diff --git a/sdk/src/kalix.ts b/sdk/src/kalix.ts
index ce90d764a..f235f4d81 100644
--- a/sdk/src/kalix.ts
+++ b/sdk/src/kalix.ts
@@ -66,6 +66,11 @@ export interface KalixOptions {
    * Delay completing discovery until proxyPort has been set by the testkit.
    */
   delayDiscoveryUntilProxyPortSet?: boolean;
+
+  /**
+   * Channel settings.
+   */
+  channelSettings?: ChannelSettings;
 }
 
 /** @internal */
@@ -266,6 +271,20 @@ export interface PreStartSettings {
   identificationInfo?: discovery.IdentificationInfo;
 }
 
+/**
+ * Settings for the gRPC channel used to communicate with the Kalix proxy
+ */
+export interface ChannelSettings {
+  /**
+   * The maximum number of bytes a gRPC message may be when receiving
+   */
+  maxReceiveMessageLength?: number;
+  /**
+   * The maximum number of bytes a gRPC message may be when sending
+   */
+  maxSendMessageLength?: number;
+}
+
 /**
  * Kalix Entity.
  *
@@ -430,7 +449,9 @@ export class Kalix {
       );
     }
 
-    this.server = new grpc.Server();
+    this.server = new grpc.Server(
+      this.channelSettingsToGrpcChannelOptions(options?.channelSettings),
+    );
   }
 
   /**
@@ -780,6 +801,21 @@ export class Kalix {
     return spec;
   }
 
+  private channelSettingsToGrpcChannelOptions(
+    settings?: ChannelSettings,
+  ): grpc.ChannelOptions {
+    const opts = {
+      'grpc.max_receive_message_length': settings?.maxReceiveMessageLength,
+      'grpc.max_send_message_length': settings?.maxSendMessageLength,
+    };
+    if (!opts['grpc.max_receive_message_length']) {
+      // Default to 12 mb
+      opts['grpc.max_receive_message_length'] = 12 * 1024 * 1024;
+    }
+
+    return opts;
+  }
+
   private proxyTerminatedLogic() {
     this.proxyHasTerminated = true;
     if (this.waitingForProxyTermination) {
diff --git a/tck/package.json b/tck/package.json
index 3ba49e40a..62248f2c3 100644
--- a/tck/package.json
+++ b/tck/package.json
@@ -11,7 +11,8 @@
   },
   "devDependencies": {
     "testcontainers": "7.10.0",
-    "typescript": "4.3.4"
+    "typescript": "4.3.4",
+    "protobufjs": "6.11.3"
   },
   "scripts": {
     "clean": "rimraf ./proto ./generated ./dist",