diff --git a/api/src/main/java/ai/djl/modality/Output.java b/api/src/main/java/ai/djl/modality/Output.java
index 965f12c07c0..be8f942c792 100644
--- a/api/src/main/java/ai/djl/modality/Output.java
+++ b/api/src/main/java/ai/djl/modality/Output.java
@@ -27,26 +27,24 @@ public class Output {
     private byte[] content;
 
     /**
-     * Constructs a {@code Output} with specified {@code requestId}.
+     * Constructs a {@code Output} with specified {@code requestId}, {@code code} and {@code
+     * message}.
      *
-     * @param requestId the requestId of the output
+     * @param code the status code of the output
+     * @param message the status message of the output
      */
-    public Output(String requestId) {
-        this.requestId = requestId;
+    public Output(int code, String message) {
+        this.code = code;
+        this.message = message;
     }
 
     /**
-     * Constructs a {@code Output} with specified {@code requestId}, {@code code} and {@code
-     * message}.
+     * Sets the requestId of the output.
      *
      * @param requestId the requestId of the output
-     * @param code the status code of the output
-     * @param message the status message of the output
      */
-    public Output(String requestId, int code, String message) {
+    public void setRequestId(String requestId) {
         this.requestId = requestId;
-        this.code = code;
-        this.message = message;
     }
 
     /**
diff --git a/api/src/main/java/ai/djl/translate/ServingTranslatorFactory.java b/api/src/main/java/ai/djl/translate/ServingTranslatorFactory.java
index 2d5b707b3a0..c40e2b9acea 100644
--- a/api/src/main/java/ai/djl/translate/ServingTranslatorFactory.java
+++ b/api/src/main/java/ai/djl/translate/ServingTranslatorFactory.java
@@ -189,7 +189,11 @@ private Translator<Input, Output> loadDefaultTranslator(Map<String, ?> arguments
                 return getSsdTranslator(arguments);
             }
         }
-        return new RawTranslator();
+        String batchifier = (String) arguments.get("batchifier");
+        if (batchifier == null) {
+            return new RawTranslator(null);
+        }
+        return new RawTranslator(Batchifier.fromString(batchifier));
     }
 
     private Translator<Input, Output> getImageClassificationTranslator(Map<String, ?> arguments) {
@@ -239,8 +243,7 @@ public Batchifier getBatchifier() {
         /** {@inheritDoc} */
         @Override
         public Output processOutput(TranslatorContext ctx, NDList list) throws Exception {
-            Input input = (Input) ctx.getAttachment("input");
-            Output output = new Output(input.getRequestId(), 200, "OK");
+            Output output = new Output(200, "OK");
             Object obj = translator.processOutput(ctx, list);
             if (obj instanceof JsonSerializable) {
                 output.setContent(((JsonSerializable) obj).toJson() + '\n');
@@ -280,16 +283,21 @@ public void prepare(NDManager manager, Model model) throws IOException {
 
     private static final class RawTranslator implements Translator<Input, Output> {
 
+        private Batchifier batchifier;
+
+        RawTranslator(Batchifier batchifier) {
+            this.batchifier = batchifier;
+        }
+
         /** {@inheritDoc} */
         @Override
         public Batchifier getBatchifier() {
-            return null;
+            return batchifier;
         }
 
         /** {@inheritDoc} */
         @Override
         public NDList processInput(TranslatorContext ctx, Input input) throws TranslateException {
-            ctx.setAttachment("input", input);
             PairList<String, byte[]> inputs = input.getContent();
             byte[] data = inputs.get("data");
             if (data == null) {
@@ -309,8 +317,7 @@ public NDList processInput(TranslatorContext ctx, Input input) throws TranslateE
         /** {@inheritDoc} */
         @Override
         public Output processOutput(TranslatorContext ctx, NDList list) {
-            Input input = (Input) ctx.getAttachment("input");
-            Output output = new Output(input.getRequestId(), 200, "OK");
+            Output output = new Output(200, "OK");
             output.setContent(list.encode());
             output.addProperty("Content-Type", "tensor/ndlist");
             return output;
diff --git a/serving/serving/src/main/java/ai/djl/serving/http/ManagementRequestHandler.java b/serving/serving/src/main/java/ai/djl/serving/http/ManagementRequestHandler.java
index 088598d04e3..79d24fff0f3 100644
--- a/serving/serving/src/main/java/ai/djl/serving/http/ManagementRequestHandler.java
+++ b/serving/serving/src/main/java/ai/djl/serving/http/ManagementRequestHandler.java
@@ -55,7 +55,7 @@ public class ManagementRequestHandler extends HttpRequestHandler {
     /** HTTP Parameter "max_batch_delay". */
     private static final String MAX_BATCH_DELAY_PARAMETER = "max_batch_delay";
     /** HTTP Parameter "max_idle_time". */
-    private static final String MAX_IDLE_TIME__PARAMETER = "max_idle_time";
+    private static final String MAX_IDLE_TIME_PARAMETER = "max_idle_time";
     /** HTTP Parameter "max_worker". */
     private static final String MAX_WORKER_PARAMETER = "max_worker";
     /** HTTP Parameter "min_worker". */
@@ -166,7 +166,7 @@ private void handleRegisterModel(final ChannelHandlerContext ctx, QueryStringDec
         String engineName = NettyUtils.getParameter(decoder, ENGINE_NAME_PARAMETER, null);
         int batchSize = NettyUtils.getIntParameter(decoder, BATCH_SIZE_PARAMETER, 1);
         int maxBatchDelay = NettyUtils.getIntParameter(decoder, MAX_BATCH_DELAY_PARAMETER, 100);
-        int maxIdleTime = NettyUtils.getIntParameter(decoder, MAX_IDLE_TIME__PARAMETER, 60);
+        int maxIdleTime = NettyUtils.getIntParameter(decoder, MAX_IDLE_TIME_PARAMETER, 60);
         int minWorkers = NettyUtils.getIntParameter(decoder, MIN_WORKER_PARAMETER, 1);
         int defaultWorkers = ConfigManager.getInstance().getDefaultWorkers();
         int maxWorkers = NettyUtils.getIntParameter(decoder, MAX_WORKER_PARAMETER, defaultWorkers);
@@ -239,7 +239,7 @@ private void handleScaleModel(
 
             int maxIdleTime =
                     NettyUtils.getIntParameter(
-                            decoder, MAX_IDLE_TIME__PARAMETER, modelInfo.getMaxIdleTime());
+                            decoder, MAX_IDLE_TIME_PARAMETER, modelInfo.getMaxIdleTime());
             int batchSize =
                     NettyUtils.getIntParameter(
                             decoder, BATCH_SIZE_PARAMETER, modelInfo.getBatchSize());
diff --git a/serving/serving/src/main/java/ai/djl/serving/wlm/BatchAggregator.java b/serving/serving/src/main/java/ai/djl/serving/wlm/BatchAggregator.java
index daa9f11a45e..25ed8515d35 100644
--- a/serving/serving/src/main/java/ai/djl/serving/wlm/BatchAggregator.java
+++ b/serving/serving/src/main/java/ai/djl/serving/wlm/BatchAggregator.java
@@ -18,6 +18,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.LinkedBlockingDeque;
+import java.util.concurrent.TimeUnit;
 
 /**
  * abstract class for all BatchAggregators. A batch aggregator check working queue and combines
@@ -28,6 +29,7 @@
 abstract class BatchAggregator {
 
     protected int batchSize;
+    protected int maxBatchDelay;
     protected List<Job> jobs;
     protected LinkedBlockingDeque<Job> jobQueue;
 
@@ -39,6 +41,7 @@ abstract class BatchAggregator {
      */
     public BatchAggregator(ModelInfo model, LinkedBlockingDeque<Job> jobQueue) {
         this.batchSize = model.getBatchSize();
+        this.maxBatchDelay = model.getMaxBatchDelay();
         this.jobQueue = jobQueue;
         jobs = new ArrayList<>();
     }
@@ -72,11 +75,8 @@ public void sendResponse(List<Output> outputs) {
 
         int i = 0;
         for (Output output : outputs) {
-            String requestId = output.getRequestId();
             Job job = jobs.get(i++);
-            if (!job.getRequestId().equals(requestId)) {
-                throw new IllegalStateException("Request response mismatched.");
-            }
+            output.setRequestId(job.getRequestId());
             job.sendOutput(output);
         }
         jobs.clear();
@@ -111,4 +111,23 @@ public void sendError(HttpResponseStatus status, Throwable error) {
      *     temporary batch aggregator.
      */
     public abstract boolean isFinished();
+
+    protected void drainTo(List<Job> list, int maxDelay) throws InterruptedException {
+        long begin = System.currentTimeMillis();
+        jobQueue.drainTo(list, batchSize - 1);
+        int remain = batchSize - list.size();
+        for (int i = 0; i < remain; ++i) {
+            Job job = jobQueue.poll(maxDelay, TimeUnit.MILLISECONDS);
+            if (job == null) {
+                break;
+            }
+            long end = System.currentTimeMillis();
+            maxDelay -= end - begin;
+            begin = end;
+            list.add(job);
+            if (maxDelay <= 0) {
+                break;
+            }
+        }
+    }
 }
diff --git a/serving/serving/src/main/java/ai/djl/serving/wlm/ModelManager.java b/serving/serving/src/main/java/ai/djl/serving/wlm/ModelManager.java
index 470ce0f1802..539d964d77e 100644
--- a/serving/serving/src/main/java/ai/djl/serving/wlm/ModelManager.java
+++ b/serving/serving/src/main/java/ai/djl/serving/wlm/ModelManager.java
@@ -106,6 +106,9 @@ public CompletableFuture<ModelInfo> registerModel(
                         } else {
                             logger.info("Loading model {} on {}.", modelName, Device.cpu());
                         }
+                        if (batchSize > 1) {
+                            builder.optArgument("batchifier", "stack");
+                        }
 
                         ZooModel<Input, Output> model = builder.build().loadModel();
                         ModelInfo modelInfo =
diff --git a/serving/serving/src/main/java/ai/djl/serving/wlm/PermanentBatchAggregator.java b/serving/serving/src/main/java/ai/djl/serving/wlm/PermanentBatchAggregator.java
index 0321cc8cf62..b7d5637fedc 100644
--- a/serving/serving/src/main/java/ai/djl/serving/wlm/PermanentBatchAggregator.java
+++ b/serving/serving/src/main/java/ai/djl/serving/wlm/PermanentBatchAggregator.java
@@ -44,7 +44,8 @@ protected List<Job> pollBatch() throws InterruptedException {
         List<Job> list = new ArrayList<>(batchSize);
         Job job = jobQueue.take();
         list.add(job);
-        jobQueue.drainTo(list, batchSize - 1);
+        logger.trace("get first job: {}", job.getRequestId());
+        drainTo(list, maxBatchDelay);
         logger.trace("sending jobs, size: {}", list.size());
         return list;
     }
diff --git a/serving/serving/src/main/java/ai/djl/serving/wlm/TemporaryBatchAggregator.java b/serving/serving/src/main/java/ai/djl/serving/wlm/TemporaryBatchAggregator.java
index 6e990a72e70..e3dc134859f 100644
--- a/serving/serving/src/main/java/ai/djl/serving/wlm/TemporaryBatchAggregator.java
+++ b/serving/serving/src/main/java/ai/djl/serving/wlm/TemporaryBatchAggregator.java
@@ -50,7 +50,7 @@ protected List<Job> pollBatch() throws InterruptedException {
         Job job = jobQueue.poll(maxIdleTime, TimeUnit.SECONDS);
         if (job != null) {
             list.add(job);
-            jobQueue.drainTo(list, batchSize - 1);
+            drainTo(list, maxBatchDelay);
             logger.trace("sending jobs, size: {}", list.size());
             idleSince = System.currentTimeMillis();
         }