diff --git a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufDecoder.java b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufDecoder.java
index 442e255d02c..81fa9ce5600 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufDecoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufDecoder.java
@@ -173,6 +173,19 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 		}
 	}
 
+	/**
+	 * Create a new {@code Message.Builder} instance for the given class.
+	 * <p>This method uses a ConcurrentHashMap for caching method lookups.
+	 */
+	protected static Message.Builder getMessageBuilder(Class<?> clazz) throws Exception {
+		Method method = methodCache.get(clazz);
+		if (method == null) {
+			method = clazz.getMethod("newBuilder");
+			methodCache.put(clazz, method);
+		}
+		return (Message.Builder) method.invoke(clazz);
+	}
+
 	/**
 	 * Use merge methods on {@link Message.Builder} to read a single message
 	 * from the given {@code DataBuffer}.
@@ -184,20 +197,6 @@ public class ProtobufDecoder extends ProtobufCodecSupport implements Decoder<Mes
 		builder.mergeFrom(CodedInputStream.newInstance(byteBuffer), this.extensionRegistry);
 	}
 
-
-	/**
-	 * Create a new {@code Message.Builder} instance for the given class.
-	 * <p>This method uses a ConcurrentHashMap for caching method lookups.
-	 */
-	private static Message.Builder getMessageBuilder(Class<?> clazz) throws Exception {
-		Method method = methodCache.get(clazz);
-		if (method == null) {
-			method = clazz.getMethod("newBuilder");
-			methodCache.put(clazz, method);
-		}
-		return (Message.Builder) method.invoke(clazz);
-	}
-
 	@Override
 	public List<MimeType> getDecodableMimeTypes() {
 		return getMimeTypes();
diff --git a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufEncoder.java b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufEncoder.java
index 6230591ba2a..227c57c5f8b 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufEncoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufEncoder.java
@@ -54,6 +54,7 @@ import org.springframework.util.MimeType;
  *
  * @author Sebastien Deleuze
  * @since 5.1
+ * @see ProtobufHttpMessageWriter
  * @see ProtobufDecoder
  */
 public class ProtobufEncoder extends ProtobufCodecSupport implements HttpMessageEncoder<Message> {
diff --git a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufHttpMessageWriter.java b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufHttpMessageWriter.java
index 103c5dea6fc..1ec9f50e3b0 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufHttpMessageWriter.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufHttpMessageWriter.java
@@ -95,6 +95,19 @@ public class ProtobufHttpMessageWriter extends EncoderHttpMessageWriter<Message>
 		}
 	}
 
+	/**
+	 * Create a new {@code Message.Builder} instance for the given class.
+	 * <p>This method uses a ConcurrentHashMap for caching method lookups.
+	 */
+	protected static Message.Builder getMessageBuilder(Class<?> clazz) throws Exception {
+		Method method = methodCache.get(clazz);
+		if (method == null) {
+			method = clazz.getMethod("newBuilder");
+			methodCache.put(clazz, method);
+		}
+		return (Message.Builder) method.invoke(clazz);
+	}
+
 	/**
 	 * Return the {@code MediaType} to use when the input Publisher is multivalued.
 	 * @since 7.0
@@ -118,17 +131,4 @@ public class ProtobufHttpMessageWriter extends EncoderHttpMessageWriter<Message>
 	protected void extendHeaders(ReactiveHttpOutputMessage message, Map<String, Object> hints) {
 	}
 
-	/**
-	 * Create a new {@code Message.Builder} instance for the given class.
-	 * <p>This method uses a ConcurrentHashMap for caching method lookups.
-	 */
-	private static Message.Builder getMessageBuilder(Class<?> clazz) throws Exception {
-		Method method = methodCache.get(clazz);
-		if (method == null) {
-			method = clazz.getMethod("newBuilder");
-			methodCache.put(clazz, method);
-		}
-		return (Message.Builder) method.invoke(clazz);
-	}
-
 }
diff --git a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonDecoder.java b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonDecoder.java
index 0bb13897dea..de5dd6cee05 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonDecoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonDecoder.java
@@ -161,7 +161,7 @@ public class ProtobufJsonDecoder implements Decoder<Message> {
 	 * Create a new {@code Message.Builder} instance for the given class.
 	 * <p>This method uses a ConcurrentHashMap for caching method lookups.
 	 */
-	private static Message.Builder getMessageBuilder(Class<?> clazz) throws Exception {
+	protected static Message.Builder getMessageBuilder(Class<?> clazz) throws Exception {
 		Method method = methodCache.get(clazz);
 		if (method == null) {
 			method = clazz.getMethod("newBuilder");
diff --git a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoder.java b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoder.java
index ef42819cd3c..ae549111946 100644
--- a/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoder.java
+++ b/spring-web/src/main/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoder.java
@@ -49,6 +49,7 @@ import org.springframework.util.MimeType;
  *
  * @author Brian Clozel
  * @since 6.2
+ * @see ProtobufHttpMessageWriter
  * @see ProtobufJsonDecoder
  */
 public class ProtobufJsonEncoder implements HttpMessageEncoder<Message> {
@@ -59,7 +60,8 @@ public class ProtobufJsonEncoder implements HttpMessageEncoder<Message> {
 
 	private static final List<MimeType> defaultMimeTypes = List.of(
 			MediaType.APPLICATION_JSON,
-			new MediaType("application", "*+json"));
+			new MediaType("application", "*+json"),
+			MediaType.APPLICATION_NDJSON);
 
 	private final JsonFormat.Printer printer;
 
@@ -106,7 +108,10 @@ public class ProtobufJsonEncoder implements HttpMessageEncoder<Message> {
 	}
 
 	@Override
-	public Flux<DataBuffer> encode(Publisher<? extends Message> inputStream, DataBufferFactory bufferFactory, ResolvableType elementType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+	public Flux<DataBuffer> encode(
+			Publisher<? extends Message> inputStream, DataBufferFactory bufferFactory,
+			ResolvableType elementType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+
 		if (inputStream instanceof Mono) {
 			return Mono.from(inputStream)
 					.map(value -> encodeValue(value, bufferFactory, elementType, mimeType, hints))
@@ -120,17 +125,21 @@ public class ProtobufJsonEncoder implements HttpMessageEncoder<Message> {
 				.map(value -> {
 					byte[] prefix = helper.getPrefix();
 					byte[] delimiter = helper.getDelimiter();
+					DataBuffer delimiterBuffer = bufferFactory.wrap(delimiter);
 					DataBuffer dataBuffer = encodeValue(value, bufferFactory, MESSAGE_TYPE, mimeType, hints);
 					return (prefix.length > 0 ?
-							bufferFactory.join(List.of(bufferFactory.wrap(prefix), bufferFactory.wrap(delimiter), dataBuffer)) :
-							bufferFactory.join(List.of(bufferFactory.wrap(delimiter), dataBuffer)));
+							bufferFactory.join(List.of(bufferFactory.wrap(prefix), delimiterBuffer, dataBuffer)) :
+							bufferFactory.join(List.of(delimiterBuffer, dataBuffer)));
 				})
 				.switchIfEmpty(Mono.fromCallable(() -> bufferFactory.wrap(helper.getPrefix())))
 				.concatWith(Mono.fromCallable(() -> bufferFactory.wrap(helper.getSuffix())));
 	}
 
 	@Override
-	public DataBuffer encodeValue(Message message, DataBufferFactory bufferFactory, ResolvableType valueType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+	public DataBuffer encodeValue(
+			Message message, DataBufferFactory bufferFactory, ResolvableType valueType,
+			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+
 		FastByteArrayOutputStream bos = new FastByteArrayOutputStream();
 		OutputStreamWriter writer = new OutputStreamWriter(bos, StandardCharsets.UTF_8);
 		try {
@@ -144,6 +153,7 @@ public class ProtobufJsonEncoder implements HttpMessageEncoder<Message> {
 		}
 	}
 
+
 	private static class JsonArrayJoinHelper {
 
 		private static final byte[] COMMA_SEPARATOR = {','};
diff --git a/spring-web/src/test/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoderTests.java b/spring-web/src/test/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoderTests.java
index ed7b6d4224a..2924b0aa731 100644
--- a/spring-web/src/test/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoderTests.java
+++ b/spring-web/src/test/java/org/springframework/http/codec/protobuf/ProtobufJsonEncoderTests.java
@@ -43,22 +43,28 @@ import static org.springframework.core.ResolvableType.forClass;
  */
 class ProtobufJsonEncoderTests extends AbstractEncoderTests<ProtobufJsonEncoder> {
 
-	private Msg msg1 =
-			Msg.newBuilder().setFoo("Foo").setBlah(SecondMsg.newBuilder().setBlah(123).build()).build();
+	private Msg msg1 = Msg.newBuilder()
+			.setFoo("Foo")
+			.setBlah(SecondMsg.newBuilder().setBlah(123).build())
+			.build();
+
+	private Msg msg2 = Msg.newBuilder()
+			.setFoo("Bar")
+			.setBlah(SecondMsg.newBuilder().setBlah(456).build())
+			.build();
 
-	private Msg msg2 =
-			Msg.newBuilder().setFoo("Bar").setBlah(SecondMsg.newBuilder().setBlah(456).build()).build();
 
 	public ProtobufJsonEncoderTests() {
 		super(new ProtobufJsonEncoder(JsonFormat.printer().omittingInsignificantWhitespace()));
 	}
 
+
 	@Override
 	@Test
 	protected void canEncode() throws Exception {
 		assertThat(this.encoder.canEncode(forClass(Msg.class), null)).isFalse();
 		assertThat(this.encoder.canEncode(forClass(Msg.class), MediaType.APPLICATION_JSON)).isTrue();
-		assertThat(this.encoder.canEncode(forClass(Msg.class), MediaType.APPLICATION_NDJSON)).isFalse();
+		assertThat(this.encoder.canEncode(forClass(Msg.class), MediaType.APPLICATION_NDJSON)).isTrue();
 		assertThat(this.encoder.canEncode(forClass(Object.class), MediaType.APPLICATION_JSON)).isFalse();
 	}
 
@@ -69,7 +75,7 @@ class ProtobufJsonEncoderTests extends AbstractEncoderTests<ProtobufJsonEncoder>
 		ResolvableType inputType = forClass(Msg.class);
 
 		testEncode(input, inputType, MediaType.APPLICATION_JSON, null, step -> step
-				.assertNext(dataBuffer -> assertBufferEqualsJson(dataBuffer, "{\"foo\":\"Foo\",\"blah\":{\"blah\":123}}"))
+				.assertNext(buffer -> assertBufferEqualsJson(buffer, "{\"foo\":\"Foo\",\"blah\":{\"blah\":123}}"))
 				.verifyComplete());
 		testEncodeError(input, inputType, MediaType.APPLICATION_JSON, null);
 		testEncodeCancel(input, inputType, MediaType.APPLICATION_JSON, null);
@@ -91,9 +97,9 @@ class ProtobufJsonEncoderTests extends AbstractEncoderTests<ProtobufJsonEncoder>
 		ResolvableType inputType = forClass(Msg.class);
 
 		testEncode(input, inputType, MediaType.APPLICATION_JSON, null, step -> step
-				.assertNext(dataBuffer -> assertBufferEqualsJson(dataBuffer, "[{\"foo\":\"Foo\",\"blah\":{\"blah\":123}}"))
-				.assertNext(dataBuffer -> assertBufferEqualsJson(dataBuffer, ",{\"foo\":\"Bar\",\"blah\":{\"blah\":456}}"))
-				.assertNext(dataBuffer -> assertBufferEqualsJson(dataBuffer, "]"))
+				.assertNext(buffer -> assertBufferEqualsJson(buffer, "[{\"foo\":\"Foo\",\"blah\":{\"blah\":123}}"))
+				.assertNext(buffer -> assertBufferEqualsJson(buffer, ",{\"foo\":\"Bar\",\"blah\":{\"blah\":456}}"))
+				.assertNext(buffer -> assertBufferEqualsJson(buffer, "]"))
 				.verifyComplete());
 	}