diff --git a/src/main/java/org/dataloader/BatchLoader.java b/src/main/java/org/dataloader/BatchLoader.java
index 2b0c3c5..14a902d 100644
--- a/src/main/java/org/dataloader/BatchLoader.java
+++ b/src/main/java/org/dataloader/BatchLoader.java
@@ -19,6 +19,7 @@
 import org.dataloader.annotations.PublicSpi;
 import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.List;
 import java.util.concurrent.CompletionStage;
@@ -77,7 +78,7 @@
 @FunctionalInterface
 @PublicSpi
 @NullMarked
-public interface BatchLoader<K, V> {
+public interface BatchLoader<K, V extends @Nullable Object> {
 
     /**
      * Called to batch load the provided keys and return a promise to a list of values.
diff --git a/src/main/java/org/dataloader/BatchLoaderWithContext.java b/src/main/java/org/dataloader/BatchLoaderWithContext.java
index eba26e4..fb6ff71 100644
--- a/src/main/java/org/dataloader/BatchLoaderWithContext.java
+++ b/src/main/java/org/dataloader/BatchLoaderWithContext.java
@@ -2,6 +2,7 @@
 
 import org.dataloader.annotations.PublicSpi;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.List;
 import java.util.concurrent.CompletionStage;
@@ -16,7 +17,7 @@
  */
 @PublicSpi
 @NullMarked
-public interface BatchLoaderWithContext<K, V> {
+public interface BatchLoaderWithContext<K, V extends @Nullable Object> {
     /**
      * Called to batch load the provided keys and return a promise to a list of values.  This default
      * version can be given an environment object to that maybe be useful during the call.  A typical use case
diff --git a/src/main/java/org/dataloader/BatchPublisher.java b/src/main/java/org/dataloader/BatchPublisher.java
index 943becf..360d8d2 100644
--- a/src/main/java/org/dataloader/BatchPublisher.java
+++ b/src/main/java/org/dataloader/BatchPublisher.java
@@ -23,7 +23,7 @@
  */
 @NullMarked
 @PublicSpi
-public interface BatchPublisher<K, V> {
+public interface BatchPublisher<K, V extends @Nullable Object> {
     /**
      * Called to batch the provided keys into a stream of values.  You <b>must</b> provide
      * the same number of values as there as keys, and they <b>must</b> be in the order of the keys.
diff --git a/src/main/java/org/dataloader/BatchPublisherWithContext.java b/src/main/java/org/dataloader/BatchPublisherWithContext.java
index 9ee010b..aafc2c9 100644
--- a/src/main/java/org/dataloader/BatchPublisherWithContext.java
+++ b/src/main/java/org/dataloader/BatchPublisherWithContext.java
@@ -2,6 +2,7 @@
 
 import org.dataloader.annotations.PublicSpi;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.reactivestreams.Subscriber;
 
 import java.util.List;
@@ -16,7 +17,7 @@
  */
 @NullMarked
 @PublicSpi
-public interface BatchPublisherWithContext<K, V> {
+public interface BatchPublisherWithContext<K, V extends @Nullable Object> {
     /**
      * Called to batch the provided keys into a stream of values.  You <b>must</b> provide
      * the same number of values as there as keys, and they <b>must</b> be in the order of the keys.
diff --git a/src/main/java/org/dataloader/MappedBatchLoader.java b/src/main/java/org/dataloader/MappedBatchLoader.java
index 1ad4c79..179d6a2 100644
--- a/src/main/java/org/dataloader/MappedBatchLoader.java
+++ b/src/main/java/org/dataloader/MappedBatchLoader.java
@@ -18,6 +18,7 @@
 
 import org.dataloader.annotations.PublicSpi;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.Map;
 import java.util.Set;
@@ -59,7 +60,7 @@
  */
 @PublicSpi
 @NullMarked
-public interface MappedBatchLoader<K, V> {
+public interface MappedBatchLoader<K, V extends @Nullable Object> {
 
     /**
      * Called to batch load the provided keys and return a promise to a map of values.
diff --git a/src/main/java/org/dataloader/MappedBatchLoaderWithContext.java b/src/main/java/org/dataloader/MappedBatchLoaderWithContext.java
index 9559260..9f342d4 100644
--- a/src/main/java/org/dataloader/MappedBatchLoaderWithContext.java
+++ b/src/main/java/org/dataloader/MappedBatchLoaderWithContext.java
@@ -18,6 +18,7 @@
 
 import org.dataloader.annotations.PublicSpi;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 
 import java.util.Map;
 import java.util.Set;
@@ -33,7 +34,7 @@
  */
 @PublicSpi
 @NullMarked
-public interface MappedBatchLoaderWithContext<K, V> {
+public interface MappedBatchLoaderWithContext<K, V extends @Nullable Object> {
     /**
      * Called to batch load the provided keys and return a promise to a map of values.
      *
diff --git a/src/main/java/org/dataloader/MappedBatchPublisher.java b/src/main/java/org/dataloader/MappedBatchPublisher.java
index 493401f..6637157 100644
--- a/src/main/java/org/dataloader/MappedBatchPublisher.java
+++ b/src/main/java/org/dataloader/MappedBatchPublisher.java
@@ -2,6 +2,7 @@
 
 import org.dataloader.annotations.PublicSpi;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.reactivestreams.Subscriber;
 
 import java.util.Map;
@@ -20,7 +21,7 @@
  */
 @PublicSpi
 @NullMarked
-public interface MappedBatchPublisher<K, V> {
+public interface MappedBatchPublisher<K, V extends @Nullable Object> {
     /**
      * Called to batch the provided keys into a stream of map entries of keys and values.
      * <p>
diff --git a/src/main/java/org/dataloader/MappedBatchPublisherWithContext.java b/src/main/java/org/dataloader/MappedBatchPublisherWithContext.java
index 7b862ca..dd8b5f9 100644
--- a/src/main/java/org/dataloader/MappedBatchPublisherWithContext.java
+++ b/src/main/java/org/dataloader/MappedBatchPublisherWithContext.java
@@ -2,6 +2,7 @@
 
 import org.dataloader.annotations.PublicSpi;
 import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
 import org.reactivestreams.Subscriber;
 
 import java.util.List;
@@ -17,7 +18,7 @@
  */
 @PublicSpi
 @NullMarked
-public interface MappedBatchPublisherWithContext<K, V> {
+public interface MappedBatchPublisherWithContext<K, V extends @Nullable Object> {
 
     /**
      * Called to batch the provided keys into a stream of map entries of keys and values.