# Publish Data to AWS IoT using Flux

Publish Flux events to AWS IoT Core with a signed webhook action.

This guide explains how to use the [AWS Signature Version 4](https://docs.aws.amazon.com/general/latest/gr/signature-version-4.html) authentication to publish data to AWS IoT from Soracom Flux [Webhook Actions](https://docs.soracom.io/en/services/flux/webhook). By leveraging Signature V4 authentication, you can interact with AWS services without embedding credentials or Signature V4 generation logic on your devices.

## Step 1: Create an AWS IAM Policy and IAM Role

To allow the Soracom Flux Webhook Action to publish data to AWS IoT in your AWS account, set up the following IAM policy and role in your AWS account. You can perform your IAM setup using the AWS [IAM Console](https://console.aws.amazon.com/iam/).

- **IAM Policy**: Grant permissions to publish data to AWS IoT.

  - Service: IoT
  - Actions: Publish
  - Resource: Specify any region and topic.

  ![IAM Policy](https://docs.soracom.io/_astro/create-iam-role01.wf0v8BF__1ymeIv.webp)

- **IAM Role**:

  - Trust Entity: Specify Soracom's AWS account as a trusted entity.

    - Enter one of the following in the `Account ID` field according to the Soracom coverage type.

      - Global Coverage: `950858143650`
      - Japan Coverage: `762707677580`

  - External ID: Strengthen security by requiring an external ID.

  - Attach the IAM policy created above.

  ![IAM Role](https://docs.soracom.io/_astro/create-iam-role02.oA5-Eljk_1sFdn1.webp)

  The External ID and IAM role ARN will be used in [Step 3](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-3-register-aws-iam-role-credentials-in-the-soracom-user-console).

## Step 2: Confirm Device Data Endpoint for AWS IoT

1. Open the [AWS IoT Console](https://ap-northeast-1.console.aws.amazon.com/iot/home?region=ap-northeast-1#/home).

2. Select the AWS Region you intend to use in the console.

3. Navigate to **Domain configurations** and copy the domain name labeled `iot:Data-ATS` to your clipboard.

   ![Device Data Endpoint](https://docs.soracom.io/_astro/aws-iot-domain01.DWXC4GFW_25QqlW.webp)

   This domain name will be used in [Step 4](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-4-configure-a-flux-application).

## Step 3: Register AWS IAM Role Credentials in the Soracom User Console

Register the IAM role credentials in the [credential set](https://docs.soracom.io/en/services/authentication/credential-sets#creating-a-credential-set) menu in the Soracom User Console.

| Field | Value |
| - | - |
| Credential set ID | Any descriptive name, e.g., `AWS-IAM-role-credentials-flux-webhook` |
| Type | AWS IAM Role credentials |
| Role ARN | The ARN of your IAM role you created in [Step 1](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-1-create-an-aws-iam-policy-and-iam-role) |
| External ID | The external ID you entered in [Step 1](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-1-create-an-aws-iam-policy-and-iam-role) |

![AWS IAM Role Credentials](https://docs.soracom.io/_astro/credentials01.CgemvUdt_1B9AuH.webp)

## Step 4: Configure a Flux Application

Set up a Flux application to execute webhook actions. For this guide you use [API/Manual Execution Event Source](https://docs.soracom.io/en/services/flux/api) to manually send data.

1. Sign in to the **[User Console](https://console.soracom.io/?coverage_type=g)**. From the **☰ Menu**, expand **Soracom Flux** and select **Flux Apps**.

   ![Flux app01](https://docs.soracom.io/_astro/flux-config01.7Y2Fmy2r_alx0L.webp)

2. Click **+ Create a new Flux app**.

3. Enter the app **Name** and **Description**, then click **Create**.

   The Flux application will be created, and the **Studio** tab in **Soracom Flux Studio** will be displayed.

## Step 5: Add Event Source and Webhook Action to Flux App

1. Open the **Studio** tab in Soracom Flux Studio.

2. Click **+ Create a channel** and select event source of type **API/Manual Execution**, then click **Next**.

3. Enter the **Name** of the channel and optionally add a **Description**, then click **Create a new channel**.

   A channel connected to the event source will be created and a screen displaying the channel details will appear.

4. Click **Actions** > **+ Add Action**.

   The **Create a new action** dialog will appear.

5. Select **Webhook** and click **OK**.

   The **Create a new action: Webhook** dialog will appear.

6. Configure the following fields:

   | Field | Description |
   | - | - |
   | **Name** | Enter a name for the **Webhook** action. |
   | **Description** | Provide a brief summary of the Webhook action. |
   | **Enabled** | Set this option to **Enabled** to activate the action. |
   | **Action Condition** | Leave this blank to execute the action for all conditions. |

   ![Webhook Action Settings](https://docs.soracom.io/_astro/flux-config03.D4w1RR2L_Zq2abI.webp)

7. Continue with the following settings:

   | Field | Description |
   | - | - |
   | **HTTP Method** | Select the HTTP method for the Webhook. Choose **POST** here. |
   | **URL** | Enter the Webhook HTTP URL. Use the AWS IoT endpoint obtained in [Step 2](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-2-confirm-device-data-endpoint-for-aws-iot). Example: `https://<random-string>-ats.iot.ap-northeast-1.amazonaws.com/topics/<TopicName>/`. For this guide, use `test-topic` for the topic name. |
   | **Auth Type** | Select **AWS Signature V4**. |
   | **Service** | Enter the AWS IoT ServiceCode: `iotdata`. |
   | **Region** | Select the AWS IoT region used in [Step 2](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-2-confirm-device-data-endpoint-for-aws-iot). |
   | **Credentials** | Select the credentials registered in [Step 3](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-3-register-aws-iam-role-credentials-in-the-soracom-user-console). |

   ![Webhook Action Settings](https://docs.soracom.io/_astro/flux-config04.BeLFgaap_Z17yt21.webp)

8. Configure additional fields:

   | Field | Description |
   | - | - |
   | **HTTP Header** | Set the HTTP headers for the Webhook request. Selecting `application/json` for the HTTP body will auto-fill this. |
   | **HTTP Body** | Set the HTTP body for the Webhook request. Use `${payload}` to send the input data from the event source directly. |
   | **Output** | Configure whether the Webhook action's response should be sent to another channel. Set this to **Disabled**. |

   ![Webhook Action Settings](https://docs.soracom.io/_astro/flux-config05.BxFQXPKz_Z1LOMkp.webp)

9. Click **Create**.

   The Webhook action will be created and displayed under the **Actions** tab of the channel's details screen.

## Testing the Configuration

### Prepare the AWS IoT MQTT Test Client

1. Access the [AWS IoT Console](https://console.aws.amazon.com/iot/home).

2. From the left pane, click **MQTT test client**.

3. Click the **Subscribe to a topic** tab and enter the topic name you set in [Step 5](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-5-add-event-source-and-webhook-action-to-flux-app), e.g., `test-topic/#`.

   ![AWS MQTT Test Client](https://docs.soracom.io/_astro/aws-mqtt-test-client01.koXHuxV4_Z1gAG4.webp)

4. Click **Subscribe**.

---

### Send a Message Using API/Manual Execution

1. Sign in to the [User Console](https://console.soracom.io/?coverage_type=g) and navigate to the **Flux Apps** screen as shown in [Step 4](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-4-configure-a-flux-application).

2. Click the Flux Application you created in [Step 4](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-4-configure-a-flux-application).

3. Select the API/Manual Execution event source created in [Step 5](https://docs.soracom.io/en/services/flux/aws-iot-core/#step-5-add-event-source-and-webhook-action-to-flux-app).

   ![Select Event Source](https://docs.soracom.io/_astro/send-message01.BiDheEJY_Z25Cb2r.webp)

4. Click **Test** tab, then enter a message in the **Body** field to send to the channel. For example: `{"message":"Hello from Flux!"}`.

   ![Test Execution](https://docs.soracom.io/_astro/send-message02.Csr94vSn_qAClB.webp)

5. Click **Execute**.

6. Verify the message appears in the [AWS IoT MQTT Test Client](https://docs.soracom.io/en/services/flux/aws-iot-core/#prepare-the-aws-iot-mqtt-test-client).

   ![Verify Message](https://docs.soracom.io/_astro/send-message03.7BNOkGzg_Z1KFBPC.webp)

---

### View Flux App Execution History

You can also check execution history in the **History** tab of **Soracom Flux Studio**.

1. Sign in to the **[User Console](https://console.soracom.io/?coverage_type=g)**. From the **☰ Menu**, expand **Soracom Flux** and select **Flux Apps**.

2. Select the **Flux** app you created.

3. Click the **History** tab.

   You will see logs for each channel, including **Message**, **Context**, and the **Input** and **Output** of actions executed from that channel. For more details, see [View Logs](https://docs.soracom.io/en/services/flux/logs).