diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java b/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java
index 546f097b0..55ecde835 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java
@@ -40,6 +40,7 @@ import jakarta.servlet.Filter;
 import jakarta.servlet.ServletRegistration;
 import java.io.ByteArrayInputStream;
 import java.io.FileInputStream;
+import java.net.URI;
 import java.net.http.HttpClient;
 import java.nio.charset.StandardCharsets;
 import java.security.KeyStore;
@@ -411,6 +412,7 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
     final S3AsyncClient asyncCdnS3Client = S3AsyncClient.builder()
         .credentialsProvider(cdnCredentialsProvider)
         .region(Region.of(config.getCdnConfiguration().region()))
+        .endpointOverride(config.getCdnConfiguration().endpointOverride())
         .build();
 
     BlockingQueue<Runnable> messageDeletionQueue = new LinkedBlockingQueue<>();
@@ -442,6 +444,7 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
     S3AsyncClient asyncKeysS3Client = S3AsyncClient.builder()
         .credentialsProvider(awsCredentialsProvider)
         .region(Region.of(config.getPagedSingleUseKEMPreKeyStore().region()))
+        .endpointOverride(config.getPagedSingleUseKEMPreKeyStore().endpointOverride())
         .build();
     KeysManager keysManager = new KeysManager(
         new SingleUseECPreKeyStore(dynamoDbAsyncClient, config.getDynamoDbTables().getEcKeys().getTableName()),
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/configuration/CdnConfiguration.java b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/CdnConfiguration.java
index e2428291a..a88609c7d 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/configuration/CdnConfiguration.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/CdnConfiguration.java
@@ -8,8 +8,11 @@ package org.whispersystems.textsecuregcm.configuration;
 import jakarta.validation.Valid;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.NotNull;
+import javax.annotation.Nullable;
+import java.net.URI;
 
 public record CdnConfiguration(@NotNull @Valid StaticAwsCredentialsFactory credentials,
                                @NotBlank String bucket,
-                               @NotBlank String region) {
+                               @NotBlank String region,
+                               @Nullable URI endpointOverride) {
 }
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/configuration/PagedSingleUseKEMPreKeyStoreConfiguration.java b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/PagedSingleUseKEMPreKeyStoreConfiguration.java
index 24d7b979a..430d86d7d 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/configuration/PagedSingleUseKEMPreKeyStoreConfiguration.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/configuration/PagedSingleUseKEMPreKeyStoreConfiguration.java
@@ -5,11 +5,12 @@
 
 package org.whispersystems.textsecuregcm.configuration;
 
-import jakarta.validation.Valid;
 import jakarta.validation.constraints.NotBlank;
-import jakarta.validation.constraints.NotNull;
+import javax.annotation.Nullable;
+import java.net.URI;
 
 public record PagedSingleUseKEMPreKeyStoreConfiguration(
     @NotBlank String bucket,
-    @NotBlank String region) {
+    @NotBlank String region,
+    @Nullable URI endpointOverride) {
 }