diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5449aee..e6242e09 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,6 @@
+## 12.0.6
+ - Add headers reporting uncompressed size and doc count for bulk requests [#1217](https://github.com/logstash-plugins/logstash-output-elasticsearch/pull/1217)
+
 ## 12.0.5
  - [DOC] Fix link to Logstash DLQ docs [#1214](https://github.com/logstash-plugins/logstash-output-elasticsearch/pull/1214)
 
diff --git a/lib/logstash/outputs/elasticsearch/http_client.rb b/lib/logstash/outputs/elasticsearch/http_client.rb
index 120d3e67..8d6e02cb 100644
--- a/lib/logstash/outputs/elasticsearch/http_client.rb
+++ b/lib/logstash/outputs/elasticsearch/http_client.rb
@@ -21,7 +21,8 @@ module LogStash; module Outputs; class ElasticSearch;
   # We wound up agreeing that a number greater than 10 MiB and less than 100MiB
   # made sense. We picked one on the lowish side to not use too much heap.
   TARGET_BULK_BYTES = 20 * 1024 * 1024 # 20MiB
-
+  EVENT_COUNT_HEADER = "X-Elastic-Event-Count".freeze
+  UNCOMPRESSED_LENGTH_HEADER = "X-Elastic-Uncompressed-Request-Length".freeze
 
   class HttpClient
     attr_reader :client, :options, :logger, :pool, :action_count, :recv_count
@@ -143,7 +144,11 @@ def bulk(actions)
                        :payload_size => stream_writer.pos,
                        :content_length => body_stream.size,
                        :batch_offset => (index + 1 - batch_actions.size))
-          bulk_responses << bulk_send(body_stream, batch_actions)
+          headers = {
+            EVENT_COUNT_HEADER => batch_actions.size.to_s,
+            UNCOMPRESSED_LENGTH_HEADER => stream_writer.pos.to_s
+          }
+          bulk_responses << bulk_send(body_stream, batch_actions, headers)
           body_stream.truncate(0) && body_stream.seek(0)
           stream_writer = gzip_writer(body_stream) if compression_level?
           batch_actions.clear
@@ -159,7 +164,14 @@ def bulk(actions)
                    :payload_size => stream_writer.pos,
                    :content_length => body_stream.size,
                    :batch_offset => (actions.size - batch_actions.size))
-      bulk_responses << bulk_send(body_stream, batch_actions) if body_stream.size > 0
+
+      if body_stream.size > 0
+        headers = {
+          EVENT_COUNT_HEADER => batch_actions.size.to_s,
+          UNCOMPRESSED_LENGTH_HEADER => stream_writer.pos.to_s
+        }
+        bulk_responses << bulk_send(body_stream, batch_actions, headers)
+      end
 
       body_stream.close unless compression_level?
       join_bulk_responses(bulk_responses)
@@ -179,8 +191,8 @@ def join_bulk_responses(bulk_responses)
       }
     end
 
-    def bulk_send(body_stream, batch_actions)
-      params = compression_level? ? {:headers => {"Content-Encoding" => "gzip"}} : {}
+    def bulk_send(body_stream, batch_actions, headers = {})
+      params = compression_level? ? {:headers => headers.merge("Content-Encoding" => "gzip") } : { :headers => headers }
 
       begin
         response = @pool.post(@bulk_path, params, body_stream.string)
diff --git a/logstash-output-elasticsearch.gemspec b/logstash-output-elasticsearch.gemspec
index 8e65ca13..072f25d0 100644
--- a/logstash-output-elasticsearch.gemspec
+++ b/logstash-output-elasticsearch.gemspec
@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name            = 'logstash-output-elasticsearch'
-  s.version         = '12.0.5'
+  s.version         = '12.0.6'
   s.licenses        = ['apache-2.0']
   s.summary         = "Stores logs in Elasticsearch"
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"
diff --git a/spec/integration/outputs/compressed_indexing_spec.rb b/spec/integration/outputs/compressed_indexing_spec.rb
index c1c30550..f6bb2ad8 100644
--- a/spec/integration/outputs/compressed_indexing_spec.rb
+++ b/spec/integration/outputs/compressed_indexing_spec.rb
@@ -36,7 +36,9 @@
       {
         "Content-Encoding" => "gzip",
         "Content-Type" => "application/json",
-        'x-elastic-product-origin' => 'logstash-output-elasticsearch'
+        'x-elastic-product-origin' => 'logstash-output-elasticsearch',
+        'X-Elastic-Event-Count' => anything,
+        'X-Elastic-Uncompressed-Request-Length' => anything,
       }
     }
 
diff --git a/spec/integration/outputs/index_spec.rb b/spec/integration/outputs/index_spec.rb
index 35d031c4..496abdcc 100644
--- a/spec/integration/outputs/index_spec.rb
+++ b/spec/integration/outputs/index_spec.rb
@@ -215,12 +215,22 @@ def curl_and_get_json_response(url, method: :get, retrieve_err_payload: false);
 
     it "sets the correct content-type header" do
       expected_manticore_opts = {
-        :headers => {"Content-Type" => "application/json", 'x-elastic-product-origin' => 'logstash-output-elasticsearch'},
+        :headers => {
+          "Content-Type" => "application/json",
+          'x-elastic-product-origin' => 'logstash-output-elasticsearch',
+          'X-Elastic-Event-Count' => anything,
+          'X-Elastic-Uncompressed-Request-Length' => anything
+        },
         :body => anything
       }
       if secure
         expected_manticore_opts = {
-          :headers => {"Content-Type" => "application/json", 'x-elastic-product-origin' => 'logstash-output-elasticsearch'},
+          :headers => {
+            "Content-Type" => "application/json",
+            'x-elastic-product-origin' => 'logstash-output-elasticsearch',
+            'X-Elastic-Event-Count' => anything,
+            'X-Elastic-Uncompressed-Request-Length' => anything
+          },
           :body => anything,
           :auth => {
             :user => user,
diff --git a/spec/unit/outputs/elasticsearch/http_client_spec.rb b/spec/unit/outputs/elasticsearch/http_client_spec.rb
index d4cee8f3..c2a93ac1 100644
--- a/spec/unit/outputs/elasticsearch/http_client_spec.rb
+++ b/spec/unit/outputs/elasticsearch/http_client_spec.rb
@@ -270,6 +270,83 @@
 
        end
      end
+    context "the 'user-agent' header" do
+      let(:pool) { double("pool") }
+      let(:compression_level) { 6 }
+      let(:base_options) { super().merge( :client_settings => {:compression_level => compression_level}) }
+      let(:actions) { [
+        ["index", {:_id=>nil, :_index=>"logstash"}, {"message_1"=> message_1}],
+        ["index", {:_id=>nil, :_index=>"logstash"}, {"message_2"=> message_2}],
+        ["index", {:_id=>nil, :_index=>"logstash"}, {"message_3"=> message_3}],
+      ]}
+      let(:message_1) { "hello" }
+      let(:message_2_size) { 1_000 }
+      let(:message_2) { SecureRandom.alphanumeric(message_2_size / 2 ) * 2 }
+      let(:message_3_size) { 1_000 }
+      let(:message_3) { "m" * message_3_size }
+      let(:messages_size) { message_1.size + message_2.size + message_3.size }
+      let(:action_overhead) { 42 + 16 + 2 } # header plus doc key size plus new line overhead per action
+
+      let(:response) do
+        response = double("response")
+        allow(response).to receive(:code).and_return(response)
+        allow(response).to receive(:body).and_return({"errors" => false}.to_json)
+        response
+      end
+
+      before(:each) do
+        subject.instance_variable_set("@pool", pool)
+      end
+
+      it "carries bulk request's uncompressed size" do
+        expect(pool).to receive(:post) do |path, params, body|
+          headers = params.fetch(:headers, {})
+          expect(headers["X-Elastic-Event-Count"]).to eq("3")
+          expect(headers["X-Elastic-Uncompressed-Request-Length"]).to eq (messages_size + (action_overhead * 3)).to_s
+        end.and_return(response)
+
+        subject.send(:bulk, actions)
+      end
+      context "without compression" do
+        let(:compression_level) { 0 }
+        it "carries bulk request's uncompressed size" do
+          expect(pool).to receive(:post) do |path, params, body|
+            headers = params.fetch(:headers, {})
+            expect(headers["X-Elastic-Event-Count"]).to eq("3")
+            expect(headers["X-Elastic-Uncompressed-Request-Length"]).to eq (messages_size + (action_overhead * 3)).to_s
+          end.and_return(response)
+          subject.send(:bulk, actions)
+        end
+      end
+
+      context "with compressed messages over 20MB" do
+        let(:message_2_size) { 21_000_000 }
+        it "carries bulk request's uncompressed size" do
+          # only the first, tiny, message is sent first
+          expect(pool).to receive(:post) do |path, params, body|
+            headers = params.fetch(:headers, {})
+            expect(headers["X-Elastic-Uncompressed-Request-Length"]).to eq (message_1.size + action_overhead).to_s
+            expect(headers["X-Elastic-Event-Count"]).to eq("1")
+          end.and_return(response)
+
+          # huge message_2 is sent afterwards alone
+          expect(pool).to receive(:post) do |path, params, body|
+            headers = params.fetch(:headers, {})
+            expect(headers["X-Elastic-Uncompressed-Request-Length"]).to eq (message_2.size + action_overhead).to_s
+            expect(headers["X-Elastic-Event-Count"]).to eq("1")
+          end.and_return(response)
+
+          # finally medium message_3 is sent alone as well
+          expect(pool).to receive(:post) do |path, params, body|
+            headers = params.fetch(:headers, {})
+            expect(headers["X-Elastic-Uncompressed-Request-Length"]).to eq (message_3.size + action_overhead).to_s
+            expect(headers["X-Elastic-Event-Count"]).to eq("1")
+          end.and_return(response)
+
+          subject.send(:bulk, actions)
+        end
+      end
+    end
   end
 
   describe "sniffing" do
diff --git a/spec/unit/outputs/elasticsearch_spec.rb b/spec/unit/outputs/elasticsearch_spec.rb
index ac713c5c..5d1d6628 100644
--- a/spec/unit/outputs/elasticsearch_spec.rb
+++ b/spec/unit/outputs/elasticsearch_spec.rb
@@ -770,7 +770,7 @@
       end
 
       before(:each) do
-        allow(subject.client).to receive(:bulk_send).with(instance_of(StringIO), instance_of(Array)) do |stream, actions|
+        allow(subject.client).to receive(:bulk_send).with(instance_of(StringIO), instance_of(Array), instance_of(Hash)) do |stream, actions, headers|
           expect( stream.string ).to include '"foo":"bar1"'
           expect( stream.string ).to include '"foo":"bar2"'
         end.and_return(bulk_response, {"errors"=>false}) # let's make it go away (second call) to not retry indefinitely