diff --git a/cubedash/_stac.py b/cubedash/_stac.py
index 6b46bb454..d9d1de845 100644
--- a/cubedash/_stac.py
+++ b/cubedash/_stac.py
@@ -15,6 +15,8 @@
 from eodatasets3.properties import Eo3Dict
 from eodatasets3.utils import is_doc_eo3
 from flask import abort, request
+from pygeofilter.backends.cql2_json import to_cql2
+from pygeofilter.parsers.cql2_text import parse as parse_cql2_text
 from pystac import Catalog, Collection, Extent, ItemCollection, Link, STACObject
 from shapely.geometry import shape
 from shapely.geometry.base import BaseGeometry
@@ -45,7 +47,7 @@
 
 STAC_VERSION = "1.0.0"
 
-ItemLike = pystac.Item | dict
+ItemLike = Union[pystac.Item, dict]
 
 ############################
 #  Helpers
@@ -398,7 +400,7 @@ def _geojson_arg(arg: dict) -> BaseGeometry:
         raise BadRequest("The 'intersects' argument must be valid GeoJSON geometry.")
 
 
-def _bool_argument(s: str | bool):
+def _bool_argument(s: Union[str, bool]):
     """
     Parse an argument that should be a bool
     """
@@ -409,7 +411,7 @@ def _bool_argument(s: str | bool):
     return s.strip().lower() in ("1", "true", "on", "yes")
 
 
-def _dict_arg(arg: str | dict):
+def _dict_arg(arg: Union[str, dict]):
     """
     Parse stac extension arguments as dicts
     """
@@ -418,7 +420,7 @@ def _dict_arg(arg: str | dict):
     return arg
 
 
-def _field_arg(arg: str | list | dict):
+def _field_arg(arg: Union[str, list, dict]):
     """
     Parse field argument into a dict
     """
@@ -440,7 +442,7 @@ def _field_arg(arg: str | list | dict):
         return {"include": include, "exclude": exclude}
 
 
-def _sort_arg(arg: str | list):
+def _sort_arg(arg: Union[str, list]):
     """
     Parse sortby argument into a list of dicts
     """
@@ -452,6 +454,8 @@ def _format(val: str) -> dict[str, str]:
             return {"field": val[1:], "direction": "asc"}
         return {"field": val.strip(), "direction": "asc"}
 
+    if isinstance(arg, str):
+        arg = arg.split(",")
     if len(arg):
         if isinstance(arg[0], str):
             return [_format(a) for a in arg]
@@ -461,6 +465,19 @@ def _format(val: str) -> dict[str, str]:
     return arg
 
 
+def _filter_arg(arg: Union[str, dict]):
+    # if dict, assume cql2-json and return as-is
+    # or do we need to use parse_cql2_json as well?
+    if isinstance(arg, dict):
+        return arg
+    # if json string, convert to dict
+    try:
+        return json.loads(arg)
+    except ValueError:
+        # else assume cql2-text and convert to json format
+        return json.loads(to_cql2(parse_cql2_text(arg)))
+
+
 # Search
 
 
@@ -496,7 +513,8 @@ def _handle_search_request(
 
     sortby = request_args.get("sortby", default=None, type=_sort_arg)
 
-    filter_cql = request_args.get("filter", default=None, type=_dict_arg)
+    filter_cql = request_args.get("filter", default=None, type=_filter_arg)
+    # do we really need to return filter_lang? Or can we convert everything to cql-json
 
     if limit > PAGE_SIZE_LIMIT:
         abort(
@@ -521,6 +539,7 @@ def next_page_url(next_offset):
             limit=limit,
             _o=next_offset,
             _full=full_information,
+            intersects=intersects,
             query=query,
             fields=fields,
             sortby=sortby,
diff --git a/integration_tests/test_stac.py b/integration_tests/test_stac.py
index 52317b5c8..bbd95c0b7 100644
--- a/integration_tests/test_stac.py
+++ b/integration_tests/test_stac.py
@@ -1305,6 +1305,7 @@ def test_stac_fields_extension(stac_client: FlaskClient):
         "properties",
         "stac_version",
         "stac_extensions",
+        "collection",
     } == keys
     properties = doc["features"][0]["properties"]
     assert {"datetime", "dea:dataset_maturity"} == set(properties.keys())
diff --git a/setup.py b/setup.py
index 635409bae..34b7db56a 100755
--- a/setup.py
+++ b/setup.py
@@ -93,6 +93,7 @@
         "sqlalchemy>=1.4",
         "structlog>=20.2.0",
         "pytz",
+        "pygeofilter",
     ],
     tests_require=tests_require,
     extras_require=extras_require,