google · gbrodman · Mar 30, 2026
diff --git a/core/src/main/java/google/registry/config/RegistryConfig.java b/core/src/main/java/google/registry/config/RegistryConfig.java
@@ -988,6 +988,19 @@ public static int provideRdapResultSetMaxSize() {
       return 100;
     }
 
+    /**
+     * Whether to include optional RDAP history results in domain responses.
+     *
+     * <p>The RDAP Response Profile (Feb 2024) section 2.3 specifies that while registration and
+     * expiration events are required, other types are optional. In an effort to reduce database
+     * load, we (by default) omit the optional events.
+     */
+    @Provides
+    @Config("rdapIncludeOptionalHistoryResults")
+    public static boolean provideRdapIncludeOptionalHistoryResults() {
+      return false;
+    }
+
     /**
      * Maximum QPS for the Google Cloud Monitoring V3 (aka Stackdriver) API. The QPS limit can be
      * adjusted by contacting Cloud Support.

diff --git a/core/src/main/java/google/registry/rdap/RdapJsonFormatter.java b/core/src/main/java/google/registry/rdap/RdapJsonFormatter.java
@@ -20,6 +20,8 @@
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static google.registry.model.EppResourceUtils.isLinked;
 import static google.registry.persistence.transaction.TransactionManagerFactory.replicaTm;
+import static google.registry.util.DateTimeUtils.toDateTime;
+import static google.registry.util.DateTimeUtils.toInstant;
 
 import com.github.benmanes.caffeine.cache.LoadingCache;
 import com.google.common.annotations.VisibleForTesting;
@@ -114,6 +116,10 @@ record HistoryTimeAndRegistrar(DateTime modificationTime, String registrarId) {}
   @Nullable
   String rdapTosStaticUrl;
 
+  @Inject
+  @Config("rdapIncludeOptionalHistoryResults")
+  boolean rdapIncludeOptionalHistoryResults;
+
   @Inject @RequestServerName String serverName;
   @Inject RdapAuthorization rdapAuthorization;
   @Inject Clock clock;
@@ -328,9 +334,27 @@ RdapDomain createRdapDomain(Domain domain, OutputDataType outputDataType) {
                 .setEventAction(EventAction.LAST_UPDATE_OF_RDAP_DATABASE)
                 .setEventDate(getRequestTime())
                 .build());
+    // RDAP Response Profile section 2.3.2.2:
+    // "The event of eventAction type last changed MUST be omitted if the domain has not been
+    // updated since it was created." While it is possible for the domain to be changed out of band
+    // (i.e. without updating lastEppUpdateTime), that can only happen for domains that have already
+    // been modified in some way. As a result, we can ignore those cases here.
+    if (domain.getLastEppUpdateTime() != null
+        && domain.getLastEppUpdateTime().isAfter(toInstant(domain.getCreationTime()))) {
+      // Creates an RDAP event object as defined by RFC 9083
+      builder
+          .eventsBuilder()
+          .add(
+              Event.builder()
+                  .setEventAction(EventAction.LAST_CHANGED)
+                  .setEventDate(toDateTime(domain.getLastEppUpdateTime()))
+                  .build());
+    }
     // RDAP Response Profile section 2.3.2 discusses optional events. We add some of those
     // here. We also add a few others we find interesting.
-    builder.eventsBuilder().addAll(makeOptionalEvents(domain));
+    if (rdapIncludeOptionalHistoryResults) {
+      builder.eventsBuilder().addAll(makeOptionalEvents(domain));
+    }
     // RDAP Response Profile section 2.4.1:
     // The domain object in the RDAP response MUST contain an entity with the Registrar role.
     //
@@ -756,14 +780,9 @@ private static ImmutableMap<EventAction, HistoryTimeAndRegistrar> getLastHistory
    * that we don't need to load HistoryEntries for "summary" responses).
    */
   private ImmutableList<Event> makeOptionalEvents(EppResource resource) {
+    ImmutableList.Builder<Event> eventsBuilder = new ImmutableList.Builder<>();
     ImmutableMap<EventAction, HistoryTimeAndRegistrar> lastHistoryOfType =
         getLastHistoryByType(resource);
-    ImmutableList.Builder<Event> eventsBuilder = new ImmutableList.Builder<>();
-    DateTime creationTime = resource.getCreationTime();
-    DateTime lastChangeTime =
-        resource.getLastEppUpdateDateTime() == null
-            ? creationTime
-            : resource.getLastEppUpdateDateTime();
     // The order of the elements is stable - it's the order in which the enum elements are defined
     // in EventAction
     for (EventAction rdapEventAction : EventAction.values()) {
@@ -772,34 +791,11 @@ private ImmutableList<Event> makeOptionalEvents(EppResource resource) {
       if (historyTimeAndRegistrar == null) {
         continue;
       }
-      DateTime modificationTime = historyTimeAndRegistrar.modificationTime();
-      // We will ignore all events that happened before the "creation time", since these events are
-      // from a "previous incarnation of the domain" (for a domain that was owned by someone,
-      // deleted, and then bought by someone else)
-      if (modificationTime.isBefore(creationTime)) {
-        continue;
-      }
       eventsBuilder.add(
           Event.builder()
               .setEventAction(rdapEventAction)
               .setEventActor(historyTimeAndRegistrar.registrarId())
-              .setEventDate(modificationTime)
-              .build());
-      // The last change time might not be the lastEppUpdateTime, since some changes happen without
-      // any EPP update (for example, by the passage of time).
-      if (modificationTime.isAfter(lastChangeTime) && modificationTime.isBefore(getRequestTime())) {
-        lastChangeTime = modificationTime;
-      }
-    }
-    // RDAP Response Profile section 2.3.2.2:
-    // The event of eventAction type last changed MUST be omitted if the domain name has not been
-    // updated since it was created
-    if (lastChangeTime.isAfter(creationTime)) {
-      // Creates an RDAP event object as defined by RFC 9083
-      eventsBuilder.add(
-          Event.builder()
-              .setEventAction(EventAction.LAST_CHANGED)
-              .setEventDate(lastChangeTime)
+              .setEventDate(historyTimeAndRegistrar.modificationTime())
               .build());
     }
     return eventsBuilder.build();

diff --git a/core/src/test/java/google/registry/rdap/RdapJsonFormatterTest.java b/core/src/test/java/google/registry/rdap/RdapJsonFormatterTest.java
@@ -143,7 +143,7 @@ void beforeEach() {
             makeDomain("cat.みんな", hostIpv4, hostIpv6, registrar)
                 .asBuilder()
                 .setCreationTimeForTest(clock.nowUtc().minusMonths(4))
-                .setLastEppUpdateTime(clock.nowUtc().minusMonths(3))
+                .setLastEppUpdateTime(clock.nowUtc().minusMonths(1))
                 .build());
     domainNoNameserversNoTransfers =
         persistResource(
@@ -307,6 +307,14 @@ void testDomain_full() {
         .isEqualTo(loadJson("rdapjson_domain_full.json"));
   }
 
+  @Test
+  void testDomain_full_withHistory() {
+    rdapJsonFormatter.rdapIncludeOptionalHistoryResults = true;
+    assertAboutJson()
+        .that(rdapJsonFormatter.createRdapDomain(domainFull, OutputDataType.FULL).toJson())
+        .isEqualTo(loadJson("rdapjson_domain_full_with_history.json"));
+  }
+
   @Test
   void testDomain_summary() {
     assertAboutJson()
@@ -333,6 +341,15 @@ void testDomain_logged_out() {
         .isEqualTo(loadJson("rdapjson_domain_logged_out.json"));
   }
 
+  @Test
+  void testDomain_logged_out_withHistory() {
+    rdapJsonFormatter.rdapAuthorization = RdapAuthorization.PUBLIC_AUTHORIZATION;
+    rdapJsonFormatter.rdapIncludeOptionalHistoryResults = true;
+    assertAboutJson()
+        .that(rdapJsonFormatter.createRdapDomain(domainFull, OutputDataType.FULL).toJson())
+        .isEqualTo(loadJson("rdapjson_domain_logged_out_with_history.json"));
+  }
+
   @Test
   void testDomain_noNameserversNoTransfers() {
     assertAboutJson()

diff --git a/core/src/test/resources/google/registry/rdap/rdap_domain_deleted.json b/core/src/test/resources/google/registry/rdap/rdap_domain_deleted.json
@@ -42,11 +42,6 @@
       "eventAction": "last update of RDAP database",
       "eventDate": "2000-01-01T00:00:00.000Z"
     },
-    {
-      "eventAction": "deletion",
-      "eventActor": "evilregistrar",
-      "eventDate": "1999-07-01T00:00:00.000Z"
-    },
     {
       "eventAction": "last changed",
       "eventDate": "2009-05-29T20:13:00.000Z"

diff --git a/core/src/test/resources/google/registry/rdap/rdapjson_domain_full.json b/core/src/test/resources/google/registry/rdap/rdapjson_domain_full.json
@@ -37,11 +37,6 @@
       "eventAction": "last update of RDAP database",
       "eventDate": "2000-01-01T00:00:00.000Z"
     },
-    {
-      "eventAction": "transfer",
-      "eventActor": "unicoderegistrar",
-      "eventDate": "1999-12-01T00:00:00.000Z"
-    },
     {
       "eventAction": "last changed",
       "eventDate": "1999-12-01T00:00:00.000Z"

diff --git a/core/src/test/resources/google/registry/rdap/rdapjson_domain_full_with_history.json b/core/src/test/resources/google/registry/rdap/rdapjson_domain_full_with_history.json
@@ -0,0 +1,144 @@
+{
+  "objectClassName" : "domain",
+  "handle" : "F-Q9JYB4C",
+  "ldhName" : "cat.xn--q9jyb4c",
+  "unicodeName" : "cat.みんな",
+  "status" :
+    [
+      "client delete prohibited",
+      "client renew prohibited",
+      "client transfer prohibited",
+      "server update prohibited"
+    ],
+  "links" :
+  [
+    {
+      "rel" : "self",
+      "href" : "https://example.tld/rdap/domain/cat.xn--q9jyb4c",
+      "type" : "application/rdap+json"
+    },
+    {
+      "rel" : "related",
+      "href" : "https://rdap.example.com/withSlash/domain/cat.xn--q9jyb4c",
+      "type" : "application/rdap+json"
+    }
+  ],
+  "events": [
+    {
+      "eventAction": "registration",
+      "eventActor": "unicoderegistrar",
+      "eventDate": "1999-09-01T00:00:00.000Z"
+    },
+    {
+      "eventAction": "expiration",
+      "eventDate": "2110-10-08T00:44:59.000Z"
+    },
+    {
+      "eventAction": "last update of RDAP database",
+      "eventDate": "2000-01-01T00:00:00.000Z"
+    },
+    {
+      "eventAction": "last changed",
+      "eventDate": "1999-12-01T00:00:00.000Z"
+    },
+    {
+      "eventAction": "transfer",
+      "eventActor": "unicoderegistrar",
+      "eventDate": "1999-12-01T00:00:00.000Z"
+    }
+  ],
+  "nameservers" :
+  [
+    {
+      "objectClassName" : "nameserver",
+      "handle" : "2-ROID",
+      "ldhName" : "ns1.cat.xn--q9jyb4c",
+      "unicodeName" : "ns1.cat.みんな",
+      "links" : [
+        {
+          "rel" : "self",
+          "href" : "https://example.tld/rdap/nameserver/ns1.cat.xn--q9jyb4c",
+          "type" : "application/rdap+json"
+        }
+      ],
+      "remarks": [
+        {
+          "title": "Incomplete Data",
+          "type": "object truncated due to unexplainable reasons",
+          "description": ["Summary data only. For complete data, send a specific query for the object."]
+        }
+      ]
+    },
+    {
+      "objectClassName" : "nameserver",
+      "handle" : "4-ROID",
+      "ldhName" : "ns2.cat.xn--q9jyb4c",
+      "unicodeName" : "ns2.cat.みんな",
+      "links" : [
+        {
+          "rel" : "self",
+          "href" : "https://example.tld/rdap/nameserver/ns2.cat.xn--q9jyb4c",
+          "type" : "application/rdap+json"
+        }
+      ],
+      "remarks": [
+        {
+          "title": "Incomplete Data",
+          "type": "object truncated due to unexplainable reasons",
+          "description": ["Summary data only. For complete data, send a specific query for the object."]
+        }
+      ]
+    }
+  ],
+  "secureDNS": {
+    "delegationSigned": true,
+    "zoneSigned": true,
+    "dsData": [{"algorithm":2,"digest":"DEADFACE","digestType":3,"keyTag":1}]
+  },
+  "entities" :
+  [
+    {
+      "objectClassName" : "entity",
+      "handle" : "1",
+      "roles" : ["registrar"],
+      "links" :
+      [
+        {
+          "rel" : "self",
+          "href" : "https://example.tld/rdap/entity/1",
+          "type" : "application/rdap+json"
+        },
+        {
+          "rel": "about",
+          "href": "http://my.fake.url",
+          "type": "text/html",
+          "value": "https://rdap.example.com/withSlash/"
+        }
+      ],
+      "publicIds" :
+      [
+        {
+          "type" : "IANA Registrar ID",
+          "identifier" : "1"
+        }
+      ],
+      "vcardArray" :
+      [
+        "vcard",
+        [
+          ["version", {}, "text", "4.0"],
+          ["fn", {}, "text", "みんな"]
+        ]
+      ],
+      "remarks": [
+        {
+          "title": "Incomplete Data",
+          "description": [
+            "Summary data only. For complete data, send a specific query for the object."
+          ],
+          "type": "object truncated due to unexplainable reasons"
+        }
+      ]
+    }
+  ]
+}
diff --git a/core/src/test/resources/google/registry/rdap/rdapjson_domain_logged_out.json b/core/src/test/resources/google/registry/rdap/rdapjson_domain_logged_out.json
@@ -37,11 +37,6 @@
       "eventAction": "last update of RDAP database",
       "eventDate": "2000-01-01T00:00:00.000Z"
     },
-    {
-      "eventAction": "transfer",
-      "eventActor": "unicoderegistrar",
-      "eventDate": "1999-12-01T00:00:00.000Z"
-    },
     {
       "eventAction": "last changed",
       "eventDate": "1999-12-01T00:00:00.000Z"