diff --git a/app/stac_api/pagination.py b/app/stac_api/pagination.py
index 84be48be..8a7fe0d1 100644
--- a/app/stac_api/pagination.py
+++ b/app/stac_api/pagination.py
@@ -171,7 +171,25 @@ def get_page_size(self, request):
         )
 
 
-class GetPostCursorPagination(CursorPagination):
+class SortedCursorPagination(CursorPagination):
+    '''Pagination class that supports sorting via the sortby parameter'''
+    ordering = 'name'
+
+    def get_ordering(self, request, queryset, view):
+        '''Get the ordering from the sortby query parameter if present.'''
+        sort_fields = getattr(view, 'sort_fields', None)
+        if not sort_fields:
+            return super().get_ordering(request, queryset, view)
+
+        ordering = []
+        for model_field, is_ascending in sort_fields:
+            if not is_ascending:
+                model_field = "-" + model_field
+            ordering.append(model_field)
+        return ordering
+
+
+class GetPostCursorPagination(SortedCursorPagination):
     '''Pagination to be used for the GET/POST /search endpoint where the
     pagination is either in query or in payload depending on the method.
     '''
diff --git a/app/stac_api/utils.py b/app/stac_api/utils.py
index 718a2451..d1a3588e 100644
--- a/app/stac_api/utils.py
+++ b/app/stac_api/utils.py
@@ -20,6 +20,7 @@
 from django.conf import settings
 from django.contrib.gis.geos import Point
 from django.contrib.gis.geos import Polygon
+from django.core.exceptions import ValidationError
 from django.core.management import call_command
 from django.core.management.base import BaseCommand
 from django.core.management.base import CommandParser
@@ -629,3 +630,125 @@ def parse_cache_control_header(cache_control_header):
     parts = [i.strip() for i in cache_control_header.split(',')]
     args = {i.split('=')[0].strip(): i.split('=')[-1].strip() for i in parts if i}
     return {k: True if v == k else v for k, v in args.items()}
+
+
+# Maps sortby parameter values to Django model field
+SORTABLE_FIELDS = {
+    'id': 'name',
+    'collection': 'collection__name',
+    'datetime': 'properties_datetime',
+    'title': 'properties_title',
+    'created': 'created',
+    'updated': 'updated',
+}
+
+
+def parse_sortby_get(sortby_param, sortable_fields):
+    '''Parse and validate the GET (string) format of the sortby parameter.
+
+    The sortby parameter is a comma-separated string of fields prefixed with '+'
+    (ascending, default) or '-' (descending).
+
+    Example: "-created,title".
+
+    Args:
+        sortby_param: string
+            Comma-separated list of fields prefixed with '+' or '-'
+        sortable_fields: dict
+            Mapping of allowed sortby field names to Django model fields
+
+    Returns:
+        list: List of tuples (field, direction) where `direction` is True for ascending,
+              False for descending and `field` is the Django model field corresponding to
+              the given input field. Returns empty list if sortby_param is None or empty.
+
+    Raises:
+        ValidationError: If an invalid field is specified
+    '''
+    if not sortby_param:
+        return []
+
+    sort_fields = []
+    for sort_field in sortby_param.split(','):
+        sort_field = sort_field.strip()
+        if not sort_field:
+            continue
+
+        if sort_field.startswith('-'):
+            is_ascending = False
+            field_name = sort_field[1:]
+        elif sort_field.startswith('+'):
+            is_ascending = True
+            field_name = sort_field[1:]
+        else:
+            is_ascending = True
+            field_name = sort_field
+
+        internal_field = _resolve_sort_field(field_name, sortable_fields)
+        sort_fields.append((internal_field, is_ascending))
+    return sort_fields
+
+
+def parse_sortby_post(sortby_param, sortable_fields):
+    '''Parse the POST (list of objects) format of the sortby parameter.
+
+    The sortby parameter in the request body is a list of objects with a 'field'
+    and a 'direction' ('asc' or 'desc') property.
+
+    Example: [{"field": "created", "direction": "desc"}].
+
+    Args:
+        sortby_param: list
+            List of {"field": ..., "direction": ...} objects
+        sortable_fields: dict
+            Mapping of allowed sortby field names to Django model fields
+
+    Returns:
+        list: List of tuples (field, direction) where `direction` is True for ascending,
+              False for descending and `field` is the Django model field corresponding to
+              the given input field. Returns empty list if sortby_param is None or empty.
+
+    Raises:
+        ValidationError: If an invalid field or direction is specified
+    '''
+    sort_fields = []
+    for sort_item in sortby_param:
+        if not isinstance(sort_item, dict) or 'field' not in sort_item:
+            raise ValidationError("Each sortby entry must be an object with a 'field' property")
+        field_name = sort_item['field']
+        direction = str(sort_item.get('direction', 'asc')).lower()
+        if direction == 'asc':
+            is_ascending = True
+        elif direction == 'desc':
+            is_ascending = False
+        else:
+            raise ValidationError(
+                f"Invalid sort direction '{direction}'. "
+                f"Allowed values are: 'asc', 'desc'"
+            )
+        internal_field = _resolve_sort_field(field_name, sortable_fields)
+        sort_fields.append((internal_field, is_ascending))
+    return sort_fields
+
+
+def _resolve_sort_field(field_name, sortable_fields):
+    '''Resolve a sortby field name to its Django model field, validating it.
+
+    Args:
+        field_name: string
+            The field name provided in the sortby parameter
+        sortable_fields: dict
+            Mapping of allowed sortby field names to Django model fields
+
+    Returns:
+        string: The Django model field corresponding to the given field name
+
+    Raises:
+        ValidationError: If the field name is not allowed for sorting
+    '''
+    if field_name not in sortable_fields:
+        raise ValidationError(
+            f"Invalid sort field '{field_name}'. "
+            f"Allowed fields are: {', '.join(sortable_fields.keys())}"
+        )
+    return sortable_fields[field_name]
diff --git a/app/stac_api/validators_serializer.py b/app/stac_api/validators_serializer.py
index 67688f61..0d045829 100644
--- a/app/stac_api/validators_serializer.py
+++ b/app/stac_api/validators_serializer.py
@@ -3,15 +3,19 @@
 
 from django.contrib.gis.gdal.error import GDALException
 from django.contrib.gis.geos import GEOSGeometry
+from django.core.exceptions import ValidationError as DjangoValidationError
 from django.db import IntegrityError
 from django.db import transaction
 from django.utils.translation import gettext_lazy as _
 
 from rest_framework import serializers
 
+from stac_api.utils import SORTABLE_FIELDS
 from stac_api.utils import fromisoformat
 from stac_api.utils import geometry_from_bbox
 from stac_api.utils import harmonize_post_get_for_search
+from stac_api.utils import parse_sortby_get
+from stac_api.utils import parse_sortby_post
 from stac_api.validators import validate_geometry
 
 logger = logging.getLogger(__name__)
@@ -72,7 +76,7 @@ def __init__(self):
         self.queriable_date_fields = ['created', 'updated']
         self.queriable_str_fields = ['title', 'cf:standard_name', 'unit']
 
-    def validate(self, request):
+    def validate(self, request):  # pylint: disable=too-many-branches
         '''Validates the request of the search endpoint
 
         This function validates the request of the search endpoint. As a simplification the
@@ -93,6 +97,15 @@ def validate(self, request):
         if request.method == "POST":
             self.validate_query_parameters_post_search(query_param)
 
+        try:
+            if 'sortby' in query_param:
+                if request.method == "POST":
+                    request.sort_fields = parse_sortby_post(query_param['sortby'], SORTABLE_FIELDS)
+                else:
+                    request.sort_fields = parse_sortby_get(query_param['sortby'], SORTABLE_FIELDS)
+        except DjangoValidationError as error:
+            self.errors['sortby'] = _(error.message)
+
         if 'bbox' in query_param:
             self.validate_bbox(query_param['bbox'])
         if 'datetime' in query_param:
@@ -366,6 +379,7 @@ def validate_query_parameters_post_search(self, query_param):
             "limit",
             "cursor",
             "query",
+            "sortby",
             "forecast:reference_datetime",
             "forecast:horizon",
             "forecast:duration",
diff --git a/app/stac_api/views/general.py b/app/stac_api/views/general.py
index 84a30700..e0944163 100644
--- a/app/stac_api/views/general.py
+++ b/app/stac_api/views/general.py
@@ -69,6 +69,8 @@ class SearchList(generics.GenericAPIView, mixins.ListModelMixin):
     # search overall collections and that the item name is only unique within a collection
     # we must use the pk as ordering attribute, otherwise the cursor pagination will not work
     ordering = ['pk']
+    # Resolved sortby fields. None means no sortby was provided and the default ordering is used.
+    sort_fields = None
 
     # pylint: disable=too-many-branches
     def get_queryset(self):
@@ -121,6 +123,7 @@ def list(self, request, *args, **kwargs):
 
         validate_search_request = ValidateSearchRequest()
         validate_search_request.validate(request)  # validate the search request
+        self.sort_fields = getattr(request, 'sort_fields', None)
         queryset = self.filter_queryset(self.get_queryset())
 
         page = self.paginate_queryset(queryset)
diff --git a/app/stac_api/views/item.py b/app/stac_api/views/item.py
index 6d0f8cc9..7d2f6a5f 100644
--- a/app/stac_api/views/item.py
+++ b/app/stac_api/views/item.py
@@ -18,12 +18,15 @@
 from stac_api.models.collection import Collection
 from stac_api.models.item import Asset
 from stac_api.models.item import Item
+from stac_api.pagination import SortedCursorPagination
 from stac_api.serializers.item import AssetSerializer
 from stac_api.serializers.item import ItemDetailSerializer
 from stac_api.serializers.item import ItemListSerializer
 from stac_api.serializers.item import ItemSerializer
 from stac_api.serializers.utils import get_relation_links
+from stac_api.utils import SORTABLE_FIELDS
 from stac_api.utils import get_asset_path
+from stac_api.utils import parse_sortby_get
 from stac_api.validators_view import validate_collection
 from stac_api.validators_view import validate_item
 from stac_api.validators_view import validate_renaming
@@ -89,8 +92,10 @@ def get_asset_etag(request, *args, **kwargs):
 
 class ItemsList(generics.GenericAPIView):
     serializer_class = ItemSerializer
-    ordering = ['name']
+    pagination_class = SortedCursorPagination
     name = 'items-list'  # this name must match the name in urls.py
+    # Resolved sortby fields. None means no sortby was provided and the default ordering is used.
+    sort_fields = None
 
     def get_queryset(self):
         # filter based on the url
@@ -122,6 +127,11 @@ def get_queryset(self):
 
     def list(self, request, *args, **kwargs):
         validate_collection(self.kwargs)
+
+        sort_fields = request.query_params.get('sortby')
+        if sort_fields:
+            self.sort_fields = parse_sortby_get(sort_fields, SORTABLE_FIELDS)
+
         queryset = self.filter_queryset(self.get_queryset())
         page = self.paginate_queryset(queryset)
         if page is not None:
diff --git a/app/tests/tests_10/test_items_endpoint.py b/app/tests/tests_10/test_items_endpoint.py
index c24b4f46..594f54e5 100644
--- a/app/tests/tests_10/test_items_endpoint.py
+++ b/app/tests/tests_10/test_items_endpoint.py
@@ -188,6 +188,102 @@ def test_items_endpoint_non_existing_collection(self):
         response = self.client.get(f"/{STAC_BASE_V}/collections/non-existing-collection/items")
         self.assertStatusCode(404, response)
 
+    def test_sortby_id_ascending(self):
+        response = self.client.get(
+            f"/{STAC_BASE_V}/collections/{self.collection.name}/items?sortby=id"
+        )
+
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ["item-1", "item-2"])
+
+    def test_sortby_id_descending(self):
+        response = self.client.get(
+            f"/{STAC_BASE_V}/collections/{self.collection.name}/items?sortby=-id"
+        )
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ["item-2", "item-1"])
+
+    def test_sortby_properties_datetime(self):
+
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-1',
+            properties_datetime=timezone.now() + timedelta(days=2),
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-2',
+            properties_datetime=timezone.now() + timedelta(days=1),
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-3',
+            properties_datetime=timezone.now() + timedelta(days=3),
+            db_create=True
+        )
+
+        # Test ascending sort
+        response = self.client.get(
+            f"/{STAC_BASE_V}/collections/{self.collection.name}/items?sortby=datetime"
+        )
+
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ['item-1', 'item-2', 'item-dt-2', 'item-dt-1', 'item-dt-3'])
+
+        # Test descending sort
+        response = self.client.get(
+            f"/{STAC_BASE_V}/collections/{self.collection.name}/items?sortby=-datetime"
+        )
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ['item-dt-3', 'item-dt-1', 'item-dt-2', 'item-1', 'item-2'])
+
+    def test_sortby_multiple_fields(self):
+        tomorrow = timezone.now() + timedelta(days=1)
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-1',
+            properties_datetime=tomorrow,
+            properties_title='AAA',
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-2',
+            properties_datetime=tomorrow,
+            properties_title='BBB',
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-3',
+            properties_datetime=tomorrow + timedelta(days=1),
+            properties_title='CCC',
+            db_create=True
+        )
+
+        # Sort by datetime ascending, then by title descending
+        response = self.client.get(
+            (f"/{STAC_BASE_V}/collections/{self.collection.name}/items?"
+             f"sortby=datetime,-title")
+        )
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(
+            item_ids, ['item-1', 'item-2', 'item-multi-2', 'item-multi-1', 'item-multi-3']
+        )
+
+    def test_sortby_invalid_field(self):
+        response = self.client.get(
+            f"/{STAC_BASE_V}/collections/{self.collection.name}/items?sortby=expires"
+        )
+        self.assertStatusCode(400, response)
+
 
 class ItemsDatetimeQueryEndpointTestCase(StacBaseTestCase):
 
diff --git a/app/tests/tests_10/test_search_endpoint.py b/app/tests/tests_10/test_search_endpoint.py
index f50e80b4..4c8f21dc 100644
--- a/app/tests/tests_10/test_search_endpoint.py
+++ b/app/tests/tests_10/test_search_endpoint.py
@@ -3,9 +3,7 @@
 from datetime import UTC
 from datetime import datetime
 from datetime import timedelta
-from unittest import skip
 from unittest.mock import patch
-from urllib.parse import quote_plus
 
 from django.test import Client
 from django.test import override_settings
@@ -616,211 +614,3 @@ def test_post_search_no_cache_setting(self):
             response.has_header('Cache-Control'),
             msg="Unexpected Cache-Control header in POST response"
         )
-
-
-class SearchEndpointTestForecast(StacBaseTestCase):
-
-    @classmethod
-    def setUpTestData(cls):
-        cls.factory = Factory()
-        cls.collection = cls.factory.create_collection_sample().model
-        cls.factory.create_item_sample(
-            cls.collection, 'item-forecast-1', 'item-forecast-1', db_create=True
-        )
-        cls.factory.create_item_sample(
-            cls.collection, 'item-forecast-2', 'item-forecast-2', db_create=True
-        )
-        cls.factory.create_item_sample(
-            cls.collection, 'item-forecast-3', 'item-forecast-3', db_create=True
-        )
-        cls.factory.create_item_sample(
-            cls.collection, 'item-forecast-4', 'item-forecast-4', db_create=True
-        )
-        cls.factory.create_item_sample(
-            cls.collection, 'item-forecast-5', 'item-forecast-5', db_create=True
-        )
-        cls.now = datetime.now(UTC)
-        cls.yesterday = cls.now - timedelta(days=1)
-
-    def setUp(self):  # pylint: disable=invalid-name
-        self.client = Client()
-        self.path = f'/{STAC_BASE_V}/search'
-        self.maxDiff = None  # pylint: disable=invalid-name
-
-    def test_reference_datetime_exact(self):
-        payload = {"forecast:reference_datetime": "2025-01-01T13:05:10Z"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 1)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-forecast-1'])
-
-        payload = {"forecast:reference_datetime": "2025-02-01T13:05:10Z"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 3)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-forecast-2', 'item-forecast-3', 'item-forecast-4'])
-
-    def test_reference_datetime_range(self):
-        payload = {"forecast:reference_datetime": "2025-02-01T00:00:00Z/2025-02-28T00:00:00Z"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 3)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-forecast-2', 'item-forecast-3', 'item-forecast-4'])
-
-    def test_reference_datetime_open_end(self):
-        payload = {"forecast:reference_datetime": "2025-02-01T13:05:10Z/.."}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 4)
-        for feature in json_data['features']:
-            self.assertIn(
-                feature['id'],
-                ['item-forecast-2', 'item-forecast-3', 'item-forecast-4', 'item-forecast-5']
-            )
-
-    def test_reference_datetime_open_start(self):
-        payload = {"forecast:reference_datetime": "../2025-02-01T13:05:10Z"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 4)
-        for feature in json_data['features']:
-            self.assertIn(
-                feature['id'],
-                ['item-forecast-1', 'item-forecast-2', 'item-forecast-3', 'item-forecast-4']
-            )
-
-    def test_horizon(self):
-        payload = {"forecast:horizon": "PT3H"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 1)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-forecast-3'])
-
-    def test_duration(self):
-        payload = {"forecast:duration": "PT12H"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 4)
-        for feature in json_data['features']:
-            self.assertIn(
-                feature['id'],
-                ['item-forecast-1', 'item-forecast-2', 'item-forecast-4', 'item-forecast-5']
-            )
-
-    def test_variable(self):
-        payload = {"forecast:variable": "air_temperature"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 2)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-forecast-4', 'item-forecast-5'])
-
-    def test_perturbed(self):
-        payload = {"forecast:perturbed": "True"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 1)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-forecast-4'])
-
-    def test_multiple(self):
-        payload = {
-            "forecast:perturbed": "False", "forecast:horizon": "PT6H", "forecast:variable": "T"
-        }
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 2)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-forecast-1', 'item-forecast-2'])
-
-    def test_get_request_does_not_filter_forecast(self):
-        response = self.client.get(
-            f"{self.path}?" + quote_plus(
-                "forecast:reference_datetime=2025-01-01T13:05:10Z&" + "forecast:duration=PT12H&" +
-                "forecast:perturbed=False&" + "forecast:horizon=PT6H&" + "forecast:variable=T"
-            )
-        )
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        # As GET request should not filter for forecast expect all 5 features to be returned.
-        self.assertEqual(len(json_data['features']), 5)
-
-
-class SearchEndpointTestCF(StacBaseTestCase):
-
-    @classmethod
-    def setUpTestData(cls):
-        cls.factory = Factory()
-        cls.collection = cls.factory.create_collection_sample().model
-        cls.factory.create_item_sample(cls.collection, 'item-cf-1', 'item-cf-1', db_create=True)
-        cls.factory.create_item_sample(cls.collection, 'item-cf-2', 'item-cf-2', db_create=True)
-        cls.factory.create_item_sample(cls.collection, 'item-cf-3', 'item-cf-3', db_create=True)
-
-    def setUp(self):  # pylint: disable=invalid-name
-        self.client = Client()
-        self.path = f'/{STAC_BASE_V}/search'
-        self.maxDiff = None  # pylint: disable=invalid-name
-
-    def test_cf_standard_name(self):
-        payload = {"query": {"cf:standard_name": {"eq": "air_temperature"}}}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 2)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-cf-1', 'item-cf-2'])
-
-    def test_unit(self):
-        payload = {"query": {"unit": {"eq": "K"}}}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 1)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-cf-1'])
-
-    @skip(
-        "PB-2354: Known bug - Cannot filter by multiple fields. "
-        "Will be fixed by implementing Filter Extension instead."
-    )
-    def test_multiple_cf(self):
-        payload = {"query": {"cf:standard_name": {"eq": "air_temperature"}, "unit": {"eq": "K"}}}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        self.assertEqual(len(json_data['features']), 1)
-        for feature in json_data['features']:
-            self.assertIn(feature['id'], ['item-cf-1'])
-
-    def test_cf_standard_name_invalid_as_direct_param(self):
-        payload = {"cf:standard_name": "air_temperature"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(400, response)
-
-    def test_unit_invalid_as_direct_param(self):
-        payload = {"unit": "K"}
-        response = self.client.post(self.path, data=payload, content_type="application/json")
-        self.assertStatusCode(400, response)
-
-    def test_get_request_does_not_filter_cf(self):
-        response = self.client.get(
-            f"{self.path}?" + quote_plus("cf:standard_name=air_temperature&" + "unit=K")
-        )
-        self.assertStatusCode(200, response)
-        json_data = response.json()
-        # As GET request should not filter for CF expect all 3 features to be returned.
-        self.assertEqual(len(json_data['features']), 3)
diff --git a/app/tests/tests_10/test_search_endpoint_extensions.py b/app/tests/tests_10/test_search_endpoint_extensions.py
new file mode 100644
index 00000000..19f5323a
--- /dev/null
+++ b/app/tests/tests_10/test_search_endpoint_extensions.py
@@ -0,0 +1,441 @@
+import logging
+from datetime import UTC
+from datetime import datetime
+from datetime import timedelta
+from unittest import skip
+from urllib.parse import quote_plus
+
+from django.test import Client
+from django.utils import timezone
+
+from stac_api.utils import fromisoformat
+
+from tests.tests_10.base_test import STAC_BASE_V
+from tests.tests_10.base_test import StacBaseTestCase
+from tests.tests_10.data_factory import Factory
+
+logger = logging.getLogger(__name__)
+
+
+class SearchEndpointTestForecast(StacBaseTestCase):
+
+    @classmethod
+    def setUpTestData(cls):
+        cls.factory = Factory()
+        cls.collection = cls.factory.create_collection_sample().model
+        cls.factory.create_item_sample(
+            cls.collection, 'item-forecast-1', 'item-forecast-1', db_create=True
+        )
+        cls.factory.create_item_sample(
+            cls.collection, 'item-forecast-2', 'item-forecast-2', db_create=True
+        )
+        cls.factory.create_item_sample(
+            cls.collection, 'item-forecast-3', 'item-forecast-3', db_create=True
+        )
+        cls.factory.create_item_sample(
+            cls.collection, 'item-forecast-4', 'item-forecast-4', db_create=True
+        )
+        cls.factory.create_item_sample(
+            cls.collection, 'item-forecast-5', 'item-forecast-5', db_create=True
+        )
+        cls.now = datetime.now(UTC)
+        cls.yesterday = cls.now - timedelta(days=1)
+
+    def setUp(self):  # pylint: disable=invalid-name
+        self.client = Client()
+        self.path = f'/{STAC_BASE_V}/search'
+        self.maxDiff = None  # pylint: disable=invalid-name
+
+    def test_reference_datetime_exact(self):
+        payload = {"forecast:reference_datetime": "2025-01-01T13:05:10Z"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 1)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-forecast-1'])
+
+        payload = {"forecast:reference_datetime": "2025-02-01T13:05:10Z"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 3)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-forecast-2', 'item-forecast-3', 'item-forecast-4'])
+
+    def test_reference_datetime_range(self):
+        payload = {"forecast:reference_datetime": "2025-02-01T00:00:00Z/2025-02-28T00:00:00Z"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 3)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-forecast-2', 'item-forecast-3', 'item-forecast-4'])
+
+    def test_reference_datetime_open_end(self):
+        payload = {"forecast:reference_datetime": "2025-02-01T13:05:10Z/.."}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 4)
+        for feature in json_data['features']:
+            self.assertIn(
+                feature['id'],
+                ['item-forecast-2', 'item-forecast-3', 'item-forecast-4', 'item-forecast-5']
+            )
+
+    def test_reference_datetime_open_start(self):
+        payload = {"forecast:reference_datetime": "../2025-02-01T13:05:10Z"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 4)
+        for feature in json_data['features']:
+            self.assertIn(
+                feature['id'],
+                ['item-forecast-1', 'item-forecast-2', 'item-forecast-3', 'item-forecast-4']
+            )
+
+    def test_horizon(self):
+        payload = {"forecast:horizon": "PT3H"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 1)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-forecast-3'])
+
+    def test_duration(self):
+        payload = {"forecast:duration": "PT12H"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 4)
+        for feature in json_data['features']:
+            self.assertIn(
+                feature['id'],
+                ['item-forecast-1', 'item-forecast-2', 'item-forecast-4', 'item-forecast-5']
+            )
+
+    def test_variable(self):
+        payload = {"forecast:variable": "air_temperature"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 2)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-forecast-4', 'item-forecast-5'])
+
+    def test_perturbed(self):
+        payload = {"forecast:perturbed": "True"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 1)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-forecast-4'])
+
+    def test_multiple(self):
+        payload = {
+            "forecast:perturbed": "False", "forecast:horizon": "PT6H", "forecast:variable": "T"
+        }
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 2)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-forecast-1', 'item-forecast-2'])
+
+    def test_get_request_does_not_filter_forecast(self):
+        response = self.client.get(
+            f"{self.path}?" + quote_plus(
+                "forecast:reference_datetime=2025-01-01T13:05:10Z&" + "forecast:duration=PT12H&" +
+                "forecast:perturbed=False&" + "forecast:horizon=PT6H&" + "forecast:variable=T"
+            )
+        )
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        # As GET request should not filter for forecast expect all 5 features to be returned.
+        self.assertEqual(len(json_data['features']), 5)
+
+
+class SearchEndpointTestCF(StacBaseTestCase):
+
+    @classmethod
+    def setUpTestData(cls):
+        cls.factory = Factory()
+        cls.collection = cls.factory.create_collection_sample().model
+        cls.factory.create_item_sample(cls.collection, 'item-cf-1', 'item-cf-1', db_create=True)
+        cls.factory.create_item_sample(cls.collection, 'item-cf-2', 'item-cf-2', db_create=True)
+        cls.factory.create_item_sample(cls.collection, 'item-cf-3', 'item-cf-3', db_create=True)
+
+    def setUp(self):  # pylint: disable=invalid-name
+        self.client = Client()
+        self.path = f'/{STAC_BASE_V}/search'
+        self.maxDiff = None  # pylint: disable=invalid-name
+
+    def test_cf_standard_name(self):
+        payload = {"query": {"cf:standard_name": {"eq": "air_temperature"}}}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 2)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-cf-1', 'item-cf-2'])
+
+    def test_unit(self):
+        payload = {"query": {"unit": {"eq": "K"}}}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 1)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-cf-1'])
+
+    @skip(
+        "PB-2354: Known bug - Cannot filter by multiple fields. "
+        "Will be fixed by implementing Filter Extension instead."
+    )
+    def test_multiple_cf(self):
+        payload = {"query": {"cf:standard_name": {"eq": "air_temperature"}, "unit": {"eq": "K"}}}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        self.assertEqual(len(json_data['features']), 1)
+        for feature in json_data['features']:
+            self.assertIn(feature['id'], ['item-cf-1'])
+
+    def test_cf_standard_name_invalid_as_direct_param(self):
+        payload = {"cf:standard_name": "air_temperature"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(400, response)
+
+    def test_unit_invalid_as_direct_param(self):
+        payload = {"unit": "K"}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(400, response)
+
+    def test_get_request_does_not_filter_cf(self):
+        response = self.client.get(
+            f"{self.path}?" + quote_plus("cf:standard_name=air_temperature&" + "unit=K")
+        )
+        self.assertStatusCode(200, response)
+        json_data = response.json()
+        # As GET request should not filter for CF expect all 3 features to be returned.
+        self.assertEqual(len(json_data['features']), 3)
+
+
+class SearchEndpointSortTestCase(StacBaseTestCase):
+    '''Tests for the sortby parameter on the GET and POST /search endpoint'''
+
+    @classmethod
+    def setUpTestData(cls):
+        cls.factory = Factory()
+        cls.collection = cls.factory.create_collection_sample().model
+        # Give item-1 and item-2 distinct datetimes so that sorting by
+        # properties.datetime is fully deterministic (no tie-breaking).
+        cls.items = [
+            cls.factory.create_item_sample(
+                cls.collection,
+                name='item-1',
+                sample='item-1',
+                properties_datetime=fromisoformat('2020-10-28T13:05:10Z'),
+                db_create=True
+            ),
+            cls.factory.create_item_sample(
+                cls.collection,
+                name='item-2',
+                sample='item-1',
+                properties_datetime=fromisoformat('2020-10-29T13:05:10Z'),
+                db_create=True
+            )
+        ]
+
+    def setUp(self):  # pylint: disable=invalid-name
+        self.client = Client()
+        self.path = f'/{STAC_BASE_V}/search'
+        self.maxDiff = None  # pylint: disable=invalid-name
+
+    def test_get_sortby_id_ascending(self):
+        response = self.client.get(f"{self.path}?sortby=id")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ["item-1", "item-2"])
+
+    def test_get_sortby_id_descending(self):
+        response = self.client.get(f"{self.path}?sortby=-id")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ["item-2", "item-1"])
+
+    def test_get_sortby_properties_datetime(self):
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-1',
+            properties_datetime=timezone.now() + timedelta(days=2),
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-2',
+            properties_datetime=timezone.now() + timedelta(days=1),
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-3',
+            properties_datetime=timezone.now() + timedelta(days=3),
+            db_create=True
+        )
+
+        # ascending sort
+        response = self.client.get(f"{self.path}?sortby=datetime")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ['item-1', 'item-2', 'item-dt-2', 'item-dt-1', 'item-dt-3'])
+
+        # descending sort
+        response = self.client.get(f"{self.path}?sortby=-datetime")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ['item-dt-3', 'item-dt-1', 'item-dt-2', 'item-2', 'item-1'])
+
+    def test_get_sortby_multiple_fields(self):
+        tomorrow = timezone.now() + timedelta(days=1)
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-1',
+            properties_datetime=tomorrow,
+            properties_title='AAA',
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-2',
+            properties_datetime=tomorrow,
+            properties_title='BBB',
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-3',
+            properties_datetime=tomorrow + timedelta(days=1),
+            properties_title='CCC',
+            db_create=True
+        )
+
+        # Sort by datetime ascending, then by title descending
+        response = self.client.get(f"{self.path}?sortby=datetime,-title")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(
+            item_ids, ['item-1', 'item-2', 'item-multi-2', 'item-multi-1', 'item-multi-3']
+        )
+
+    def test_get_sortby_invalid_field(self):
+        response = self.client.get(f"{self.path}?sortby=expires")
+        self.assertStatusCode(400, response)
+
+    def test_post_sortby_empty_list(self):
+        payload = {"sortby": []}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ["item-1", "item-2"])
+
+    def test_post_sortby_id_ascending(self):
+        payload = {"sortby": [{"field": "id", "direction": "asc"}]}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ["item-1", "item-2"])
+
+    def test_post_sortby_id_descending(self):
+        payload = {"sortby": [{"field": "id", "direction": "desc"}]}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ["item-2", "item-1"])
+
+    def test_post_sortby_properties_datetime(self):
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-1',
+            properties_datetime=timezone.now() + timedelta(days=2),
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-2',
+            properties_datetime=timezone.now() + timedelta(days=1),
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-dt-3',
+            properties_datetime=timezone.now() + timedelta(days=3),
+            db_create=True
+        )
+
+        # ascending sort
+        payload = {"sortby": [{"field": "datetime", "direction": "asc"}]}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ['item-1', 'item-2', 'item-dt-2', 'item-dt-1', 'item-dt-3'])
+
+        # descending sort
+        payload = {"sortby": [{"field": "datetime", "direction": "desc"}]}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(item_ids, ['item-dt-3', 'item-dt-1', 'item-dt-2', 'item-2', 'item-1'])
+
+    def test_post_sortby_multiple_fields(self):
+        tomorrow = timezone.now() + timedelta(days=1)
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-1',
+            properties_datetime=tomorrow,
+            properties_title='AAA',
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-2',
+            properties_datetime=tomorrow,
+            properties_title='BBB',
+            db_create=True
+        )
+        self.factory.create_item_sample(
+            self.collection,
+            name='item-multi-3',
+            properties_datetime=tomorrow + timedelta(days=1),
+            properties_title='CCC',
+            db_create=True
+        )
+
+        # Sort by datetime ascending, then by title descending
+        payload = {
+            "sortby": [{
+                "field": "datetime", "direction": "asc"
+            }, {
+                "field": "title", "direction": "desc"
+            }]
+        }
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(200, response)
+        item_ids = [item['id'] for item in response.json()['features']]
+        self.assertEqual(
+            item_ids, ['item-1', 'item-2', 'item-multi-2', 'item-multi-1', 'item-multi-3']
+        )
+
+    def test_post_sortby_invalid_field(self):
+        payload = {"sortby": [{"field": "expires", "direction": "asc"}]}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(400, response)
+
+    def test_post_sortby_invalid_direction(self):
+        payload = {"sortby": [{"field": "id", "direction": "sideways"}]}
+        response = self.client.post(self.path, data=payload, content_type="application/json")
+        self.assertStatusCode(400, response)
diff --git a/app/tests/tests_10/test_utils.py b/app/tests/tests_10/test_utils.py
index a8fc961b..df151f7b 100644
--- a/app/tests/tests_10/test_utils.py
+++ b/app/tests/tests_10/test_utils.py
@@ -1,6 +1,10 @@
 from unittest import TestCase
 
+from django.core.exceptions import ValidationError
+
 from stac_api.utils import parse_cache_control_header
+from stac_api.utils import parse_sortby_get
+from stac_api.utils import parse_sortby_post
 
 
 class TestUtils(TestCase):
@@ -23,3 +27,113 @@ def test_parse_cache_control_header(self):
         self.assertEqual(parse_cache_control_header(','), {})
         self.assertEqual(parse_cache_control_header('   '), {})
         self.assertEqual(parse_cache_control_header('  ,   '), {})
+
+    def test_parse_sortby_get_empty(self):
+        result = parse_sortby_get(None, {})
+        self.assertEqual(result, [])
+
+        result = parse_sortby_get('', {})
+        self.assertEqual(result, [])
+
+        result = parse_sortby_get('   ', {})
+        self.assertEqual(result, [])
+
+    def test_parse_sortby_get_handles_single_field_correctly(self):
+        sortable_fields = {'external': 'internal'}
+
+        result = parse_sortby_get('external', sortable_fields)
+        self.assertEqual(result, [('internal', True)])
+
+        result = parse_sortby_get('+external', sortable_fields)
+        self.assertEqual(result, [('internal', True)])
+
+        result = parse_sortby_get('-external', sortable_fields)
+        self.assertEqual(result, [('internal', False)])
+
+    def test_parse_sortby_get_handles_multiple_fields_correctly(self):
+        sortable_fields = {
+            'external_1': 'internal_1',
+            'external_2': 'internal_2',
+            'external_3': 'internal_3',
+        }
+
+        result = parse_sortby_get('external_1,-external_2', sortable_fields)
+        self.assertEqual(result, [('internal_1', True), ('internal_2', False)])
+
+        result = parse_sortby_get('-external_1,external_2', sortable_fields)
+        self.assertEqual(result, [('internal_1', False), ('internal_2', True)])
+
+        result = parse_sortby_get('+external_1,-external_2,external_3', sortable_fields)
+        self.assertEqual(
+            result, [('internal_1', True), ('internal_2', False), ('internal_3', True)]
+        )
+
+    def test_parse_sortby_get_ignores_whitespace(self):
+        sortable_fields = {
+            'external_1': 'internal_1',
+            'external_2': 'internal_2',
+        }
+        result = parse_sortby_get('external_1 , -external_2', sortable_fields)
+        self.assertEqual(result, [('internal_1', True), ('internal_2', False)])
+
+    def test_parse_sortby_get_raises_for_invalid_field(self):
+        with self.assertRaises(ValidationError):
+            parse_sortby_get('invalid_field', {'external': 'internal'})
+
+    def test_parse_sortby_post_format_empty(self):
+        result = parse_sortby_post([], {})
+        self.assertEqual(result, [])
+
+    def test_parse_sortby_post_format_handles_single_field_correctly(self):
+        sortable_fields = {'external': 'internal'}
+
+        result = parse_sortby_post([{'field': 'external', 'direction': 'asc'}], sortable_fields)
+        self.assertEqual(result, [('internal', True)])
+
+        result = parse_sortby_post([{'field': 'external', 'direction': 'desc'}], sortable_fields)
+        self.assertEqual(result, [('internal', False)])
+
+        # direction defaults to ascending when omitted
+        result = parse_sortby_post([{'field': 'external'}], sortable_fields)
+        self.assertEqual(result, [('internal', True)])
+
+    def test_parse_sortby_post_format_handles_multiple_fields_correctly(self):
+        sortable_fields = {
+            'external_1': 'internal_1',
+            'external_2': 'internal_2',
+        }
+        sortby_param = [{
+            'field': 'external_1',
+            'direction': 'asc',
+        }, {
+            'field': 'external_2',
+            'direction': 'desc',
+        }]
+        result = parse_sortby_post(sortby_param, sortable_fields)
+        self.assertEqual(result, [('internal_1', True), ('internal_2', False)])
+
+        sortby_param = [{
+            'field': 'external_1',
+            'direction': 'desc',
+        }, {
+            'field': 'external_2',
+            'direction': 'asc',
+        }]
+        result = parse_sortby_post(sortby_param, sortable_fields)
+        self.assertEqual(result, [('internal_1', False), ('internal_2', True)])
+
+    def test_parse_sortby_post_format_raises_for_invalid_field(self):
+        with self.assertRaises(ValidationError):
+            parse_sortby_post([{
+                'field': 'invalid_field', 'direction': 'asc'
+            }], {'external': 'internal'})
+
+    def test_parse_sortby_post_format_raises_for_invalid_direction(self):
+        with self.assertRaises(ValidationError):
+            parse_sortby_post([{
+                'field': 'external', 'direction': 'sideways'
+            }], {'external': 'internal'})
+
+    def test_parse_sortby_post_format_raises_for_missing_field(self):
+        with self.assertRaises(ValidationError):
+            parse_sortby_post([{'direction': 'asc'}], {'external': 'internal'})
diff --git a/spec/components/parameters.yaml b/spec/components/parameters.yaml
index 20495079..4399b62f 100644
--- a/spec/components/parameters.yaml
+++ b/spec/components/parameters.yaml
@@ -132,3 +132,13 @@ components:
       required: false
       schema:
         type: string
+    sortby:
+      name: sortby
+      in: query
+      description: >-
+        An array of property names, prefixed by either "+" for ascending or
+        "-" for descending. If no prefix is provided, "+" is assumed.
+      required: false
+      schema:
+        type: string
+        example: '-created,id'
diff --git a/spec/components/schemas.yaml b/spec/components/schemas.yaml
index a9908953..8c82c09a 100644
--- a/spec/components/schemas.yaml
+++ b/spec/components/schemas.yaml
@@ -1732,6 +1732,34 @@ components:
       description: Purposes of the asset
       example:
         - thumbnail
+    sortby:
+      type: array
+      description: >-
+        An array of objects containing a property name and sort direction.
+      items:
+        type: object
+        required:
+          - field
+        properties:
+          field:
+            type: string
+          direction:
+            type: string
+            default: asc
+            enum:
+              - asc
+              - desc
+      example:
+        - field: created
+          direction: asc
+        - field: collection
+          direction: desc
+    sortbyFilter:
+      description: Sort the results by the specified fields.
+      properties:
+        sortby:
+          $ref: "#/components/schemas/sortby"
+      type: object
     searchBody:
       allOf:
         #        - $ref: "#/components/schemas/assetQueryFilter"
@@ -1742,6 +1770,7 @@ components:
         - $ref: "#/components/schemas/collectionsFilter"
         - $ref: "#/components/schemas/idsFilter"
         - $ref: "#/components/schemas/limitFilter"
+        - $ref: "#/components/schemas/sortbyFilter"
         - $ref: "#/components/schemas/forecast_reference_datetimeFilter"
         - $ref: "#/components/schemas/forecast_horizonFilter"
         - $ref: "#/components/schemas/forecast_durationFilter"
diff --git a/spec/openapi.yaml b/spec/openapi.yaml
index 09e41a35..c5e7e229 100644
--- a/spec/openapi.yaml
+++ b/spec/openapi.yaml
@@ -92,6 +92,7 @@ paths:
         - $ref: "./components/parameters.yaml#/components/parameters/limit"
         - $ref: "./components/parameters.yaml#/components/parameters/bbox"
         - $ref: "./components/parameters.yaml#/components/parameters/datetime"
+        - $ref: "./components/parameters.yaml#/components/parameters/sortby"
       responses:
         "200":
           $ref: "./components/responses.yaml#/components/responses/Features"
@@ -331,6 +332,7 @@ paths:
         - $ref: "./components/parameters.yaml#/components/parameters/limit"
         - $ref: "./components/parameters.yaml#/components/parameters/ids"
         - $ref: "./components/parameters.yaml#/components/parameters/collectionsArray"
+        - $ref: "./components/parameters.yaml#/components/parameters/sortby"
       responses:
         "200":
           content:
diff --git a/spec/static/spec/v1/openapi.yaml b/spec/static/spec/v1/openapi.yaml
index fb376e67..203a3e04 100644
--- a/spec/static/spec/v1/openapi.yaml
+++ b/spec/static/spec/v1/openapi.yaml
@@ -130,6 +130,15 @@ components:
       required: false
       schema:
         type: string
+    sortby:
+      name: sortby
+      in: query
+      description: >-
+        An array of property names, prefixed by either "+" for ascending or "-" for descending. If no prefix is provided, "+" is assumed.
+      required: false
+      schema:
+        type: string
+        example: '-created,id'
   responses:
     Collection:
       headers:
@@ -1954,6 +1963,34 @@ components:
       description: Purposes of the asset
       example:
         - thumbnail
+    sortby:
+      type: array
+      description: >-
+        An array of objects containing a property name and sort direction.
+      items:
+        type: object
+        required:
+          - field
+        properties:
+          field:
+            type: string
+          direction:
+            type: string
+            default: asc
+            enum:
+              - asc
+              - desc
+      example:
+        - field: created
+          direction: asc
+        - field: collection
+          direction: desc
+    sortbyFilter:
+      description: Sort the results by the specified fields.
+      properties:
+        sortby:
+          $ref: "#/components/schemas/sortby"
+      type: object
     searchBody:
       allOf:
         #        - $ref: "#/components/schemas/assetQueryFilter"
@@ -1964,6 +2001,7 @@ components:
         - $ref: "#/components/schemas/collectionsFilter"
         - $ref: "#/components/schemas/idsFilter"
         - $ref: "#/components/schemas/limitFilter"
+        - $ref: "#/components/schemas/sortbyFilter"
         - $ref: "#/components/schemas/forecast_reference_datetimeFilter"
         - $ref: "#/components/schemas/forecast_horizonFilter"
         - $ref: "#/components/schemas/forecast_durationFilter"
@@ -2108,6 +2146,7 @@ paths:
         - $ref: "#/components/parameters/limit"
         - $ref: "#/components/parameters/bbox"
         - $ref: "#/components/parameters/datetime"
+        - $ref: "#/components/parameters/sortby"
       responses:
         "200":
           $ref: "#/components/responses/Features"
@@ -2340,6 +2379,7 @@ paths:
         - $ref: "#/components/parameters/limit"
         - $ref: "#/components/parameters/ids"
         - $ref: "#/components/parameters/collectionsArray"
+        - $ref: "#/components/parameters/sortby"
       responses:
         "200":
           content:
diff --git a/spec/static/spec/v1/openapitransactional.yaml b/spec/static/spec/v1/openapitransactional.yaml
index 5092d347..0355269e 100644
--- a/spec/static/spec/v1/openapitransactional.yaml
+++ b/spec/static/spec/v1/openapitransactional.yaml
@@ -130,6 +130,15 @@ components:
       required: false
       schema:
         type: string
+    sortby:
+      name: sortby
+      in: query
+      description: >-
+        An array of property names, prefixed by either "+" for ascending or "-" for descending. If no prefix is provided, "+" is assumed.
+      required: false
+      schema:
+        type: string
+        example: '-created,id'
     uploadId:
       name: uploadId
       in: path
@@ -2038,6 +2047,34 @@ components:
       description: Purposes of the asset
       example:
         - thumbnail
+    sortby:
+      type: array
+      description: >-
+        An array of objects containing a property name and sort direction.
+      items:
+        type: object
+        required:
+          - field
+        properties:
+          field:
+            type: string
+          direction:
+            type: string
+            default: asc
+            enum:
+              - asc
+              - desc
+      example:
+        - field: created
+          direction: asc
+        - field: collection
+          direction: desc
+    sortbyFilter:
+      description: Sort the results by the specified fields.
+      properties:
+        sortby:
+          $ref: "#/components/schemas/sortby"
+      type: object
     searchBody:
       allOf:
         #        - $ref: "#/components/schemas/assetQueryFilter"
@@ -2048,6 +2085,7 @@ components:
         - $ref: "#/components/schemas/collectionsFilter"
         - $ref: "#/components/schemas/idsFilter"
         - $ref: "#/components/schemas/limitFilter"
+        - $ref: "#/components/schemas/sortbyFilter"
         - $ref: "#/components/schemas/forecast_reference_datetimeFilter"
         - $ref: "#/components/schemas/forecast_horizonFilter"
         - $ref: "#/components/schemas/forecast_durationFilter"
@@ -3070,6 +3108,7 @@ paths:
         - $ref: "#/components/parameters/limit"
         - $ref: "#/components/parameters/bbox"
         - $ref: "#/components/parameters/datetime"
+        - $ref: "#/components/parameters/sortby"
       responses:
         "200":
           $ref: "#/components/responses/Features"
@@ -3603,6 +3642,7 @@ paths:
         - $ref: "#/components/parameters/limit"
         - $ref: "#/components/parameters/ids"
         - $ref: "#/components/parameters/collectionsArray"
+        - $ref: "#/components/parameters/sortby"
       responses:
         "200":
           content: