diff --git a/Libraries/LibCore/AnonymousBuffer.cpp b/Libraries/LibCore/AnonymousBuffer.cpp
index 55004c7868f..f009ab0cefb 100644
--- a/Libraries/LibCore/AnonymousBuffer.cpp
+++ b/Libraries/LibCore/AnonymousBuffer.cpp
@@ -7,7 +7,6 @@
 #include <AK/Try.h>
 #include <LibCore/AnonymousBuffer.h>
 #include <LibCore/System.h>
-#include <LibIPC/File.h>
 #include <fcntl.h>
 #include <sys/mman.h>
 
diff --git a/Libraries/LibCore/AnonymousBuffer.h b/Libraries/LibCore/AnonymousBuffer.h
index f82e5837c6b..5604036fe6b 100644
--- a/Libraries/LibCore/AnonymousBuffer.h
+++ b/Libraries/LibCore/AnonymousBuffer.h
@@ -12,7 +12,6 @@
 #include <AK/RefCounted.h>
 #include <AK/RefPtr.h>
 #include <AK/Types.h>
-#include <LibIPC/Forward.h>
 
 namespace Core {
 
@@ -75,13 +74,3 @@ private:
 };
 
 }
-
-namespace IPC {
-
-template<>
-ErrorOr<void> encode(Encoder&, Core::AnonymousBuffer const&);
-
-template<>
-ErrorOr<Core::AnonymousBuffer> decode(Decoder&);
-
-}
diff --git a/Libraries/LibCore/DateTime.h b/Libraries/LibCore/DateTime.h
index e478ffe8090..3f5a8801155 100644
--- a/Libraries/LibCore/DateTime.h
+++ b/Libraries/LibCore/DateTime.h
@@ -8,7 +8,6 @@
 
 #include <AK/ByteString.h>
 #include <AK/StringView.h>
-#include <LibIPC/Forward.h>
 #include <time.h>
 
 namespace Core {
@@ -107,13 +106,3 @@ struct Formatter<Core::DateTime> : StandardFormatter {
 };
 
 }
-
-namespace IPC {
-
-template<>
-ErrorOr<void> encode(Encoder&, Core::DateTime const&);
-
-template<>
-ErrorOr<Core::DateTime> decode(Decoder&);
-
-}
diff --git a/Libraries/LibCore/Forward.h b/Libraries/LibCore/Forward.h
index d40a117254f..c78de9f96e1 100644
--- a/Libraries/LibCore/Forward.h
+++ b/Libraries/LibCore/Forward.h
@@ -49,6 +49,8 @@ class TimeZoneWatcher;
 class UDPServer;
 class UDPSocket;
 
+struct ProxyData;
+
 enum class TimerShouldFireWhenNotVisible;
 
 #ifdef AK_OS_MACH
diff --git a/Libraries/LibCore/Proxy.h b/Libraries/LibCore/Proxy.h
index 6ce883c6e7f..43fa7540aca 100644
--- a/Libraries/LibCore/Proxy.h
+++ b/Libraries/LibCore/Proxy.h
@@ -9,7 +9,6 @@
 #include <AK/Error.h>
 #include <AK/IPv4Address.h>
 #include <AK/Types.h>
-#include <LibIPC/Forward.h>
 #include <LibURL/URL.h>
 
 namespace Core {
@@ -48,13 +47,3 @@ struct ProxyData {
 };
 
 }
-
-namespace IPC {
-
-template<>
-ErrorOr<void> encode(Encoder&, Core::ProxyData const&);
-
-template<>
-ErrorOr<Core::ProxyData> decode(Decoder&);
-
-}
diff --git a/Libraries/LibIPC/Decoder.h b/Libraries/LibIPC/Decoder.h
index 7fa284c26a2..3666285990e 100644
--- a/Libraries/LibIPC/Decoder.h
+++ b/Libraries/LibIPC/Decoder.h
@@ -17,6 +17,7 @@
 #include <AK/Try.h>
 #include <AK/TypeList.h>
 #include <AK/Variant.h>
+#include <LibCore/Forward.h>
 #include <LibCore/SharedCircularQueue.h>
 #include <LibCore/Socket.h>
 #include <LibIPC/Concepts.h>
@@ -117,6 +118,15 @@ ErrorOr<File> decode(Decoder&);
 template<>
 ErrorOr<Empty> decode(Decoder&);
 
+template<>
+ErrorOr<Core::AnonymousBuffer> decode(Decoder&);
+
+template<>
+ErrorOr<Core::DateTime> decode(Decoder&);
+
+template<>
+ErrorOr<Core::ProxyData> decode(Decoder&);
+
 template<Concepts::Array T>
 ErrorOr<T> decode(Decoder& decoder)
 {
diff --git a/Libraries/LibIPC/Encoder.h b/Libraries/LibIPC/Encoder.h
index 04109393302..b4ebf037d09 100644
--- a/Libraries/LibIPC/Encoder.h
+++ b/Libraries/LibIPC/Encoder.h
@@ -11,6 +11,7 @@
 #include <AK/HashMap.h>
 #include <AK/StdLibExtras.h>
 #include <AK/Variant.h>
+#include <LibCore/Forward.h>
 #include <LibCore/SharedCircularQueue.h>
 #include <LibIPC/Concepts.h>
 #include <LibIPC/File.h>
@@ -116,6 +117,15 @@ ErrorOr<void> encode(Encoder&, File const&);
 template<>
 ErrorOr<void> encode(Encoder&, Empty const&);
 
+template<>
+ErrorOr<void> encode(Encoder&, Core::AnonymousBuffer const&);
+
+template<>
+ErrorOr<void> encode(Encoder&, Core::DateTime const&);
+
+template<>
+ErrorOr<void> encode(Encoder&, Core::ProxyData const&);
+
 template<Concepts::Span T>
 ErrorOr<void> encode(Encoder& encoder, T const& span)
 {