------
@@ -134,41 +157,60 @@ def read_points_annotations_json(path: str) -> FullLayerData:
 
     Examples
     --------
-    >>> from napari.layers import Points
     >>> path = 's3://cryoet-data-portal-public/10000/TS_026/Tomograms/VoxelSpacing13.48/Annotations/sara_goetz-ribosome-1.0.json'
-    >>> data, attrs, _ = read_points_annotations_json(path)
+    >>> data, attrs, _ = read_points_annotations_ndjson(path)
     >>> points = Points(data, **attrs)
     """
-    data: List[Tuple[float, float, float]] = []
-    open_ = get_open(path)
-    with open_(path) as f:
-        metadata = json.load(f)
-    data_dir = os.path.dirname(path)
-    for sub_file in metadata["files"]:
-        sub_name = sub_file["file"]
-        sub_path = f"{data_dir}/{sub_name}"
-        sub_data = _read_points_annotations_ndjson(sub_path)
-        data.extend(sub_data)
-    anno_object = metadata["annotation_object"]
-    name = anno_object["name"]
-    face_color = OBJECT_COLOR.get(name.lower(), DEFAULT_OBJECT_COLOR)
+    data = _read_points_data(path)
     attributes = {
-        "name": name,
-        "metadata": metadata,
+        "name": "annotations",
         "size": 14,
-        "face_color": face_color,
+        "face_color": "red",
         "opacity": 0.5,
         "out_of_slice_display": True,
     }
     return data, attributes, "points"
 
 
-def _read_points_annotations_ndjson(
+def read_annotation(annotation: Annotation, *, tomogram: Optional[Tomogram] = None) -> FullLayerData:
+    """Reads a napari points layer from an annotation.
+
+    Parameters
+    ----------
+    annotation : Annotation
+        The tomogram annotation.
+    tomogram : Tomogram, optional
+        The associated tomogram, which may be used for other metadata.
+
+    Returns
+    -------
+    napari layer data tuple
+        The data, attributes, and type name of the points layer that would be
+        returned by `Points.as_layer_data_tuple`.
+
+    Examples
+    --------
+    >>> client = Client()
+    >>> annotation = client.find_one(Annotation)
+    >>> data, attrs, _ = read_annotation(annotation)
+    >>> points = Points(data, **attrs)
+    """
+    data, attributes, layer_type = read_points_annotations_ndjson(annotation.https_annotations_path)
+    name = annotation.object_name
+    if tomogram is None:
+        attributes["name"] = name
+    else:
+        attributes["name"] = f"{tomogram.name}-{name}"
+    attributes["metadata"] = annotation.to_dict()
+    attributes["face_color"] = OBJECT_COLOR.get(name.lower(), DEFAULT_OBJECT_COLOR)
+    return data, attributes, layer_type
+
+
+def _read_points_data(
     path: str,
 ) -> List[Tuple[float, float, float]]:
     data: List[Tuple[float, float, float]] = []
-    open_ = get_open(path)
-    with open_(path) as f:
+    with fsspec.open(path) as f:
         sub_data = [
             _annotation_to_point(annotation)
             for annotation in ndjson.load(f)
diff --git a/src/napari_cryoet_data_portal/_sample_data.py b/src/napari_cryoet_data_portal/_sample_data.py
index 58d2968..9ab4dae 100644
--- a/src/napari_cryoet_data_portal/_sample_data.py
+++ b/src/napari_cryoet_data_portal/_sample_data.py
@@ -2,10 +2,11 @@
 
 import numpy as np
 from npe2.types import FullLayerData
+from cryoet_data_portal import Client, Tomogram, TomogramVoxelSpacing
 
 from napari_cryoet_data_portal import (
-    read_points_annotations_json,
-    read_tomogram_ome_zarr,
+    read_annotation,
+    read_tomogram,
 )
 
 
@@ -20,26 +21,21 @@ def tomogram_10000_ts_027() -> List[FullLayerData]:
 
 
 def _read_tomogram_from_10000(name: str) -> List[FullLayerData]:
-    base_uri = f"s3://cryoet-data-portal-public/10000/{name}/Tomograms/VoxelSpacing13.48"
-    tomogram_uri = f"{base_uri}/CanonicalTomogram/{name}.zarr"
-    annotations_uri = f"{base_uri}/Annotations"
-    ribosome_uri = f"{annotations_uri}/sara_goetz-ribosome-1.0.json"
-    fatty_acid_uri = (
-        f"{annotations_uri}/sara_goetz-fatty_acid_synthase-1.0.json"
-    )
-
-    tomogram_image = read_tomogram_ome_zarr(tomogram_uri)
+    client = Client()
+    
+    tomogram_spacing_url = f"https://files.cryoetdataportal.cziscience.com/10000/{name}/Tomograms/VoxelSpacing13.48/"
+    tomogram_spacing = next(TomogramVoxelSpacing.find(client, [TomogramVoxelSpacing.https_prefix == tomogram_spacing_url]))
+
+    tomogram: Tomogram = next(tomogram_spacing.tomograms)
+
+    tomogram_image = read_tomogram(tomogram)
     # Materialize lowest resolution for speed.
     tomogram_image = (np.asarray(tomogram_image[0][-1]), *tomogram_image[1:])
     tomogram_image[1]["scale"] = (4, 4, 4)
-    # TODO: fix this in reader or data.
-    tomogram_image[1]["name"] = "Tomogram"
-
-    ribosome_points = read_points_annotations_json(ribosome_uri)
 
-    fatty_acid_points = read_points_annotations_json(fatty_acid_uri)
-    # Make different annotations distinctive.
-    fatty_acid_points[1]["face_color"] = "blue"
+    annotations = tuple(tomogram_spacing.annotations)
+    ribosome_points = read_annotation(annotations[0], tomogram=tomogram)
+    fatty_acid_points = read_annotation(annotations[1], tomogram=tomogram)
 
     return [
         tomogram_image,
diff --git a/src/napari_cryoet_data_portal/_tests/_mocks.py b/src/napari_cryoet_data_portal/_tests/_mocks.py
deleted file mode 100644
index 53e74c8..0000000
--- a/src/napari_cryoet_data_portal/_tests/_mocks.py
+++ /dev/null
@@ -1,168 +0,0 @@
-from typing import Any, Dict, Tuple
-
-import numpy as np
-
-from napari_cryoet_data_portal._model import Dataset, Tomogram
-
-
-MOCK_S3_URI = 's3://mock-portal'
-
-
-def mock_dataset(
-    *,
-    name: str,
-    tomograms: Tuple[Tomogram, ...],
-) -> Dataset:
-    path = f"{MOCK_S3_URI}/{name}"
-    return Dataset(
-        name=name,
-        path=path,
-        tomograms=tomograms,
-    )
-
-
-def mock_tomogram(
-        *,
-        dataset_name: str,
-        tomogram_name: str,
-        voxel_spacing: str,
-        annotation_names: Tuple[str, ...]
-) -> Tomogram:
-    path = f"{MOCK_S3_URI}/{dataset_name}/{tomogram_name}"
-    tomogram_path = f"{path}/Tomograms/VoxelSpacing{voxel_spacing}"
-    image_path = f"{tomogram_path}/CanonicalTomogram/{tomogram_name}.zarr"
-    annotations_path = f"{tomogram_path}/Annotations"
-    annotations_paths = tuple(
-        f"{annotations_path}/{name}.json"
-        for name in annotation_names
-    )
-    return Tomogram(
-        name=tomogram_name,
-        path=path,
-        tomogram_path=tomogram_path,
-        image_path=image_path,
-        annotation_paths=annotations_paths,
-    )
-
-
-MOCK_TOMOGRAM_TS_026 = mock_tomogram(
-    dataset_name="10000",
-    tomogram_name="TS_026",
-    voxel_spacing="13.48",
-    annotation_names=("ribosome", "fatty-acid-synthase"),
-)
-
-MOCK_TOMOGRAM_TS_026_METADATA = {
-    'run_name': 'TS_026',
-    'voxel_spacing': 13.48,
-    'size': {
-        'z': 8,
-        'y': 8,
-        'x': 8,
-    }
-}
-
-MOCK_TOMOGRAM_TS_026_IMAGE_DATA = [
-    np.zeros((8, 8, 8)),
-    np.zeros((4, 4, 4)),
-    np.zeros((2, 2, 2)),
-]
-
-MOCK_TOMOGRAM_TS_026_IMAGE_ATTRS = {
-    'name': 'TS_026',
-    'scale': (1, 1, 1),
-}
-
-MOCK_TOMOGRAM_TS_026_RIBOSOME_DATA = [[0, 0, 0], [2, 2, 2]]
-MOCK_TOMOGRAM_TS_026_RIBOSOME_ATTRS = {'name': 'ribosome'}
-
-MOCK_TOMOGRAM_TS_026_FAS_DATA = [[1, 1, 1], [3, 3, 3]]
-MOCK_TOMOGRAM_TS_026_FAS_ATTRS = {'name': 'fatty acid synthase'}
-
-MOCK_TOMOGRAM_TS_027 = mock_tomogram(
-    dataset_name="10000",
-    tomogram_name="TS_027",
-    voxel_spacing="13.48",
-    annotation_names=("ribosome", "fatty-acid-synthase"),
-)
-
-MOCK_DATASET_10000 = mock_dataset(
-    name="10000",
-    tomograms=(MOCK_TOMOGRAM_TS_026, MOCK_TOMOGRAM_TS_027),
-)
-
-MOCK_DATASET_10000_METADATA = {
-    'dataset_title': 'mock dataset',
-    'authors': [
-        {
-            'name': 'mock author',
-            'ORCID': "0000-1111-2222-3333",
-        }
-    ],
-    'organism': {
-        'name': 'mock organism',
-    }
-}
-
-MOCK_TOMOGRAM_POS_128 = mock_tomogram(
-    dataset_name="10004",
-    tomogram_name="Position_128_2",
-    voxel_spacing="7.56",
-    annotation_names=("ribosome"),
-)
-
-MOCK_TOMOGRAM_POS_129 = mock_tomogram(
-    dataset_name="10004",
-    tomogram_name="Position_129_2",
-    voxel_spacing="7.56",
-    annotation_names=("ribosome"),
-)
-
-MOCK_DATASET_10004 = mock_dataset(
-    name="10004",
-    tomograms=(MOCK_TOMOGRAM_POS_128, MOCK_TOMOGRAM_POS_129),
-)
-
-MOCK_DATASETS = (MOCK_DATASET_10000, MOCK_DATASET_10004)
-
-
-def mock_path_exists(path: str) -> bool:
-    return path == MOCK_S3_URI
-
-
-def mock_list_dir(path: str) -> Tuple[str, ...]:
-    if path == f'{MOCK_S3_URI}':
-        return tuple(ds.name for ds in MOCK_DATASETS)
-    for ds in MOCK_DATASETS:
-        if ds.path == path:
-            return tuple(tomo.name for tomo in ds.tomograms)
-        for tomo in ds.tomograms:
-            anno_path = f"{tomo.tomogram_path}/Annotations"
-            if path == anno_path:
-                return tuple(
-                    p.split('/')[-1]
-                    for p in tomo.annotation_paths
-                )
-    raise ValueError(f"Mock path not supported: {path}")
-
-
-def mock_read_json(path: str) -> Dict[str, Any]:
-    if path == MOCK_DATASET_10000.metadata_path:
-        return MOCK_DATASET_10000_METADATA
-    if path == MOCK_TOMOGRAM_TS_026.tomogram_metadata_path:
-        return MOCK_TOMOGRAM_TS_026_METADATA
-    raise ValueError(f'Mock path not supported: {path}')
-
-
-def mock_read_tomogram_ome_zarr(path: str) -> Dict[str, Any]:
-    if path == MOCK_TOMOGRAM_TS_026.image_path:
-        return MOCK_TOMOGRAM_TS_026_IMAGE_DATA, MOCK_TOMOGRAM_TS_026_IMAGE_ATTRS, "image"
-    raise ValueError(f'Mock path not supported: {path}')
-
-
-def mock_read_points_annotations_json(path: str) -> Dict[str, Any]:
-    if path == MOCK_TOMOGRAM_TS_026.annotation_paths[0]:
-        return MOCK_TOMOGRAM_TS_026_RIBOSOME_DATA, MOCK_TOMOGRAM_TS_026_RIBOSOME_ATTRS, "points"
-    if path == MOCK_TOMOGRAM_TS_026.annotation_paths[1]:
-        return MOCK_TOMOGRAM_TS_026_FAS_DATA, MOCK_TOMOGRAM_TS_026_FAS_ATTRS, "points"
-    raise ValueError(f'Mock path not supported: {path}')
diff --git a/src/napari_cryoet_data_portal/_tests/conftest.py b/src/napari_cryoet_data_portal/_tests/conftest.py
new file mode 100644
index 0000000..d979be1
--- /dev/null
+++ b/src/napari_cryoet_data_portal/_tests/conftest.py
@@ -0,0 +1,18 @@
+import pytest
+
+from cryoet_data_portal import Client, Dataset, Tomogram
+
+
+@pytest.fixture()
+def client() -> Client:
+    return Client()
+
+
+@pytest.fixture()
+def dataset(client: Client) -> Dataset:
+    return next(Dataset.find(client, [Dataset.id == 10000]))
+
+
+@pytest.fixture()
+def tomogram(client: Client) -> Tomogram:
+    return next(Tomogram.find(client, [Tomogram.name == 'TS_026']))
\ No newline at end of file
diff --git a/src/napari_cryoet_data_portal/_tests/test_listing_widget.py b/src/napari_cryoet_data_portal/_tests/test_listing_widget.py
index 3badfe5..c28743e 100644
--- a/src/napari_cryoet_data_portal/_tests/test_listing_widget.py
+++ b/src/napari_cryoet_data_portal/_tests/test_listing_widget.py
@@ -1,17 +1,12 @@
 import pytest
-from pytest_mock import MockerFixture
 from pytestqt.qtbot import QtBot
 
 from napari_cryoet_data_portal._listing_widget import ListingWidget
-from napari_cryoet_data_portal._tests._mocks import (
-    MOCK_S3_URI,
-    mock_list_dir,
-)
 from napari_cryoet_data_portal._tests._utils import (
     tree_item_children,
-    tree_items_names,
     tree_top_items,
 )
+from napari_cryoet_data_portal._uri_widget import GRAPHQL_URI
 
 
 @pytest.fixture()
@@ -30,23 +25,12 @@ def test_init(qtbot: QtBot):
     assert not widget._progress.isVisibleTo(widget)
 
 
-def test_load_lists_data(widget: ListingWidget, mocker: MockerFixture, qtbot: QtBot):
-    mocker.patch(
-        'napari_cryoet_data_portal._listing_widget.list_dir',
-        mock_list_dir,
-    )
-    mocker.patch(
-        'napari_cryoet_data_portal._model.list_dir',
-        mock_list_dir,
-    )
-
-    with qtbot.waitSignal(widget._progress.finished):
-        widget.load(MOCK_S3_URI)
+def test_load_lists_data(widget: ListingWidget, qtbot: QtBot):
+    with qtbot.waitSignal(widget._progress.finished, timeout=60000):
+        widget.load(GRAPHQL_URI)
     
     dataset_items = tree_top_items(widget.tree)
-    assert tree_items_names(dataset_items) == ('10000 (2)', '10004 (2)')
-    tomogram_items_10000 = tree_item_children(dataset_items[0])
-    assert tree_items_names(tomogram_items_10000) == ('TS_026', 'TS_027')
-    tomogram_items_10001 = tree_item_children(dataset_items[1])
-    assert tree_items_names(tomogram_items_10001) == ('Position_128_2', 'Position_129_2')
+    assert len(dataset_items) > 0
+    tomogram_items = tree_item_children(dataset_items[0])
+    assert len(tomogram_items) > 0
     
\ No newline at end of file
diff --git a/src/napari_cryoet_data_portal/_tests/test_metadata_widget.py b/src/napari_cryoet_data_portal/_tests/test_metadata_widget.py
index e73d220..91eabb9 100644
--- a/src/napari_cryoet_data_portal/_tests/test_metadata_widget.py
+++ b/src/napari_cryoet_data_portal/_tests/test_metadata_widget.py
@@ -1,13 +1,9 @@
 import pytest
-from pytest_mock import MockerFixture
 from pytestqt.qtbot import QtBot
 
+from cryoet_data_portal import Dataset, Tomogram
+
 from napari_cryoet_data_portal._metadata_widget import MetadataWidget
-from napari_cryoet_data_portal._tests._mocks import (
-    MOCK_DATASET_10000,
-    MOCK_TOMOGRAM_TS_026,
-    mock_read_json,
-)
 from napari_cryoet_data_portal._tests._utils import tree_top_items
 
 
@@ -26,39 +22,17 @@ def test_init(qtbot: QtBot):
     assert not widget._progress.isVisibleTo(widget)
 
 
-def test_load_dataset_lists_metadata(widget: MetadataWidget, mocker: MockerFixture, qtbot: QtBot):
-    mocker.patch(
-        'napari_cryoet_data_portal._metadata_widget.read_json',
-        mock_read_json,
-    )
-
+def test_load_dataset_lists_metadata(widget: MetadataWidget, dataset: Dataset, qtbot: QtBot):
     with qtbot.waitSignal(widget._progress.finished):
-        widget.load(MOCK_DATASET_10000)
+        widget.load(dataset)
     
     items = tree_top_items(widget._main.tree)
-    
-    assert len(items) == 3
-    assert items[0].text(0) == 'dataset_title'
-    assert items[0].text(1) == 'mock dataset'
-    assert items[1].text(0) == 'authors'
-    assert items[2].text(0) == 'organism'
+    assert len(items) > 0
 
    
-def test_load_tomogram_lists_metadata(widget: MetadataWidget, mocker: MockerFixture, qtbot: QtBot):
-    mocker.patch(
-        'napari_cryoet_data_portal._metadata_widget.read_json',
-        mock_read_json,
-    )
-
+def test_load_tomogram_lists_metadata(widget: MetadataWidget, tomogram: Tomogram, qtbot: QtBot):
     with qtbot.waitSignal(widget._progress.finished):
-        widget.load(MOCK_TOMOGRAM_TS_026)
+        widget.load(tomogram)
     
     items = tree_top_items(widget._main.tree)
-    
-    assert len(items) == 3
-    assert items[0].text(0) == 'run_name'
-    assert items[0].text(1) == 'TS_026'
-    assert items[1].text(0) == 'voxel_spacing'
-    assert items[1].text(1) == '13.48'
-    assert items[2].text(0) == 'size'
-     
\ No newline at end of file
+    assert len(items) > 0
\ No newline at end of file
diff --git a/src/napari_cryoet_data_portal/_tests/test_model.py b/src/napari_cryoet_data_portal/_tests/test_model.py
deleted file mode 100644
index 559e61c..0000000
--- a/src/napari_cryoet_data_portal/_tests/test_model.py
+++ /dev/null
@@ -1,25 +0,0 @@
-from napari_cryoet_data_portal._model import PORTAL_S3_URI, Dataset, Tomogram
-
-
-def test_dataset_from_data_path_and_name():
-    dataset = Dataset.from_data_path_and_name(PORTAL_S3_URI, "10000")
-
-    assert dataset.name == "10000"
-    assert dataset.path == f"{PORTAL_S3_URI}/10000"
-    assert len(dataset.tomograms) > 0
-    tomogram_names = tuple(s.name for s in dataset.tomograms)
-    assert "TS_026" in tomogram_names
-
-
-def test_tomogram_from_dataset_path_and_name():
-    dataset_dir = f"{PORTAL_S3_URI}/10000"
-
-    tomogram = Tomogram.from_dataset_path_and_name(dataset_dir, "TS_026")
-
-    assert tomogram.name == "TS_026"
-    assert tomogram.path == f"{dataset_dir}/TS_026"
-    assert (
-        tomogram.image_path
-        == f"{dataset_dir}/TS_026/Tomograms/VoxelSpacing13.48/CanonicalTomogram/TS_026.zarr"
-    )
-    assert len(tomogram.annotation_paths) > 0
diff --git a/src/napari_cryoet_data_portal/_tests/test_open_widget.py b/src/napari_cryoet_data_portal/_tests/test_open_widget.py
index 4d2e205..8aa1b8f 100644
--- a/src/napari_cryoet_data_portal/_tests/test_open_widget.py
+++ b/src/napari_cryoet_data_portal/_tests/test_open_widget.py
@@ -1,14 +1,10 @@
 from napari.components import ViewerModel
 import pytest
-from pytest_mock import MockerFixture
 from pytestqt.qtbot import QtBot
 
+from cryoet_data_portal import Tomogram
+
 from napari_cryoet_data_portal._open_widget import OpenWidget
-from napari_cryoet_data_portal._tests._mocks import (
-    MOCK_TOMOGRAM_TS_026,
-    mock_read_points_annotations_json,
-    mock_read_tomogram_ome_zarr,
-)
 
 
 @pytest.fixture()
@@ -30,13 +26,11 @@ def test_init(viewer_model: ViewerModel, qtbot: QtBot):
     assert not widget._progress.isVisibleTo(widget)
 
 
-def test_set_tomogram_adds_layers_to_viewer(widget: OpenWidget, mocker: MockerFixture, qtbot: QtBot):
-    mocker.patch('napari_cryoet_data_portal._open_widget.read_tomogram_ome_zarr', mock_read_tomogram_ome_zarr)
-    mocker.patch('napari_cryoet_data_portal._open_widget.read_points_annotations_json', mock_read_points_annotations_json)
+def test_set_tomogram_adds_layers_to_viewer(widget: OpenWidget, tomogram: Tomogram, qtbot: QtBot):
     assert len(widget._viewer.layers) == 0
     
-    with qtbot.waitSignal(widget._progress.finished):
-        widget.setTomogram(MOCK_TOMOGRAM_TS_026)
+    with qtbot.waitSignal(widget._progress.finished, timeout=30000):
+        widget.setTomogram(tomogram)
     
     assert len(widget._viewer.layers) == 3
     
\ No newline at end of file
diff --git a/src/napari_cryoet_data_portal/_tests/test_reader.py b/src/napari_cryoet_data_portal/_tests/test_reader.py
index 2cee498..dbfaf1b 100644
--- a/src/napari_cryoet_data_portal/_tests/test_reader.py
+++ b/src/napari_cryoet_data_portal/_tests/test_reader.py
@@ -2,15 +2,16 @@
 
 from napari import Viewer
 from napari.layers import Points
+from cryoet_data_portal import Annotation, Client
 
 from napari_cryoet_data_portal import (
-    read_points_annotations_json,
+    read_points_annotations_ndjson,
     read_tomogram_ome_zarr,
 )
-from napari_cryoet_data_portal._model import PORTAL_S3_URI
 
-TOMOGRAM_DIR = f"{PORTAL_S3_URI}/10000/TS_026/Tomograms/VoxelSpacing13.48"
-ANNOTATION_FILE = f"{TOMOGRAM_DIR}/Annotations/sara_goetz-ribosome-1.0.json"
+CLOUDFRONT_URI = "https://files.cryoetdataportal.cziscience.com"
+TOMOGRAM_DIR = f"{CLOUDFRONT_URI}/10000/TS_026/Tomograms/VoxelSpacing13.48"
+ANNOTATION_FILE = f"{TOMOGRAM_DIR}/Annotations/sara_goetz-ribosome-1.0.ndjson"
 
 
 def test_read_tomogram_ome_zarr():
@@ -26,15 +27,14 @@ def test_read_tomogram_ome_zarr():
     assert layer_type == "image"
 
 
-def test_read_points_annotations_json():
-    data, attrs, layer_type = read_points_annotations_json(ANNOTATION_FILE)
+def test_read_points_annotations_ndjson():
+    data, attrs, layer_type = read_points_annotations_ndjson(ANNOTATION_FILE)
 
     assert len(data) == 838
     assert data[0] == (469, 261, 517)
     assert data[418] == (524, 831, 475)
     assert data[837] == (519, 723, 538)
-    assert attrs["name"] == "Ribosome"
-    assert attrs["face_color"] == "red"
+    assert attrs["name"] == "annotations"
     assert layer_type == "points"
 
 
diff --git a/src/napari_cryoet_data_portal/_tests/test_uri_widget.py b/src/napari_cryoet_data_portal/_tests/test_uri_widget.py
index d57efb8..1366c20 100644
--- a/src/napari_cryoet_data_portal/_tests/test_uri_widget.py
+++ b/src/napari_cryoet_data_portal/_tests/test_uri_widget.py
@@ -1,12 +1,7 @@
 import pytest
-from pytest_mock import MockerFixture
 from pytestqt.qtbot import QtBot
 
-from napari_cryoet_data_portal._uri_widget import UriWidget
-from napari_cryoet_data_portal._tests._mocks import (
-    MOCK_S3_URI,
-    mock_path_exists,
-)
+from napari_cryoet_data_portal._uri_widget import GRAPHQL_URI, UriWidget
 
 
 @pytest.fixture()
@@ -21,36 +16,26 @@ def test_init(qtbot: QtBot):
     qtbot.add_widget(widget)
 
     assert widget._connect_button.isVisibleTo(widget)
-    assert widget._choose_dir_button.isVisibleTo(widget)
     assert widget._uri_edit.isVisibleTo(widget)
     assert not widget._disconnect_button.isVisibleTo(widget)
     assert not widget._progress.isVisibleTo(widget)
 
 
-def test_click_connect_when_uri_exists(widget: UriWidget, qtbot: QtBot, mocker: MockerFixture):
-    mocker.patch(
-        'napari_cryoet_data_portal._uri_widget.path_exists',
-        mock_path_exists,
-    )
-    widget._uri_edit.setText(MOCK_S3_URI)
+def test_click_connect_when_uri_exists(widget: UriWidget, qtbot: QtBot):
+    widget._uri_edit.setText(GRAPHQL_URI)
 
     with qtbot.waitSignal(widget.connected):
         widget._connect_button.click()
 
     assert not widget._connect_button.isVisibleTo(widget)
-    assert not widget._choose_dir_button.isVisibleTo(widget)
     assert widget._uri_edit.isVisibleTo(widget)
-    assert widget._uri_edit.isReadOnly()
     assert widget._disconnect_button.isVisibleTo(widget)
     assert not widget._progress.isVisibleTo(widget)
 
 
-def test_click_connect_when_uri_does_not_exist(widget: UriWidget, qtbot: QtBot, mocker: MockerFixture):
-    mocker.patch(
-        'napari_cryoet_data_portal._uri_widget.path_exists',
-        mock_path_exists,
-    )
-    widget._uri_edit.setText('s3://mock-bad-uri')
+@pytest.mark.skip(reason="https://github.com/chanzuckerberg/cryoet-data-portal/issues/16")
+def test_click_connect_when_uri_does_not_exist(widget: UriWidget, qtbot: QtBot):
+    widget._uri_edit.setText("https://not.a.graphl.url/v1/graphql")
 
     with qtbot.captureExceptions() as exceptions:
         with qtbot.waitSignal(widget._progress.finished):
@@ -59,36 +44,18 @@ def test_click_connect_when_uri_does_not_exist(widget: UriWidget, qtbot: QtBot,
         assert exceptions[0][0] is ValueError
 
     assert widget._connect_button.isVisibleTo(widget)
-    assert widget._choose_dir_button.isVisibleTo(widget)
     assert widget._uri_edit.isVisibleTo(widget)
-    assert not widget._uri_edit.isReadOnly()
     assert not widget._disconnect_button.isVisibleTo(widget)
     assert not widget._progress.isVisibleTo(widget)
 
 
 def test_click_disconnect(widget: UriWidget, qtbot: QtBot):
-    widget._onUriChecked((True, MOCK_S3_URI))
+    widget._onConnected(GRAPHQL_URI)
 
     with qtbot.waitSignal(widget.disconnected):
         widget._disconnect_button.click()
 
     assert widget._connect_button.isVisibleTo(widget)
-    assert widget._choose_dir_button.isVisibleTo(widget)
     assert widget._uri_edit.isVisibleTo(widget)
-    assert not widget._uri_edit.isReadOnly()
     assert not widget._disconnect_button.isVisibleTo(widget)
-    assert not widget._progress.isVisibleTo(widget)
-
-
-def test_choose_dir_button_clicked(widget: UriWidget, mocker: MockerFixture):
-    mock_dir = '/path/to/test'
-    def mock_get_existing_directory(_):
-        return mock_dir
-    mocker.patch(
-        'napari_cryoet_data_portal._uri_widget.QFileDialog.getExistingDirectory',
-        mock_get_existing_directory,
-    )
-
-    widget._choose_dir_button.click()
-
-    assert widget._uri_edit.text() == mock_dir
\ No newline at end of file
+    assert not widget._progress.isVisibleTo(widget)
\ No newline at end of file
diff --git a/src/napari_cryoet_data_portal/_tests/test_widget.py b/src/napari_cryoet_data_portal/_tests/test_widget.py
index f220bdc..2643313 100644
--- a/src/napari_cryoet_data_portal/_tests/test_widget.py
+++ b/src/napari_cryoet_data_portal/_tests/test_widget.py
@@ -1,6 +1,7 @@
 from typing import Callable, List, Tuple
 
 import pytest
+from cryoet_data_portal import Client
 from napari import Viewer
 from napari.components import ViewerModel
 from pytest_mock import MockerFixture
@@ -8,6 +9,7 @@
 from qtpy.QtWidgets import QWidget
 
 from napari_cryoet_data_portal import DataPortalWidget
+from napari_cryoet_data_portal._uri_widget import GRAPHQL_URI
 
 
 @pytest.fixture()
@@ -60,11 +62,10 @@ def test_listing_item_changed_to_none(widget: DataPortalWidget):
 
 def test_connected_loads_listing(widget: DataPortalWidget, mocker: MockerFixture):
     mocker.patch.object(widget._listing, 'load')
-    uri = 's3://mock-portal'
 
-    widget._uri.connected.emit(uri)
+    widget._uri.connected.emit(GRAPHQL_URI)
 
-    widget._listing.load.assert_called_once_with(uri)
+    widget._listing.load.assert_called_once_with(GRAPHQL_URI)
 
 
 def test_disconnected_only_shows_uri(widget: DataPortalWidget):
diff --git a/src/napari_cryoet_data_portal/_uri_widget.py b/src/napari_cryoet_data_portal/_uri_widget.py
index b0330ed..d799181 100644
--- a/src/napari_cryoet_data_portal/_uri_widget.py
+++ b/src/napari_cryoet_data_portal/_uri_widget.py
@@ -1,27 +1,26 @@
-from typing import Optional, Tuple
+from typing import Optional
 
 from qtpy.QtCore import Signal
 from qtpy.QtWidgets import (
-    QFileDialog,
     QGroupBox,
     QHBoxLayout,
     QLineEdit,
     QPushButton,
-    QStyle,
     QVBoxLayout,
     QWidget,
 )
+from cryoet_data_portal import Client
 
-from napari_cryoet_data_portal._io import path_exists
 from napari_cryoet_data_portal._logging import logger
-from napari_cryoet_data_portal._model import PORTAL_S3_URI
 from napari_cryoet_data_portal._progress_widget import ProgressWidget
 
 
+GRAPHQL_URI = "https://graphql.cryoetdataportal.cziscience.com/v1/graphql"
+
 class UriWidget(QGroupBox):
     """Connects to a data portal with a specific URI."""
 
-    # Emitted on successful connection to the URI it contains.
+    # Emitted on successful connection with the URI.
     connected = Signal(str)
     # Emitted when disconnecting from the portal.
     disconnected = Signal()
@@ -32,22 +31,21 @@ def __init__(self, parent: Optional[QWidget] = None) -> None:
         self.setTitle("Portal")
         self._connect_button = QPushButton("Connect")
         self._disconnect_button = QPushButton("Disconnect")
-        self._uri_edit = QLineEdit(PORTAL_S3_URI)
+        self._uri_edit = QLineEdit(GRAPHQL_URI)
+        # Only allow the default portal URI because invalid ones will cause
+        # indefinite hangs:
+        # https://github.com/chanzuckerberg/cryoet-data-portal/issues/16
+        self._uri_edit.setReadOnly(True)
         self._uri_edit.setCursorPosition(0)
         self._uri_edit.setPlaceholderText("Enter a URI to CryoET portal data")
-        choose_dir_icon = self.style().standardIcon(
-            QStyle.StandardPixmap.SP_DirOpenIcon
-        )
-        self._choose_dir_button = QPushButton(choose_dir_icon, "")
         self._progress: ProgressWidget = ProgressWidget(
-            work=self._checkUri,
-            returnCallback=self._onUriChecked,
+            work=self._connect,
+            returnCallback=self._onConnected,
         )
         self._updateVisibility(False)
 
         self._connect_button.clicked.connect(self._onConnectClicked)
         self._disconnect_button.clicked.connect(self._onDisconnectClicked)
-        self._choose_dir_button.clicked.connect(self._onChooseDirClicked)
         self._uri_edit.returnPressed.connect(self._onConnectClicked)
 
         control_layout = QHBoxLayout()
@@ -55,7 +53,6 @@ def __init__(self, parent: Optional[QWidget] = None) -> None:
         control_layout.addWidget(self._connect_button)
         control_layout.addWidget(self._disconnect_button)
         control_layout.addWidget(self._uri_edit)
-        control_layout.addWidget(self._choose_dir_button)
 
         layout = QVBoxLayout()
         layout.addLayout(control_layout)
@@ -74,27 +71,16 @@ def _onDisconnectClicked(self) -> None:
         self._updateVisibility(False)
         self.disconnected.emit()
 
-    def _checkUri(self, uri: str) -> Tuple[bool, str]:
-        logger.debug("UriWidget._checkUri: %s", uri)
-        return path_exists(uri), uri
+    def _connect(self, uri: str) -> str:
+        _ = Client(uri)
+        return uri
 
-    def _onUriChecked(self, result: Tuple[bool, str]) -> None:
-        logger.debug("UriWidget._onUriChecked: %s", result)
-        exists, uri = result
-        self._updateVisibility(exists)
-        if exists:
-            self.connected.emit(uri)
-        else:
-            raise ValueError(f"CryoET data portal not found at: {uri}")
+    def _onConnected(self, uri: str) -> None:
+        logger.debug("UriWidget._onConnected: %s", uri)
+        self._updateVisibility(True)
+        self.connected.emit(uri)
 
     def _updateVisibility(self, uri_exists: bool) -> None:
         logger.debug("UriWidget._updateVisibility: %s", uri_exists)
         self._connect_button.setVisible(not uri_exists)
-        self._choose_dir_button.setVisible(not uri_exists)
         self._disconnect_button.setVisible(uri_exists)
-        self._uri_edit.setReadOnly(uri_exists)
-
-    def _onChooseDirClicked(self) -> None:
-        logger.debug("DataPathWidget._onChooseDirClicked")
-        path = QFileDialog.getExistingDirectory(self)
-        self._uri_edit.setText(path)
diff --git a/src/napari_cryoet_data_portal/_widget.py b/src/napari_cryoet_data_portal/_widget.py
index 1e65c18..00c98f9 100644
--- a/src/napari_cryoet_data_portal/_widget.py
+++ b/src/napari_cryoet_data_portal/_widget.py
@@ -6,11 +6,11 @@
     QVBoxLayout,
     QWidget,
 )
+from cryoet_data_portal import Client, Tomogram
 
 from napari_cryoet_data_portal._listing_widget import ListingWidget
 from napari_cryoet_data_portal._logging import logger
 from napari_cryoet_data_portal._metadata_widget import MetadataWidget
-from napari_cryoet_data_portal._model import Tomogram
 from napari_cryoet_data_portal._open_widget import OpenWidget
 from napari_cryoet_data_portal._uri_widget import UriWidget
 
@@ -67,6 +67,7 @@ def __init__(
 
     def _onUriConnected(self, uri: str) -> None:
         logger.debug("DataPortalWidget._onUriConnected")
+        self._open.setUri(uri)
         self._listing.load(uri)
 
     def _onUriDisconnected(self) -> None:
diff --git a/src/napari_cryoet_data_portal/napari.yaml b/src/napari_cryoet_data_portal/napari.yaml
index bc0de2b..4bbb584 100644
--- a/src/napari_cryoet_data_portal/napari.yaml
+++ b/src/napari_cryoet_data_portal/napari.yaml
@@ -24,7 +24,7 @@ contributions:
       accepts_directories: true
     - command: napari-cryoet-data-portal.points_annotations_reader
       filename_patterns:
-        - '*.json'
+        - '*.ndjson'
       accepts_directories: false
   sample_data:
     - key: tomogram-10000-ts-026