diff --git a/docs/index.bs b/docs/index.bs
index 0a280725..c681b8d4 100644
--- a/docs/index.bs
+++ b/docs/index.bs
@@ -1606,6 +1606,10 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
 
     Note: {{RouterCondition/_or}} and {{RouterCondition/not}} might have the other {{RouterCondition/_or}} or {{RouterCondition/not}} inside. To avoid spending much resources by the nested condition or performance penalty on evaluation, depth of such nested conditions can be limited.
 
+    A <dfn export id="dfn-count-router-condition-result">count router condition result</dfn> is a [=struct=] that consists of:
+      * A <dfn export id="dfn-count-router-condition-result-total-count" for="count router condition result">total count</dfn> (a number).
+      * A <dfn export id="dfn-dfn-count-router-condition-result-depth" for="count router condition result">depth</dfn> (a number).
+
     <section>
       <h4 id="register-router-method">{{InstallEvent/addRoutes(rules)|event.addRoutes(rules)}}</h4>
 
@@ -1620,6 +1624,7 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
             1. If running the [=Verify Router Condition=] algorithm with |rule|["{{RouterRule/condition}}"] and |serviceWorker| returns false, return [=a promise rejected with=] a {{TypeError}}.
             1. Append |rule| to |routerRules|.
         1. If |routerRules| [=list/contains=] a {{RouterRule}} whose {{RouterRule/source}} is either of "{{RouterSourceEnum/fetch-event}}" or "{{RouterSourceEnum/race-network-and-fetch-handler}}", and |serviceWorker|'s [=set of event types to handle=] does not [=set/contain=] {{ServiceWorkerGlobalScope/fetch!!event}}, return [=a promise rejected with=] a {{TypeError}}.
+        1. If running the [=Check Router Registration Limit=] with |serviceWorker| returns false, return [=a promise rejected with=] a {{TypeError}}.
         1. Set |serviceWorker|'s [=service worker/list of router rules=] to |routerRules|.
         1. Return [=a promise resolved with=] undefined.
 
@@ -3409,14 +3414,14 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
               Note: To limit the resource usage and a condition evaluation time, |orConditions|'s [=list/size=] can be limited.
  
           1. For each |orCondition| of |orConditions|:
-              1. If running the [=Verify Router Condition=] algorithm with |orCondition| and |serviceWorker| returns false, return false.
+              1. If running the [=Verify Router Condition=] algorithm with |orCondition| and |serviceWorker| and |registeredRuleCount| returns false, return false.
           1. Set |hasCondition| to true.
       1. If |condition|["{{RouterCondition/not}}"] [=map/exists=], then:
           1. If |hasCondition| is true, return false.
 
               Note: For ease of understanding the router rule, the "not" condition is mutually exclusive with other conditions.
 
-          1. If running the [=Verify Router Condition=] algorithm with |condition|["{{RouterCondition/not}}"] and |serviceWorker| returns false, return false.
+          1. If running the [=Verify Router Condition=] algorithm with |condition|["{{RouterCondition/not}}"] and |serviceWorker| and |registeredRuleCount| returns false, return false.
           1. Set |hasCondition| to true.
       1. If |hasCondition| is true, then:
           1. Increament |serviceWorker|'s [=service worker/router rule count=] by one.
@@ -3468,6 +3473,53 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
           1. Return true.
   </section>
 
+  <section algorithm>
+    <h3 id="check-router-registration-limit"><dfn>Check Router Registration Limit</dfn></h3>
+      : Input
+      :: |serviceWorker|, a [=/service worker=]
+      : Output
+      :: a boolean
+
+      1. Let |result| be a [=count router condition result=].
+      1. Set |result|'s [=count router condition result/total count=] to 0.
+      1. Set |result|'s [=count router condition result/depth=] to 1.
+      1. Let |maxRuleCount| be 1024.
+      1. Let |maxDepth| be 10.
+      1. [=list/For each=] |rule| of |serviceWorker|'s [=service worker/list of router rules=]:
+          1. Let |currentResult| be the result of running [=Count Router Inner Conditions=] with |rule|["{{RouterRule/condition}}"], |result|, |maxRuleCount|, and |maxDepth|.
+          1. If |currentResult|'s [=count router condition result/total count=] exceeds |maxRuleCount|, return false.
+          1. If |currentResult|'s [=count router condition result/depth=] exceeds |maxDepth|, return false.
+          1. Set |result|'s [=count router condition result/total count=] to |currentResult|'s [=count router condition result/total count=].
+      1. return true.
+  </section> 
+
+   <section algorithm>
+    <h3 id="count-router-inner-conditions"><dfn>Count Router Inner Conditions</dfn></h3>
+      : Input
+      :: |condition|, a {{RouterCondition}}
+      :: |result|, a [=count router condition result=]
+      :: |maxCount|, a number
+      :: |maxDepth|, a number
+      : Output
+      :: |result|, a [=count router condition result=]
+
+      1. Increment |result|'s [=count router condition result/total count=] by one.
+      1. If |result|'s [=count router condition result/total count=] exceeds |maxCount|, return |result|.
+      1. If |result|'s [=count router condition result/depth=] exceeds |maxDepth|, return |result|.
+      1. If |condition|["{{RouterCondition/_or}}"] [=map/exists=], then:
+          1. Increment |result|'s [=count router condition result/depth=] by one.
+          1. For each |orCondition| of |condition|["{{RouterCondition/_or}}"]:
+              1. Set |result| to be the result of running [=Count Router Inner Conditions=] with |orCondition|, |result|, |maxCount|, and |maxDepth|.
+              1. If |result|'s [=count router condition result/total count=] exceeds |maxCount|, return |result|.
+              1. If |result|'s [=count router condition result/depth=] exceeds |maxDepth|, return |result|.
+      1. Else if |condition|["{{RouterCondition/not}}"] [=map/exists=], then:
+          1. Increment |result|'s [=count router condition result/depth=] by one.
+          1. Let |result| be the result of running [=Count Router Inner Conditions=] with |condition|["{{RouterCondition/not}}"], |result|, |maxCount|, and |maxDepth|.
+          1. If |result|'s [=count router condition result/total count=] exceeds |maxCount|, return |result|.
+          1. If |result|'s [=count router condition result/depth=] exceeds |maxDepth|, return |result|. 
+      1. Return |result|.
+  </section>
+
   <section algorithm>
     <h3 id="get-router-source-algorithm"><dfn>Get Router Source</dfn></h3>
       : Input