---
title: Instrumenting Node.js Serverless Applications Using the Datadog Forwarder
description: Datadog, the leading service for cloud-scale monitoring.
breadcrumbs: >-
  Docs > Serverless > Serverless Monitoring Guides > Instrumenting Node.js
  Serverless Applications Using the Datadog Forwarder
---

# Instrumenting Node.js Serverless Applications Using the Datadog Forwarder

## Overview{% #overview %}

{% alert level="danger" %}
If you are a new user of Datadog Serverless, follow the [instructions to instrument your Lambda functions using the Datadog Lambda Extension](https://docs.datadoghq.com/serverless/installation/nodejs) instead. If you have setup Datadog Serverless with the Datadog Forwarder before Lambda offered out-of-the-box functionality, use this guide to maintain your instance.
{% /alert %}

## Prerequisites{% #prerequisites %}

The [Datadog Forwarder Lambda function](https://docs.datadoghq.com/serverless/forwarder) is required to ingest AWS Lambda traces, enhanced metrics, custom metrics, and logs.

## Configuration{% #configuration %}

{% tab title="Datadog CLI" %}
The Datadog CLI modifies existing Lambda functions' configurations to enable instrumentation without requiring a new deployment. It is the quickest way to get started with Datadog's serverless monitoring.

You can also add the command to your CI/CD pipelines to enable instrumentation for all your serverless applications. Run the command *after* your normal serverless application deployment, so that changes made by the Datadog CLI command are not overridden.

### Install{% #install %}

Install the Datadog CLI with NPM or Yarn:

```sh
# NPM
npm install -g @datadog/datadog-ci @datadog/datadog-ci-plugin-lambda

# Yarn
yarn global add @datadog/datadog-ci @datadog/datadog-ci-plugin-lambda
```

### Instrument{% #instrument %}

To instrument the function, run the following command with your [AWS credentials](https://docs.aws.amazon.com/sdk-for-javascript/v2/developer-guide/setting-credentials-node.html).

```sh
datadog-ci lambda instrument -f <functionname> -f <another_functionname> -r <aws_region> -v <layer_version> --forwarder	<forwarder_arn>
```

To fill in the placeholders:

- Replace `<functionname>` and `<another_functionname>` with your Lambda function names.
- Replace `<aws_region>` with the AWS region name.
- Replace `<layer_version>` with the desired version of the Datadog Lambda Library. The latest version is `137`.
- Replace `<forwarder_arn>` with the Forwarder ARN (see the [Forwarder documentation](https://docs.datadoghq.com/serverless/forwarder/)).

For example:

```sh
datadog-ci lambda instrument -f my-function -f another-function -r us-east-1 -v 137 --forwarder "arn:aws:lambda:us-east-1:000000000000:function:datadog-forwarder"
```

If your Lambda function is configured to use code signing, you must add Datadog's Signing Profile ARN (`arn:aws:signer:us-east-1:464622532012:/signing-profiles/DatadogLambdaSigningProfile/9vMI9ZAGLc`) to your function's [Code Signing Configuration](https://docs.aws.amazon.com/lambda/latest/dg/configuration-codesigning.html#config-codesigning-config-update) before you can instrument it with the Datadog CLI.

More information and additional parameters can be found in the [CLI documentation](https://docs.datadoghq.com/serverless/serverless_integrations/cli).
{% /tab %}

{% tab title="Serverless Framework" %}
The [Datadog Serverless Plugin](https://docs.datadoghq.com/serverless/serverless_integrations/plugin) automatically adds the Datadog Lambda library to your functions using layers, and configures your functions to send metrics, traces, and logs to Datadog through the [Datadog Forwarder](https://docs.datadoghq.com/serverless/forwarder/).

If your Lambda function is configured to use code signing, you must add Datadog's Signing Profile ARN (`arn:aws:signer:us-east-1:464622532012:/signing-profiles/DatadogLambdaSigningProfile/9vMI9ZAGLc`) to your function's [Code Signing Configuration](https://docs.aws.amazon.com/lambda/latest/dg/configuration-codesigning.html#config-codesigning-config-update) before you install the Datadog Serverless Plugin.

To install and configure the Datadog Serverless Plugin, follow these steps:

1. Install the Datadog Serverless Plugin:
   ```
   yarn add --dev serverless-plugin-datadog
   ```
1. In your `serverless.yml`, add the following:
   ```
   plugins:
     - serverless-plugin-datadog
   ```
1. In your `serverless.yml`, also add the following section:
   ```
   custom:
     datadog:
       forwarderArn: # The Datadog Forwarder ARN goes here.
   ```
More information on the Datadog Forwarder ARN or installation can be found [here](https://docs.datadoghq.com/serverless/forwarder/). For additional settings, see the [plugin documentation](https://docs.datadoghq.com/serverless/serverless_integrations/plugin).

**Note**: You need to follow these [additional configuration steps](https://docs.datadoghq.com/serverless/guide/serverless_tracing_and_webpack/) if your Lambda function is simultaneously using Datadog's tracing libraries and [webpack](https://webpack.js.org/).
{% /tab %}

{% tab title="AWS SAM" %}
The [Datadog CloudFormation macro](https://docs.datadoghq.com/serverless/serverless_integrations/macro) automatically transforms your SAM application template to add the Datadog Lambda library to your functions using layers, and configure your functions to send metrics, traces, and logs to Datadog through the [Datadog Forwarder](https://docs.datadoghq.com/serverless/forwarder/).

### Install{% #install %}

Run the following command with your [AWS credentials](https://docs.aws.amazon.com/cli/latest/userguide/cli-chap-configure.html) to deploy a CloudFormation stack that installs the macro AWS resource. You only need to install the macro once for a given region in your account. Replace `create-stack` with `update-stack` to update the macro to the latest version.

```sh
aws cloudformation create-stack \
  --stack-name datadog-serverless-macro \
  --template-url https://datadog-cloudformation-template.s3.amazonaws.com/aws/serverless-macro/latest.yml \
  --capabilities CAPABILITY_AUTO_EXPAND CAPABILITY_IAM
```

The macro is now deployed and ready to use.

### Instrument{% #instrument %}

In your `template.yml`, add the following under the `Transform` section, **after** the `AWS::Serverless` transform for SAM.

```yaml
Transform:
  - AWS::Serverless-2016-10-31
  - Name: DatadogServerless
    Parameters:
      stackName: !Ref "AWS::StackName"
      nodeLayerVersion: "137"
      forwarderArn: "<FORWARDER_ARN>"
      service: "<SERVICE>" # Optional
      env: "<ENV>" # Optional
```

To fill in the placeholders:

- Replace `<FORWARDER_ARN>` with Forwarder ARN (see the [Forwarder documentation](https://docs.datadoghq.com/serverless/forwarder/)).
- Replace `<SERVICE>` and `<ENV>` with your service and environment values.

If your Lambda function is configured to use code signing, you must add Datadog's Signing Profile ARN (`arn:aws:signer:us-east-1:464622532012:/signing-profiles/DatadogLambdaSigningProfile/9vMI9ZAGLc`) to your function's [Code Signing Configuration](https://docs.aws.amazon.com/lambda/latest/dg/configuration-codesigning.html#config-codesigning-config-update) before you can use the macro.

More information and additional parameters can be found in the [macro documentation](https://docs.datadoghq.com/serverless/serverless_integrations/macro).
{% /tab %}

{% tab title="AWS CDK" %}
The [Datadog CDK Constructs](https://www.npmjs.com/package/datadog-cdk-constructs-v2) automatically configure ingestion of metrics, traces, and logs from your serverless applications by:

- Installing and configuring the Datadog Lambda library for your Python and Node.js Lambda functions.
- Enabling the collection of traces and custom metrics from your Lambda functions.
- Managing subscriptions from the Datadog Forwarder to your Lambda function log groups.

### Install{% #install %}

Run the following Yarn or NPM command in your CDK project to install the Datadog CDK Constructs library:

```sh
#Yarn
yarn add --dev datadog-cdk-constructs-v2

#NPM
npm install datadog-cdk-constructs-v2 --save-dev
```

### Instrument{% #instrument %}

To instrument the function, import the `datadog-cdk-construct` module in your AWS CDK app and add the following configurations (this example is TypeScript, but usage in other languages is similar):

```typescript
import * as cdk from "@aws-cdk/core";
import { DatadogLambda } from "datadog-cdk-constructs-v2";

class CdkStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);
    const datadogLambda = new DatadogLambda(this, "DatadogLambda", {
      nodeLayerVersion: 137,
      forwarderArn: "<FORWARDER_ARN>",
      service: "<SERVICE>",  // Optional
      env: "<ENV>",  // Optional
    });
    datadog.addLambdaFunctions([<LAMBDA_FUNCTIONS>])
  }
}
```

To fill in the placeholders:

- Replace `<FORWARDER_ARN>` with Forwarder ARN (see the [Forwarder documentation](https://docs.datadoghq.com/serverless/forwarder/)).
- Replace `<SERVICE>` and `<ENV>` with your service and environment values.

If your Lambda function is configured to use code signing, you must add Datadog's Signing Profile ARN (`arn:aws:signer:us-east-1:464622532012:/signing-profiles/DatadogLambdaSigningProfile/9vMI9ZAGLc`) to your function's [Code Signing Configuration](https://docs.aws.amazon.com/lambda/latest/dg/configuration-codesigning.html#config-codesigning-config-update) before you can use the macro.

More information and additional parameters can be found in the [Datadog CDK NPM page](https://www.npmjs.com/package/datadog-cdk-constructs-v2).
{% /tab %}

{% tab title="Container Image" %}
### Install{% #install %}

If you are deploying your Lambda function as a container image, you cannot use the Datadog Lambda Library as a layer. Instead, you must install the Datadog Lambda Library as a dependency of your function within the image. If you are using Datadog tracing, you must also install `dd-trace`.

**NPM**:

```sh
npm install --save datadog-lambda-js dd-trace
```

**Yarn**:

```sh
yarn add datadog-lambda-js dd-trace
```

**Note**: The minor version of the `datadog-lambda-js` package always matches the layer version. For example, `datadog-lambda-js v0.5.0` matches the content of layer version 5.

### Configure{% #configure %}

Follow these steps to configure the function:

1. Set your image's `CMD` value to `node_modules/datadog-lambda-js/dist/handler.handler`. You can set this in AWS or directly in your Dockerfile. **Note**: The value set in AWS overrides the value in the Dockerfile if you set both.
1. Set the following environment variables in AWS:

- Set `DD_LAMBDA_HANDLER` to your original handler, for example, `myfunc.handler`.
- Set `DD_TRACE_ENABLED` to `true`.
- Set `DD_FLUSH_TO_LOG` to `true`.
Optionally add `service` and `env` tags with appropriate values to your function.
### Subscribe{% #subscribe %}

Subscribe the Datadog Forwarder Lambda function to each of your functions' log groups in order to send metrics, traces, and logs to Datadog.

1. [Install the Datadog Forwarder if you haven't](https://docs.datadoghq.com/serverless/forwarder/).
1. [Subscribe the Datadog Forwarder to your function's log groups](https://docs.datadoghq.com/logs/guide/send-aws-services-logs-with-the-datadog-lambda-function/#collecting-logs-from-cloudwatch-log-group).

{% /tab %}

{% tab title="Custom" %}
### Install{% #install %}

The Datadog Lambda Library can be imported as a layer or JavaScript package.

The minor version of the `datadog-lambda-js` package always matches the layer version. For example, datadog-lambda-js v0.5.0 matches the content of layer version 5.

#### Using the layer{% #using-the-layer %}

[Configure the layers](https://docs.aws.amazon.com/lambda/latest/dg/configuration-layers.html) for your Lambda function using the ARN in the following format.

```
# For us,us3,us5,eu, ap1, and ap2 regions
arn:aws:lambda:<AWS_REGION>:464622532012:layer:Datadog-<RUNTIME>:<VERSION>

# For us-gov regions
arn:aws-us-gov:lambda:<AWS_REGION>:002406178527:layer:Datadog-<RUNTIME>:<VERSION>
```

The available `RUNTIME` options are: `Node18-x`, `Node20-x`, `Node22-x`, `Node24-x`. The latest `VERSION` is `137`. For example:

```
arn:aws:lambda:us-east-1:464622532012:layer:Datadog-Node24-x:137
```

If your Lambda function is configured to use code signing, you must add Datadog's Signing Profile ARN (`arn:aws:signer:us-east-1:464622532012:/signing-profiles/DatadogLambdaSigningProfile/9vMI9ZAGLc`) to your function's [Code Signing Configuration](https://docs.aws.amazon.com/lambda/latest/dg/configuration-codesigning.html#config-codesigning-config-update) before you can add the Datadog Lambda library as a layer.

#### Using the package{% #using-the-package %}

**NPM**:

```
npm install --save datadog-lambda-js
```

**Yarn**:

```
yarn add datadog-lambda-js
```

See the [latest release](https://www.npmjs.com/package/datadog-lambda-js).

### Configure{% #configure %}

Follow these steps to configure the function:

1. Set your function's handler to `/opt/nodejs/node_modules/datadog-lambda-js/handler.handler` if using the layer, or `node_modules/datadog-lambda-js/dist/handler.handler` if using the package.
1. Set the environment variable `DD_LAMBDA_HANDLER` to your original handler, for example, `myfunc.handler`.
1. Set the environment variable `DD_TRACE_ENABLED` to `true`.
1. Set the environment variable `DD_FLUSH_TO_LOG` to `true`.
1. Optionally add a `service` and `env` tag with appropriate values to your function.

**Note**: You need to follow these [additional configuration steps](https://docs.datadoghq.com/serverless/guide/serverless_tracing_and_webpack/) if your Lambda function is simultaneously using Datadog's tracing libraries and [webpack](https://webpack.js.org/).

### Subscribe{% #subscribe %}

Subscribe the Datadog Forwarder Lambda function to each of your function's log groups, in order to send metrics, traces, and logs to Datadog.

1. [Install the Datadog Forwarder if you haven't](https://docs.datadoghq.com/serverless/forwarder/).
1. [Subscribe the Datadog Forwarder to your function's log groups](https://docs.datadoghq.com/logs/guide/send-aws-services-logs-with-the-datadog-lambda-function/#collecting-logs-from-cloudwatch-log-group).

{% /tab %}

### Tag{% #tag %}

Although it's optional, Datadog recommends tagging you serverless applications with the `env`, `service`, and `version` tags following the [unified service tagging documentation](https://docs.datadoghq.com/getting_started/tagging/unified_service_tagging/#aws-lambda-functions).

## Explore{% #explore %}

After configuring your function following the steps above, view your metrics, logs, and traces on the [Serverless homepage](https://app.datadoghq.com/functions).

## Monitor custom business logic{% #monitor-custom-business-logic %}

If you would like to submit a custom metric or span, see the sample code below:

```javascript
const { sendDistributionMetric, sendDistributionMetricWithDate } = require("datadog-lambda-js");
const tracer = require("dd-trace");

// submit a custom span named "sleep"
const sleep = tracer.wrap("sleep", (ms) => {
  return new Promise((resolve) => setTimeout(resolve, ms));
});

exports.handler = async (event) => {
  // add custom tags to the lambda function span,
  // does NOT work when X-Ray tracing is enabled
  const span = tracer.scope().active();
  span.setTag('customer_id', '123456');

  await sleep(100);

  // submit a custom span
  const sandwich = tracer.trace('hello.world', () => {
    console.log('Hello, World!');
  });

  // submit a custom metric
  sendDistributionMetric(
    "coffee_house.order_value", // metric name
    12.45, // metric value
    "product:latte", // tag
    "order:online", // another tag
  );

  // submit a custom metric with timestamp
  sendDistributionMetricWithDate(
    "coffee_house.order_value", // metric name
    12.45, // metric value
    new Date(Date.now()), // date, must be within last 20 mins
    "product:latte", // tag
    "order:online", // another tag
  );

  const response = {
    statusCode: 200,
    body: JSON.stringify("Hello from serverless!"),
  };
  return response;
};
```

For more information on custom metric submission, see [Serverless Custom Metrics](https://docs.datadoghq.com/serverless/custom_metrics?tab=nodejs). For additional details on custom instrumentation, see the Datadog APM documentation for [custom instrumentation](https://docs.datadoghq.com/tracing/custom_instrumentation/nodejs/).

## Further Reading{% #further-reading %}