diff --git a/handler/handler.go b/handler/handler.go
index 7456326..62bf0b5 100644
--- a/handler/handler.go
+++ b/handler/handler.go
@@ -29,9 +29,45 @@ const (
 	maxStr   = "_max"
 )
 
-// Lambda response
-type response struct {
-	message string `json:"message"`
+type firehoseResponse struct {
+	RequestId    string `json:"requestId"`
+	Timestamp    int64  `json:"timestamp"`
+	ErrorMessage string `json:"errorMessage"`
+}
+
+func generateValidFirehoseResponse(statusCode int, requestId string, errorMessage string, err error) events.APIGatewayProxyResponse {
+	if errorMessage != "" {
+		data := firehoseResponse{
+			RequestId:    requestId,
+			Timestamp:    time.Now().Unix(),
+			ErrorMessage: fmt.Sprintf("%s %s", errorMessage, err),
+		}
+		jsonData, _ := json.Marshal(data)
+		return events.APIGatewayProxyResponse{
+			Body:       string(jsonData),
+			StatusCode: statusCode,
+			Headers: map[string]string{
+				"content-type": "application/json",
+			},
+			IsBase64Encoded:   false,
+			MultiValueHeaders: map[string][]string{},
+		}
+	} else {
+		data := firehoseResponse{
+			RequestId: requestId,
+			Timestamp: time.Now().Unix(),
+		}
+		jsonData, _ := json.Marshal(data)
+		return events.APIGatewayProxyResponse{
+			Body:       string(jsonData),
+			StatusCode: statusCode,
+			Headers: map[string]string{
+				"content-type": "application/json",
+			},
+			IsBase64Encoded:   false,
+			MultiValueHeaders: map[string][]string{},
+		}
+	}
 }
 
 // Takes a base64 encoded string and returns decoded string
@@ -157,7 +193,9 @@ func HandleRequest(ctx context.Context, request events.APIGatewayProxyRequest) (
 	}
 	if ca != nil {
 		parameterMap := ca["commonAttributes"].(map[string]interface{})
-		ListenerUrl = parameterMap["CUSTOM_LISTENER"].(string)
+		if parameterMap != nil {
+			ListenerUrl = parameterMap["CUSTOM_LISTENER"].(string)
+		}
 	}
 	if ListenerUrl == "" {
 		ListenerUrl = getListenerUrl()
@@ -168,6 +206,16 @@ func HandleRequest(ctx context.Context, request events.APIGatewayProxyRequest) (
 	if LogzioToken == "" {
 		LogzioToken = request.Headers["x-amz-firehose-access-key"]
 	}
+	// get requestId to match firehose response requirements
+	requestId := request.Headers["X-Amz-Firehose-Request-Id"]
+	if requestId == "" {
+		requestId = request.Headers["x-amz-firehose-request-id"]
+	}
+
+	if LogzioToken == "" {
+		log.Printf("Cant find access key in 'X-Amz-Firehose-Access-Key' or 'x-amz-firehose-access-key' headers")
+		return generateValidFirehoseResponse(400, requestId, "Cant find access key in 'X-Amz-Firehose-Access-Key' or 'x-amz-firehose-access-key' headers", nil), nil
+	}
 
 	// Initializing prometheus remote write exporter
 	cfg := &prometheusremotewriteexporter.Config{
@@ -193,19 +241,19 @@ func HandleRequest(ctx context.Context, request events.APIGatewayProxyRequest) (
 	metricsExporter, err := prometheusremotewriteexporter.NewPRWExporter(cfg, buildInfo)
 	if err != nil {
 		log.Printf("Error while creating metrics exporter: %s", err)
-		return events.APIGatewayProxyResponse{}, err
+		return generateValidFirehoseResponse(500, requestId, "Error while creating metrics exporter:", err), err
 	}
 	err = metricsExporter.Start(ctx, componenttest.NewNopHost())
 	if err != nil {
 		log.Printf("Error while starting metrics exporter: %s", err)
-		return events.APIGatewayProxyResponse{}, err
+		return generateValidFirehoseResponse(500, requestId, "Error while starting metrics exporter:", err), err
 	}
 	log.Println("Starting to parse request body")
 	var body map[string]interface{}
 	err = json.Unmarshal([]byte(request.Body), &body)
 	if err != nil {
 		log.Printf("Error while unmarshalling request body: %s", err)
-		return events.APIGatewayProxyResponse{}, err
+		return generateValidFirehoseResponse(500, requestId, "Error while unmarshalling request body:", err), err
 	}
 	/*
 		api request body example structure:
@@ -233,13 +281,13 @@ func HandleRequest(ctx context.Context, request events.APIGatewayProxyRequest) (
 		err = protoBuffer.DecodeMessage(ExportMetricsServiceRequest)
 		if err != nil {
 			log.Printf("Error decoding data: %s", err)
-			return events.APIGatewayProxyResponse{}, err
+			return generateValidFirehoseResponse(500, requestId, "Error decoding data:", err), err
 		}
 		// Converting otlp proto message to proto bytes
 		protoBytes, err := proto.Marshal(ExportMetricsServiceRequest)
 		if err != nil {
 			log.Printf("Error while converting otlp proto message to proto bytes: %s", err)
-			return events.APIGatewayProxyResponse{}, err
+			return generateValidFirehoseResponse(500, requestId, "Error while converting otlp proto message to proto bytes:", err), err
 		}
 		// Converting otlp proto bytes to pdata.metrics
 		metrics, err := pdata.MetricsFromOtlpProtoBytes(protoBytes)
@@ -273,11 +321,8 @@ func HandleRequest(ctx context.Context, request events.APIGatewayProxyRequest) (
 	err = metricsExporter.Shutdown(ctx)
 	if err != nil {
 		log.Printf("Error while shutting down exporter: %s", err)
-		return events.APIGatewayProxyResponse{}, err
-	}
-	resp := &response{
-		message: "Done",
+		return generateValidFirehoseResponse(500, requestId, "Error while shutting down exporter:", err), err
 	}
-	resBody, err := json.Marshal(resp)
-	return events.APIGatewayProxyResponse{Body: string(resBody), StatusCode: 200}, nil
+
+	return generateValidFirehoseResponse(200, requestId, "", nil), nil
 }