diff --git a/akka-http-core/src/main/scala/akka/http/model/parser/Base64Parsing.scala b/akka-http-core/src/main/scala/akka/http/model/parser/Base64Parsing.scala
index 60334c578a..46890850a4 100644
--- a/akka-http-core/src/main/scala/akka/http/model/parser/Base64Parsing.scala
+++ b/akka-http-core/src/main/scala/akka/http/model/parser/Base64Parsing.scala
@@ -23,7 +23,7 @@ import akka.parboiled2.util.Base64
 /**
  * Rules for parsing Base-64 encoded strings.
  */
-trait Base64Parsing { this: Parser ⇒
+private[parser] trait Base64Parsing { this: Parser ⇒
   import Base64Parsing._
 
   /**
diff --git a/akka-http-core/src/main/scala/akka/http/model/parser/StringBuilding.scala b/akka-http-core/src/main/scala/akka/http/model/parser/StringBuilding.scala
index 60b1c9ca5a..d3260b3771 100644
--- a/akka-http-core/src/main/scala/akka/http/model/parser/StringBuilding.scala
+++ b/akka-http-core/src/main/scala/akka/http/model/parser/StringBuilding.scala
@@ -24,7 +24,7 @@ import akka.parboiled2._
  *
  * Mixing this trait into your parser gives you a simple facility to support this.
  */
-trait StringBuilding { this: Parser ⇒
+private[parser] trait StringBuilding { this: Parser ⇒
   protected val sb = new java.lang.StringBuilder
 
   def clearSB(): Rule0 = rule { run(sb.setLength(0)) }