diff --git a/.dlc.json b/.dlc.json
new file mode 100644
index 0000000000000000000000000000000000000000..f2b124ebc1a9637a3e039c6214bc628e1cdf6a1e
--- /dev/null
+++ b/.dlc.json
@@ -0,0 +1,18 @@
+{
+  "ignorePatterns": [
+    {
+      "pattern": "^http://localhost"
+    },
+    {
+      "pattern": "^https://github.com/apache/skywalking/blob/master/changes/changes-x.y.z.md$"
+    }
+  ],
+  "timeout": "10s",
+  "retryOn429": true,
+  "retryCount": 10,
+  "fallbackRetryDelay": "1000s",
+  "aliveStatusCodes": [
+    200,
+    401
+  ]
+}
diff --git a/.github/actions/skip/action.yml b/.github/actions/skip/action.yml
index 44536a81c24114a5353d1b6f060c6a04fa26e620..2e6de66d10f8d9d58fe7276d9f6642f320042918 100644
--- a/.github/actions/skip/action.yml
+++ b/.github/actions/skip/action.yml
@@ -28,6 +28,8 @@ inputs:
       "*.md"
       "skywalking-ui"
       ".asf.yaml"
+      ".dlc.yaml"
+      ".licenserc.yaml"
 runs:
   using: "composite"
   steps:
diff --git a/.github/workflows/dead-link-checker.yaml b/.github/workflows/dead-link-checker.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..d58181030756b2a82395eaa59f1032f6b17efce1
--- /dev/null
+++ b/.github/workflows/dead-link-checker.yaml
@@ -0,0 +1,32 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+name: Dead Link Checker
+
+on:
+  pull_request:
+
+jobs:
+  CheckDeadLinks:
+    runs-on: ubuntu-18.04
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@v2
+      - run: sudo npm install -g markdown-link-check
+      - run: |
+          for file in $(find . -name "*.md"); do
+            markdown-link-check -c .dlc.json -q "$file"
+          done
diff --git a/CODE_OF_CONDUCT.md b/CODE_OF_CONDUCT.md
index 220f9b4cc23a381cb467273e3b471b2ea36cb852..e45fd4af1b138b2267bb3ce41d91912599fe00d8 100644
--- a/CODE_OF_CONDUCT.md
+++ b/CODE_OF_CONDUCT.md
@@ -71,7 +71,7 @@ This statement thanks the following, on which it draws for content and inspirati
 
 * [CouchDB Project Code of conduct](http://couchdb.apache.org/conduct.html)
 * [Fedora Project Code of Conduct](http://fedoraproject.org/code-of-conduct)
-* [Speak Up! Code of Conduct](http://speakup.io/coc.html)
+* [Speak Up! Code of Conduct](https://code-of-conduct.roche.com/en/speak-up.html)
 * [Django Code of Conduct](https://www.djangoproject.com/conduct/)
 * [Debian Code of Conduct](http://www.debian.org/vote/2014/vote_002)
 * [Twitter Open Source Code of Conduct](https://github.com/twitter/code-of-conduct/blob/master/code-of-conduct.md)
diff --git a/README.md b/README.md
index 4cfe97c82c328a0abb7793c861a1128ac0e7dba7..c275be4269682b44b340c08d924ef6d4dd9d3271 100644
--- a/README.md
+++ b/README.md
@@ -101,4 +101,4 @@ SkyWalking enriches the <a href="https://landscape.cncf.io/landscape=observabili
 </p>
 
 # License
-[Apache 2.0 License.](/LICENSE)
+[Apache 2.0 License.](LICENSE)
diff --git a/changes/changes-8.4.0.md b/changes/changes-8.4.0.md
index ab2da632fb40dc75a76509b37b12116a1950886b..22c6dea743c937b0ccc736ae50fe619c0555572e 100644
--- a/changes/changes-8.4.0.md
+++ b/changes/changes-8.4.0.md
@@ -61,7 +61,7 @@ Release Notes.
 * Improve query performance in storage-influxdb-plugin.
 * Fix the uuid field in GRPCConfigWatcherRegister is not updated.
 * Support Envoy {AccessLog,Metrics}Service API V3.
-* Adopt the [MAL](docs/en/concepts-and-designs/mal.md) in Envoy metrics service analyzer.
+* Adopt the [MAL](../docs/en/concepts-and-designs/mal.md) in Envoy metrics service analyzer.
 * Fix the priority setting doesn't work of the ALS analyzers.
 * Fix bug that `endpoint-name-grouping.yml` is not customizable in Dockerized case.
 * Fix bug that istio version metric type on UI template mismatches the otel rule.
diff --git a/docs/en/concepts-and-designs/probe-introduction.md b/docs/en/concepts-and-designs/probe-introduction.md
index 7e4ed470807d81f69173e3127e5ea6d81cbbdd35..38b85fe74f284ee0dbf725a481dc45292a7956e1 100644
--- a/docs/en/concepts-and-designs/probe-introduction.md
+++ b/docs/en/concepts-and-designs/probe-introduction.md
@@ -33,6 +33,6 @@ like logs, just save them, and build the links between traces and metrics, like
 
 ## What is next?
 - Learn the SkyWalking supported probes in [Service auto instrument agent](service-agent.md), [Manual instrument SDK](manual-sdk.md),
-[Service Mesh probe](service-mesh-probe.md) and [Zipkin receiver](trace-receiver.md).
+[Service Mesh probe](service-mesh-probe.md) and [Zipkin receiver](../setup/backend/backend-receivers.md#zipkin-receiver).
 - After understand the probe, read [backend overview](backend-overview.md) for understanding analysis and persistence.
 
diff --git a/docs/en/guides/Java-Plugin-Development-Guide.md b/docs/en/guides/Java-Plugin-Development-Guide.md
index e1b2b265c2727d936ad5ea0657d404fb8093d525..d6c27ed061005fd6a2fd4a2f437d72a79a6de47a 100644
--- a/docs/en/guides/Java-Plugin-Development-Guide.md
+++ b/docs/en/guides/Java-Plugin-Development-Guide.md
@@ -321,7 +321,7 @@ tomcat-7.x/8.x=TomcatInstrumentation
      return witnessMethodList;
    }
    ```
-   For more example, see [WitnessTest.java](/apm-sniffer/apm-agent-core/src/test/java/org/apache/skywalking/apm/agent/core/plugin/witness/WitnessTest.java)
+   For more example, see [WitnessTest.java](../../../apm-sniffer/apm-agent-core/src/test/java/org/apache/skywalking/apm/agent/core/plugin/witness/WitnessTest.java)
 
    
 
diff --git a/docs/en/protocols/Browser-HTTP-API-Protocol.md b/docs/en/protocols/Browser-HTTP-API-Protocol.md
index f33b99b27146131479b39f771c04b3f0ad94006b..245711f52fd40730dea1d3e28bda203867a2f82c 100644
--- a/docs/en/protocols/Browser-HTTP-API-Protocol.md
+++ b/docs/en/protocols/Browser-HTTP-API-Protocol.md
@@ -41,7 +41,7 @@ Http Status: 204
 
 ## Error Log Report
 
-Detail information about data format can be found in [BrowserPerf.proto](https://github.com/apache/skywalking-data-collect-protocol/blob/master/Browser/BrowserPerf.proto).
+Detail information about data format can be found in [BrowserPerf.proto](https://github.com/apache/skywalking-data-collect-protocol/blob/master/browser/BrowserPerf.proto).
 
 ### POST http://localhost:12800/browser/errorLogs
 
diff --git a/docs/en/protocols/JVM-Protocol.md b/docs/en/protocols/JVM-Protocol.md
index 48a3063fb5befb9921086313e9a9ea97dadaf25a..36214d4228871ed3aecbe7e2d1c5913a0a8ad4f5 100644
--- a/docs/en/protocols/JVM-Protocol.md
+++ b/docs/en/protocols/JVM-Protocol.md
@@ -2,4 +2,4 @@
 ## Abstract
 Uplink the JVM metrics, including PermSize, HeapSize, CPU, Memory, etc., every second.
 
-[gRPC service define](https://github.com/apache/skywalking-data-collect-protocol/blob/v2.0/JVMMetricsService.proto)
\ No newline at end of file
+[gRPC service define](https://github.com/apache/skywalking-data-collect-protocol/blob/master/language-agent/JVMMetric.proto)
diff --git a/docs/en/setup/envoy/metrics_service_setting.md b/docs/en/setup/envoy/metrics_service_setting.md
index 438acdf6e9e0b588e134285f176dbc4566924d85..bc3babcf57a3fd7cf4d8f7b57f2f2347d43d51d3 100644
--- a/docs/en/setup/envoy/metrics_service_setting.md
+++ b/docs/en/setup/envoy/metrics_service_setting.md
@@ -50,7 +50,7 @@ static_resources:
 
 A more complete static configuration, can be observed [here](config.yaml).
 
-Note that Envoy can also be configured dynamically through [xDS Protocol](https://github.com/envoyproxy/data-plane-api/blob/master/XDS_PROTOCOL.md).
+Note that Envoy can also be configured dynamically through [xDS Protocol](https://github.com/envoyproxy/data-plane-api/blob/main/xds_protocol.rst).
 
 As mentioned above, SkyWalking also builds the topology of services from the metrics, this is because Envoy also carries the service metadata along with the metrics, to feed the Envoy such metadata, another configuration part is as follows:
 
@@ -65,7 +65,7 @@ node:
 
 ## Configure Envoy to send metrics to SkyWalking with Istio
 
-Typically, Envoy can be also used under Istio's control, where the configurations are much more simple because Istio composes the configurations for you and sends them to Envoy via [xDS Protocol](https://github.com/envoyproxy/data-plane-api/blob/master/XDS_PROTOCOL.md).
+Typically, Envoy can be also used under Istio's control, where the configurations are much more simple because Istio composes the configurations for you and sends them to Envoy via [xDS Protocol](https://github.com/envoyproxy/data-plane-api/blob/master/xds_protocol.rst).
 Istio also automatically injects the metadata such as service name and instance name into the bootstrap configurations.
 
 Under this circumstance, emitting the metrics to SyWalking is as simple as adding the option `--set meshConfig.defaultConfig.envoyMetricsService.address=<skywalking.address.port.11800>` to Istio install command, for example:
diff --git a/docs/en/setup/service-agent/java-agent/README.md b/docs/en/setup/service-agent/java-agent/README.md
index c20d40e15c4fac94dec565f778361a9d4c30f4d1..134e21f8d9d46bd65288e40e64a647049d7e40a1 100755
--- a/docs/en/setup/service-agent/java-agent/README.md
+++ b/docs/en/setup/service-agent/java-agent/README.md
@@ -134,7 +134,7 @@ property key | Description | Default |
 `plugin.solrj.trace_statement`|If true, trace all the query parameters(include deleteByIds and deleteByQuery) in Solr query request, default is false.|`false`|
 `plugin.solrj.trace_ops_params`|If true, trace all the operation parameters in Solr request, default is false.|`false`|
 `plugin.light4j.trace_handler_chain`|If true, trace all middleware/business handlers that are part of the Light4J handler chain for a request.|false|
-`plugin.opgroup.*`|Support operation name customize group rules in different plugins. Read [Group rule supported plugins](op_name_group_rule.md)|Not set|
+`plugin.opgroup.*`|Support operation name customize group rules in different plugins. Read [Group rule supported plugins](../../backend/endpoint-grouping-rules.md)|Not set|
 `plugin.springtransaction.simplify_transaction_definition_name`|If true, the transaction definition name will be simplified.|false|
 `plugin.jdkthreading.threading_class_prefixes` | Threading classes (`java.lang.Runnable` and `java.util.concurrent.Callable`) and their subclasses, including anonymous inner classes whose name match any one of the `THREADING_CLASS_PREFIXES` (splitted by `,`) will be instrumented, make sure to only specify as narrow prefixes as what you're expecting to instrument, (`java.` and `javax.` will be ignored due to safety issues) | Not set |
 `plugin.tomcat.collect_http_params`| This config item controls that whether the Tomcat plugin should collect the parameters of the request. Also, activate implicitly in the profiled trace. | `false` |
diff --git a/docs/en/setup/service-agent/java-agent/Supported-list.md b/docs/en/setup/service-agent/java-agent/Supported-list.md
index 70f6b2fee32616c8b826015433c9d315c43ef02f..e9efea2d7edfb2c7621472c189622564a9ab9916 100644
--- a/docs/en/setup/service-agent/java-agent/Supported-list.md
+++ b/docs/en/setup/service-agent/java-agent/Supported-list.md
@@ -26,7 +26,7 @@ metrics based on the tracing data.
   * [Apache httpcomponent HttpClient](http://hc.apache.org/) 2.0 -> 3.1, 4.2, 4.3
   * [Spring RestTemplete](https://github.com/spring-projects/spring-framework) 4.x
   * [Jetty Client](http://www.eclipse.org/jetty/) 9
-  * [Apache httpcomponent AsyncClient](https://hc.apache.org/httpcomponents-asyncclient-dev/) 4.x
+  * [Apache httpcomponent AsyncClient](https://hc.apache.org/httpcomponents-asyncclient-4.1.x/) 4.x
   * [AsyncHttpClient](https://github.com/AsyncHttpClient/async-http-client) 2.x
   * JRE HttpURLConnection (Optional²)
 * HTTP Gateway