diff --git a/src/implementation/Client/GRPCClient/GRPCClient.ts b/src/implementation/Client/GRPCClient/GRPCClient.ts
index 340f8474..0e083eeb 100644
--- a/src/implementation/Client/GRPCClient/GRPCClient.ts
+++ b/src/implementation/Client/GRPCClient/GRPCClient.ts
@@ -55,7 +55,9 @@ export default class GRPCClient implements IClient {
       interceptors.push(this.generateInterceptor());
     }
 
-    const baseUrl = `${this.daprEndpoint.tls ? "https" : "http"}://${this.daprEndpoint.hostname}:${this.daprEndpoint.port}`;
+    const baseUrl = `${this.daprEndpoint.tls ? "https" : "http"}://${this.daprEndpoint.hostname}:${
+      this.daprEndpoint.port
+    }`;
     this.logger.info(`Opening connection to ${this.options.daprHost}:${this.options.daprPort}`);
 
     const transport = createGrpcTransport({
diff --git a/src/implementation/Client/GRPCClient/invoker.ts b/src/implementation/Client/GRPCClient/invoker.ts
index f8d6045d..82b571c2 100644
--- a/src/implementation/Client/GRPCClient/invoker.ts
+++ b/src/implementation/Client/GRPCClient/invoker.ts
@@ -43,6 +43,13 @@ export default class GRPCClientInvoker implements IClientInvoker {
     });
 
     const { serializedData, contentType } = SerializerUtil.serializeGrpc(data);
+    const maxBytes = (this.client.options.maxBodySizeMb ?? 4) * 1024 * 1024;
+
+    const payloadSize = serializedData.length;
+
+    if (payloadSize > maxBytes) {
+      throw new Error(`Payload size ${payloadSize} exceeds maxBodySizeMb (${maxBytes})`);
+    }
     const msgSerialized = create(AnySchema, { value: serializedData });
 
     const msgInvoke = create(InvokeRequestSchema, {
diff --git a/test/e2e/grpc/server.test.ts b/test/e2e/grpc/server.test.ts
index 769de1db..989beb2c 100644
--- a/test/e2e/grpc/server.test.ts
+++ b/test/e2e/grpc/server.test.ts
@@ -25,7 +25,7 @@ import {
 } from "../helpers/containers";
 
 const serverHost = "127.0.0.1";
-const serverPort = "3001";
+const serverPort = "4001";
 const daprAppId = "test-suite-grpc-server";
 
 describe("grpc/server", () => {
@@ -43,10 +43,7 @@ describe("grpc/server", () => {
 
   beforeAll(async () => {
     network = await new Network().start();
-    [redisContainer, mqttContainer] = await Promise.all([
-      startRedisContainer(network),
-      startMqttContainer(network),
-    ]);
+    [redisContainer, mqttContainer] = await Promise.all([startRedisContainer(network), startMqttContainer(network)]);
 
     // The Dapr container calls back to the gRPC app server on the host.
     await TestContainers.exposeHostPorts(parseInt(serverPort));
@@ -83,7 +80,7 @@ describe("grpc/server", () => {
       .withNetwork(network)
       .withAppId(daprAppId)
       .withAppPort(parseInt(serverPort))
-      .withAppChannelAddress("host.testcontainers.internal")
+      .withAppChannelAddress(process.env.CI ? "localhost" : "host.docker.internal")
       .withDaprLogLevel("info")
       .withMaxRequestSizeMb(10)
       .withComponent(buildBindingMqttComponent())
@@ -167,20 +164,51 @@ describe("grpc/server", () => {
     );
 
     it("should be able to receive payloads larger than 4 MB", async () => {
-      await new Promise((resolve, _reject) => setTimeout(resolve, 1000));
-      // 5 MB is above Dapr's default 4 MB limit but below our 10 MB sidecar limit.
       const payload = new Uint8Array(5 * 1024 * 1024);
 
+      const res = await server.client.invoker.invoke(daprAppId, "test-invoker", HttpMethod.POST, payload);
+
+      expect(res).toBeDefined();
+      expect(mockInvoker).toHaveBeenCalled();
+    });
+
+    it("should fail for payload > 4MB when maxBodySizeMb is NOT set (default behavior)", async () => {
+      // Create a NEW container WITHOUT override
+      const defaultDaprContainer = await new DaprGrpcAppContainer()
+        .withNetwork(network)
+        .withAppId(daprAppId)
+        .withAppPort(parseInt(serverPort))
+        .withAppChannelAddress("host.docker.internal")
+        .withDaprLogLevel("info")
+        // ❌ NO .withMaxRequestSizeMb()
+        .withComponent(buildBindingMqttComponent())
+        .withComponent(buildBindingRedisComponent())
+        .withComponent(buildConfigRedisComponent())
+        .start();
+
+      const client = new DaprClient({
+        daprHost: defaultDaprContainer.getHost(),
+        daprPort: defaultDaprContainer.getGrpcPort().toString(),
+        communicationProtocol: CommunicationProtocolEnum.GRPC,
+      });
+
+      await client.start();
+      await new Promise((resolve) => setTimeout(resolve, 2000));
+
+      const payload = new Uint8Array(5 * 1024 * 1024); // 5MB (>4MB default)
+
+      let error: any;
       try {
-        const res = await server.client.invoker.invoke(daprAppId, "test-invoker", HttpMethod.POST, payload);
-        console.log(res);
-      } catch (e) {
-        console.log(e);
+        await client.invoker.invoke(daprAppId, "test-invoker", HttpMethod.POST, payload);
+      } catch (e: any) {
+        error = e;
       }
 
-      // Delay a bit for event to arrive
-      await new Promise((resolve, _reject) => setTimeout(resolve, 250));
-    });
+      expect(error.message).toBeDefined();
+
+      await client.stop().catch(() => {});
+      await defaultDaprContainer.stop();
+    }, 20000);
   });
 
   describe("binding", () => {
diff --git a/test/e2e/helpers/DaprGrpcAppContainer.ts b/test/e2e/helpers/DaprGrpcAppContainer.ts
index d02a0df6..631a4f8c 100644
--- a/test/e2e/helpers/DaprGrpcAppContainer.ts
+++ b/test/e2e/helpers/DaprGrpcAppContainer.ts
@@ -30,16 +30,8 @@ import {
   StoppedTestContainer,
   Wait,
 } from "testcontainers";
-import {
-  Component,
-  DaprPlacementContainer,
-  DaprSchedulerContainer,
-} from "@dapr/testcontainer-node";
-import {
-  DAPR_TEST_RUNTIME_IMAGE,
-  DAPR_TEST_PLACEMENT_IMAGE,
-  DAPR_TEST_SCHEDULER_IMAGE,
-} from "./containers";
+import { Component, DaprPlacementContainer, DaprSchedulerContainer } from "@dapr/testcontainer-node";
+import { DAPR_TEST_RUNTIME_IMAGE, DAPR_TEST_PLACEMENT_IMAGE, DAPR_TEST_SCHEDULER_IMAGE } from "./containers";
 
 const DAPRD_HTTP_PORT = 3500;
 const DAPRD_GRPC_PORT = 50001;
@@ -180,7 +172,12 @@ export class DaprGrpcAppContainer extends GenericContainer {
       cmds.push("--app-port", this.appPort.toString());
     }
     if (this.maxRequestSizeMb !== undefined) {
-      cmds.push("--dapr-http-max-request-size", this.maxRequestSizeMb.toString());
+      const size = `${this.maxRequestSizeMb}Mi`;
+
+      // Only override when explicitly requested
+      cmds.push("--max-body-size", size);
+    } else {
+      // DO NOTHING → let Dapr default (4MB) remain
     }
 
     this.withCommand(cmds);
diff --git a/test/e2e/http/server.test.ts b/test/e2e/http/server.test.ts
index 9094d223..a133648d 100644
--- a/test/e2e/http/server.test.ts
+++ b/test/e2e/http/server.test.ts
@@ -46,10 +46,7 @@ describe("http/server", () => {
 
   beforeAll(async () => {
     network = await new Network().start();
-    [redisContainer, mqttContainer] = await Promise.all([
-      startRedisContainer(network),
-      startMqttContainer(network),
-    ]);
+    [redisContainer, mqttContainer] = await Promise.all([startRedisContainer(network), startMqttContainer(network)]);
 
     // Allow the Dapr container to call back to the app server on the host.
     await TestContainers.exposeHostPorts(parseInt(serverPort));