diff --git a/java/google/registry/xml/XmlTransformer.java b/java/google/registry/xml/XmlTransformer.java
index 30b0b8cb9..6ccd5713c 100644
--- a/java/google/registry/xml/XmlTransformer.java
+++ b/java/google/registry/xml/XmlTransformer.java
@@ -303,6 +303,7 @@ public class XmlTransformer {
     try {
       Transformer transformer = transformerFactory.newTransformer();
       transformer.setOutputProperty(OutputKeys.INDENT, "yes");
+      transformer.setOutputProperty(OutputKeys.STANDALONE, "yes");
       transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
       transformer.transform(
           new StreamSource(new StringReader(xmlString)),
diff --git a/javatests/google/registry/flows/FlowRunnerTest.java b/javatests/google/registry/flows/FlowRunnerTest.java
index 1995be773..e9772765e 100644
--- a/javatests/google/registry/flows/FlowRunnerTest.java
+++ b/javatests/google/registry/flows/FlowRunnerTest.java
@@ -132,7 +132,8 @@ public class FlowRunnerTest extends ShardableTestCase {
             "TheRegistrar",
             "StatelessRequestSessionMetadata"
                 + "{clientId=TheRegistrar, failedLoginAttempts=0, serviceExtensionUris=}",
-            "<?xml version=\"1.0\" encoding=\"UTF-8\"?><xml/>",
+            "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>",
+            "<xml/>",
             "", // Extra newline at the end of the XML.
             "PasswordOnlyTransportCredentials{}",
             "UNIT_TEST",
diff --git a/javatests/google/registry/flows/testdata/domain_create_prettyprinted.xml b/javatests/google/registry/flows/testdata/domain_create_prettyprinted.xml
index 785c293be..eebc36788 100644
--- a/javatests/google/registry/flows/testdata/domain_create_prettyprinted.xml
+++ b/javatests/google/registry/flows/testdata/domain_create_prettyprinted.xml
@@ -1,4 +1,5 @@
-<?xml version="1.0" encoding="UTF-8"?><epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<epp xmlns="urn:ietf:params:xml:ns:epp-1.0">
   <command>
     <create>
       <domain:create xmlns:domain="urn:ietf:params:xml:ns:domain-1.0">
diff --git a/javatests/google/registry/tools/EppToolVerifier.java b/javatests/google/registry/tools/EppToolVerifier.java
index 31e12e690..f2b95917a 100644
--- a/javatests/google/registry/tools/EppToolVerifier.java
+++ b/javatests/google/registry/tools/EppToolVerifier.java
@@ -17,6 +17,7 @@ package google.registry.tools;
 import static com.google.common.base.Preconditions.checkState;
 import static com.google.common.truth.Truth.assertThat;
 import static google.registry.xml.XmlTestUtils.assertXmlEquals;
+import static google.registry.xml.XmlTransformer.prettyPrint;
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.atLeast;
@@ -191,9 +192,7 @@ public class EppToolVerifier {
   private EppToolVerifier verifySentContents(String expectedXmlContent) throws Exception {
     setArgumentsIfNeeded();
     assertThat(capturedParams.size()).isGreaterThan(paramIndex);
-    assertXmlEquals(
-        expectedXmlContent,
-        bytesToXml(capturedParams.get(paramIndex)));
+    assertXmlEquals(expectedXmlContent, prettyPrint(bytesToXml(capturedParams.get(paramIndex))));
     paramIndex++;
     return this;
   }
diff --git a/javatests/google/registry/tools/GetHistoryEntriesCommandTest.java b/javatests/google/registry/tools/GetHistoryEntriesCommandTest.java
index 4b74dd854..fc17977a1 100644
--- a/javatests/google/registry/tools/GetHistoryEntriesCommandTest.java
+++ b/javatests/google/registry/tools/GetHistoryEntriesCommandTest.java
@@ -55,7 +55,8 @@ public class GetHistoryEntriesCommandTest extends CommandTestCase<GetHistoryEntr
             + "Time: 2000-01-01T00:00:00.000Z\n"
             + "Client TRID: ABC-123\n"
             + "Server TRID: server-trid\n"
-            + "<?xml version=\"1.0\" encoding=\"UTF-8\"?><xml/>\n"
+            + "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n"
+            + "<xml/>\n"
             + "\n");
   }
 
@@ -77,7 +78,8 @@ public class GetHistoryEntriesCommandTest extends CommandTestCase<GetHistoryEntr
             + "Time: 2000-01-01T00:00:00.000Z\n"
             + "Client TRID: null\n"
             + "Server TRID: null\n"
-            + "<?xml version=\"1.0\" encoding=\"UTF-8\"?><xml/>\n"
+            + "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n"
+            + "<xml/>\n"
             + "\n");
   }
 }