diff --git a/documentcloud/addons/tests/test_views.py b/documentcloud/addons/tests/test_views.py
index 21a285f4..da6cf4a9 100644
--- a/documentcloud/addons/tests/test_views.py
+++ b/documentcloud/addons/tests/test_views.py
@@ -309,6 +309,44 @@ def test_filter_site_absent_is_noop(self, client):
         assert response.status_code == status.HTTP_200_OK
         assert len(response.json()["results"]) == 3
 
+    def test_filter_domain(self, client):
+        """Filter runs by the host of the event's parameters.site"""
+        user = UserFactory()
+        matching_event = AddOnEventFactory(
+            user=user,
+            parameters={
+                "site": "https://www.nifc.gov/fire-information/statistics/wildfires",
+                "selector": "*",
+            },
+        )
+        other_event = AddOnEventFactory(
+            user=user, parameters={"site": "https://www.other.com/path"}
+        )
+        no_site_event = AddOnEventFactory(user=user, parameters={"selector": "*"})
+        matching_run = AddOnRunFactory(user=user, event=matching_event)
+        AddOnRunFactory(user=user, event=other_event)
+        AddOnRunFactory(user=user, event=no_site_event)
+        AddOnRunFactory(user=user, event=None)
+        client.force_authenticate(user=user)
+        # bare host and full origin both match, regardless of path
+        for domain in ("www.nifc.gov", "https://www.nifc.gov"):
+            response = client.get("/api/addon_runs/", {"domain": domain})
+            assert response.status_code == status.HTTP_200_OK
+            uuids = [r["uuid"] for r in response.json()["results"]]
+            assert uuids == [str(matching_run.uuid)], domain
+
+    def test_filter_domain_no_partial_host_match(self, client):
+        """The domain filter matches whole hosts, not substrings"""
+        user = UserFactory()
+        event = AddOnEventFactory(
+            user=user, parameters={"site": "https://www.nifc.gov.evil.com/path"}
+        )
+        AddOnRunFactory(user=user, event=event)
+        client.force_authenticate(user=user)
+        response = client.get("/api/addon_runs/", {"domain": "www.nifc.gov"})
+        assert response.status_code == status.HTTP_200_OK
+        assert response.json()["results"] == []
+
 
 @pytest.mark.django_db()
 class TestAddOnEventAPI:
@@ -351,6 +389,25 @@ def test_filter_site_no_match(self, client):
         assert response.status_code == status.HTTP_200_OK
         assert response.json()["results"] == []
 
+    def test_filter_domain(self, client):
+        """Filter events by the host of their parameters.site"""
+        user = UserFactory()
+        matching = AddOnEventFactory(
+            user=user,
+            parameters={
+                "site": "https://www.nifc.gov/fire-information/statistics/wildfires",
+                "selector": "*",
+            },
+        )
+        AddOnEventFactory(user=user, parameters={"site": "https://www.other.com/path"})
+        AddOnEventFactory(user=user, parameters={"selector": "*"})
+        client.force_authenticate(user=user)
+        for domain in ("www.nifc.gov", "https://www.nifc.gov"):
+            response = client.get("/api/addon_events/", {"domain": domain})
+            assert response.status_code == status.HTTP_200_OK
+            ids = [r["id"] for r in response.json()["results"]]
+            assert ids == [matching.pk], domain
+
     def test_filter_message(self, client):
         """Filter runs by message"""
         user = UserFactory()
diff --git a/documentcloud/addons/views.py b/documentcloud/addons/views.py
index acd03fd0..3e643b4f 100644
--- a/documentcloud/addons/views.py
+++ b/documentcloud/addons/views.py
@@ -30,6 +30,7 @@
 import hmac
 import json
 import logging
+import re
 from collections import defaultdict
 from datetime import timedelta
 from functools import lru_cache
@@ -65,6 +66,21 @@
 logger = logging.getLogger(__name__)
 
 
+def domain_site_regex(value):
+    """Build a regex matching `site` URLs whose host equals the given domain.
+
+    Accepts either a bare host (`www.nifc.gov`) or a full URL
+    (`https://www.nifc.gov/path`) and matches stored site values regardless of
+    scheme, port, path or query string. Returns None if no host can be parsed.
+    """
+    value = value.strip()
+    # furl only parses the host when an authority is present, so ensure one
+    host = furl(value if "//" in value else "//" + value).host
+    if not host:
+        return None
+    return r"^(https?://)?" + re.escape(host) + r"(:\d+)?($|[/?#])"
+
+
 class AddOnViewSet(viewsets.ModelViewSet):
     serializer_class = AddOnSerializer
     queryset = AddOn.objects.none()
@@ -746,6 +762,14 @@ class Filter(django_filters.FilterSet):
             label="Site",
             help_text="Filter runs by the `site` value in the event's parameters.",
         )
+        domain = django_filters.CharFilter(
+            method="domain_filter",
+            label="Domain",
+            help_text=(
+                "Filter runs by the host of the event's `site` parameter, e.g. "
+                "`www.nifc.gov` or `https://www.nifc.gov`."
+            ),
+        )
         message = django_filters.CharFilter(
             field_name="message",
             lookup_expr="exact",
@@ -753,6 +777,13 @@ class Filter(django_filters.FilterSet):
             help_text="Filter runs by their progress message.",
         )
 
+        def domain_filter(self, queryset, name, value):
+            # pylint: disable=unused-argument
+            pattern = domain_site_regex(value)
+            if pattern is None:
+                return queryset.none()
+            return queryset.filter(event__parameters__site__iregex=pattern)
+
         class Meta:
             model = AddOnRun
             fields = {
@@ -988,6 +1019,21 @@ class Filter(django_filters.FilterSet):
             label="Site",
             help_text="Filter events by the `site` value in their parameters.",
         )
+        domain = django_filters.CharFilter(
+            method="domain_filter",
+            label="Domain",
+            help_text=(
+                "Filter events by the host of their `site` parameter, e.g. "
+                "`www.nifc.gov` or `https://www.nifc.gov`."
+            ),
+        )
+
+        def domain_filter(self, queryset, name, value):
+            # pylint: disable=unused-argument
+            pattern = domain_site_regex(value)
+            if pattern is None:
+                return queryset.none()
+            return queryset.filter(parameters__site__iregex=pattern)
 
         class Meta:
             model = AddOnEvent