diff --git a/src/Microsoft.AspNetCore.SystemWebAdapters.Abstractions/SessionState/Serialization/ISessionSerializer.cs b/src/Services/SessionState/ISessionSerializer.cs
similarity index 92%
rename from src/Microsoft.AspNetCore.SystemWebAdapters.Abstractions/SessionState/Serialization/ISessionSerializer.cs
rename to src/Services/SessionState/ISessionSerializer.cs
index 75f79a71c..534d87054 100644
--- a/src/Microsoft.AspNetCore.SystemWebAdapters.Abstractions/SessionState/Serialization/ISessionSerializer.cs
+++ b/src/Services/SessionState/ISessionSerializer.cs
@@ -7,7 +7,7 @@
 
 namespace Microsoft.AspNetCore.SystemWebAdapters.SessionState.Serialization;
 
-public interface ISessionSerializer
+internal interface ISessionSerializer
 {
     Task<ISessionState?> DeserializeAsync(Stream stream, CancellationToken token);