> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hologram.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Create a SIM webhook

> Use the Webhook tab to configure a webhook for your SIM to receive device messages and enable inbound messaging through the Hologram dashboard. Webhooks allow you to send authenticated messages to a SIM from external services using the Embedded API.

## How do I create a SIM webhook?

<Steps>
  <Step title="Find the SIM">
    First find the SIM's details page from the **SIMs** pages or using **global search**.
  </Step>

  <Step title="Open the Webhooks tab">
    Open the **Webhook** tab for the SIM, and in the **Configure inbound webhook** card, click the **Generate webhook** button.

    <Frame>
      <img src="https://mintcdn.com/hologram-b29df2a6/qhedpIaLSAn1x-cP/images/sims/sim-webhook-tab.webp?fit=max&auto=format&n=qhedpIaLSAn1x-cP&q=85&s=2383b6f3d21e302e57d90969110f23a9" alt="Generate a webhook card" width="2876" height="1300" data-path="images/sims/sim-webhook-tab.webp" />
    </Frame>
  </Step>

  <Step title="Configure the webhook">
    In the card that appears, enter the port number that will receive messages, and the protocol (TCP or UDP).
  </Step>
</Steps>

After your webhook is created, you can find the generated URL and port to use listed in the **Configure inbound webhook** card.

<img src="https://mintcdn.com/hologram-b29df2a6/qhedpIaLSAn1x-cP/images/sims/sim-webhook-card-generated.webp?fit=max&auto=format&n=qhedpIaLSAn1x-cP&q=85&s=184dee5e0142c22ae26f38c6dfcd0eb8" alt="Generated webhook card" width="2210" height="568" data-path="images/sims/sim-webhook-card-generated.webp" />

## Where do I find the SIM's webhook key?

Your Hologram webhook key is a device-specific identifier used to authenticate your SIM. This key is included in the JSON message body when sending messages to the webhook.

<Steps>
  <Step title="Open the Webhooks tab">
    From the SIM's details page, open the **Webhook** tab and click the **Show key** button in the **Webhook key** card.

    <Frame>
      <img src="https://mintcdn.com/hologram-b29df2a6/qhedpIaLSAn1x-cP/images/sims/sim-webhook-tab-key.webp?fit=max&auto=format&n=qhedpIaLSAn1x-cP&q=85&s=56344ba22ea48437c3741f5461bcbdbb" alt="Webhooks tab showing the Show key button in the Webhook key card" width="2876" height="1300" data-path="images/sims/sim-webhook-tab-key.webp" />
    </Frame>
  </Step>

  <Step title="View and manage the key">
    A modal will appear that displays your webhook key. You can copy the key or generate a new one. Webhook keys do not expire.

    <Frame>
      <img src="https://mintcdn.com/hologram-b29df2a6/qhedpIaLSAn1x-cP/images/sims/sim-webhook-key-modal.webp?fit=max&auto=format&n=qhedpIaLSAn1x-cP&q=85&s=4775800c2b0e4cedbefd88c3bcedff8b" alt="Modal displaying the webhook key with options to copy or generate a new key" width="1315" height="457" data-path="images/sims/sim-webhook-key-modal.webp" />
    </Frame>
  </Step>
</Steps>

## How do I send a message to a SIM's webhook?

After generating a webhook and getting your device's webhook key, use the following HTTP request to send a message to your SIM. The body is a JSON object with the following fields:

* `k` or `devicekey` — The device's webhook key
* `d` or `data` — The message data
* `t` or `tags` - The custom tag name

The custom tag name is optional and can be used to add custom tags (topics) to the event.

### HTTP Request

```http theme={null}
POST https://dashboard.hologram.io/api/1/devices/messages/YOUR_DEVICE_ID/UNIQUE_GENERATED_WEBHOOK_ID
```

### Request Body

```json theme={null}
{"k":"DEVICE_KEY","d":"Your message data goes here.","t":"YOUR_CUSTOM_TAG_NAME"}
```

## How to configure webhooks using the REST API

<Card title="REST API endpoints" href="/api/1/devices/deviceid/webhook/get">
  Configure device webhooks <code>GET/POST/PUT/DELETE /devices/{"{deviceId}"}/webhook</code>
</Card>

## Related actions

<Card title="Send messages to SIMs" href="/dashboard/sim-actions/send-messages-to-sims">
  Send TCP, UDP, or SMS messages to your devices
</Card>

<Card title="Troubleshooting webhooks" href="/guides/troubleshooting/troubleshooting-alerts-and-webhooks">
  Fix common webhook configuration issues
</Card>

<Info>
  **Limited access:** Only Owners, Admins, and Managers can see the **Webhook** tab and configure webhooks. Editors can see whether a SIM has a webhook on the **SIM details** tab.
</Info>


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