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

# Realtime

> Learn how to build a realtime dashboard with the Codex API subscriptions

In this guide we'll build a nodejs application that listens for price changes on a token in realtime. We'll show
how to do it two ways, one with webhooks and another with subscriptions.

## Webhooks

Install the Codex SDK

```
npm install @codex-data/sdk
```

Create a new file called `index.js` and add the following code:

```js theme={null}
const { Codex } = require('@codex-data/sdk');

const client = new Codex(process.env.CODEX_API_KEY);
```

Now we have to add the token address and network id to code so we can start listening for price changes.

```js theme={null}
const watchTokenAddress = '0xbb4cdb9cbd36b01bd1cbaebf2de08d9173bc095c';
const networkId = 56;
```

Next, we'll need be able to receive webhook deliveries  on our local computer. Let's use loophole to do this.

[https://loophole.cloud/download](https://loophole.cloud/download)

After getting that setup and seeing your loophole url, copy it and save it for later.

Now lets make the request to make a webook subscription, replacing the value for the  host

```js theme={null}
const hook = await client.mutation(`
  mutation CreateWebhooks {
    createWebhooks(
      input: {priceWebhooksInput: {webhooks: [{alertRecurrence: INDEFINITE, callbackUrl: "<my loophole url>", name: "uniswap", securityToken: "dasdsfds", groupId: "test-group", conditions: {tokenAddress: {eq: "0x5a98fcbea516cf06857215779fd812ca3bef1b32"}, networkId: {eq: 1}, priceUsd: {gt: "0"}}}]}}
    ) {
      priceWebhooks {
        alertRecurrence
        callbackUrl
        created
        id
        name
        webhookType
        groupId
        status
        conditions {
          ... on PriceEventWebhookCondition {
            __typename
            networkId {
              eq
            }
            priceUsd {
              eq
              gt
              gte
              lt
              lte
            }
            tokenAddress {
              eq
            }
          }
        }
      }
    }
  }
`)
```

## Subscriptions