diff --git a/bikeshed/src/com/google/gwt/requestfactory/server/DefaultSecurityProvider.java b/bikeshed/src/com/google/gwt/requestfactory/server/DefaultSecurityProvider.java
index 4b92239..a063474 100644
--- a/bikeshed/src/com/google/gwt/requestfactory/server/DefaultSecurityProvider.java
+++ b/bikeshed/src/com/google/gwt/requestfactory/server/DefaultSecurityProvider.java
@@ -18,6 +18,11 @@
 import com.google.gwt.requestfactory.shared.Service;
 
 /**
+ * <p>
+ * <span style="color:red">Experimental API: This class is still under rapid
+ * development, and is very likely to be deleted. Use it at your own risk.
+ * </span>
+ * </p>
  * A security provider that enforces {@link com.google.gwt.requestfactory.shared.Service}
  * annotations.
  */
diff --git a/bikeshed/src/com/google/gwt/requestfactory/server/OperationRegistry.java b/bikeshed/src/com/google/gwt/requestfactory/server/OperationRegistry.java
index ef8a538..5eb8917 100644
--- a/bikeshed/src/com/google/gwt/requestfactory/server/OperationRegistry.java
+++ b/bikeshed/src/com/google/gwt/requestfactory/server/OperationRegistry.java
@@ -18,6 +18,11 @@
 import com.google.gwt.requestfactory.shared.RequestFactory;
 
 /**
+ * <p>
+ * <span style="color:red">Experimental API: This class is still under rapid
+ * development, and is very likely to be deleted. Use it at your own risk.
+ * </span>
+ * </p>
  * Maps operation name to {RequestDefinition}.
  */
 public interface OperationRegistry {
diff --git a/bikeshed/src/com/google/gwt/requestfactory/server/ReflectionBasedOperationRegistry.java b/bikeshed/src/com/google/gwt/requestfactory/server/ReflectionBasedOperationRegistry.java
index 529e7c0..e96a2c7 100644
--- a/bikeshed/src/com/google/gwt/requestfactory/server/ReflectionBasedOperationRegistry.java
+++ b/bikeshed/src/com/google/gwt/requestfactory/server/ReflectionBasedOperationRegistry.java
@@ -27,6 +27,11 @@
 import java.util.List;
 
 /**
+ * <p>
+ * <span style="color:red">Experimental API: This class is still under rapid
+ * development, and is very likely to be deleted. Use it at your own risk.
+ * </span>
+ * </p>
  * OperationRegistry which uses the operation name as a convention for
  * reflection to a method on a class, and returns an appropriate {@link
  * com.google.gwt.requestfactory.shared.RequestFactory.RequestDefinition}.
diff --git a/bikeshed/src/com/google/gwt/requestfactory/server/RequestSecurityProvider.java b/bikeshed/src/com/google/gwt/requestfactory/server/RequestSecurityProvider.java
index e95ad31..232eb85 100644
--- a/bikeshed/src/com/google/gwt/requestfactory/server/RequestSecurityProvider.java
+++ b/bikeshed/src/com/google/gwt/requestfactory/server/RequestSecurityProvider.java
@@ -16,6 +16,11 @@
 package com.google.gwt.requestfactory.server;
 
 /**
+ * <p>
+ * <span style="color:red">Experimental API: This class is still under rapid
+ * development, and is very likely to be deleted. Use it at your own risk.
+ * </span>
+ * </p>
  * Enforces security policy for operations and classes, as well as permitting
  * request obfuscation.
  */
diff --git a/bikeshed/src/com/google/gwt/requestfactory/shared/Service.java b/bikeshed/src/com/google/gwt/requestfactory/shared/Service.java
index 59f2cf5..1baddc0 100644
--- a/bikeshed/src/com/google/gwt/requestfactory/shared/Service.java
+++ b/bikeshed/src/com/google/gwt/requestfactory/shared/Service.java
@@ -21,6 +21,11 @@
 import java.lang.annotation.Target;
 
 /**
+ * <p>
+ * <span style="color:red">Experimental API: This class is still under rapid
+ * development, and is very likely to be deleted. Use it at your own risk.
+ * </span>
+ * </p>
  * Annotation on Request classes specifying the server side implementations that
  * back them.
  */