> For the complete documentation index, see [llms.txt](https://docs.entangle.fi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.entangle.fi/universal-data-feeds/developer-guides/custom-data-feeds.md).

# Custom Data Feeds

{% hint style="info" %}
If you're looking for a data type that isn't currently supported but would like it to be, feel free to [contact us](https://entangle.zendesk.com/hc/en-us/requests/new), and we can discuss implementing it.
{% endhint %}

Custom data in data feeds refers to user-defined information that is integrated into a data feed to meet the specific needs of a dApp or smart contract. This enables developers to pull tailored data from both on-chain and off-chain sources, facilitating more accurate and relevant decision-making and operations. With UDF, users can easily expand the data available to their applications by incorporating new data types into the Entangle UDF infrastructure.

***

## When Is Custom Data Needed?

* **Integrating New Crypto Assets:** Add new cryptocurrency price feeds to ensure decentralized exchanges, lending platforms, or wallets always have the latest market prices.
* **Real-World Asset (RWA) Integration:** Introduce real-world assets like commodities, real estate, or physical goods into the decentralized ecosystem, enabling their tokenization and trading.
* **Proof of Reserves Integration:** Add external data feeds to verify asset reserves, providing transparency and confidence in the backing of digital assets or financial platforms.

***

## Requesting New Data Types

To integrate new data into UDF, [contact us](https://entangle.zendesk.com/hc/en-us/requests/new) and provide the following information:

* **Initial Data with Examples**: Share real sample data that will be processed during the integration.
* **Data Processing Requirements**: Outline any necessary transformations or formatting for the data to be delivered on-chain.
* **Update Frequency Suggestions**: Recommend the desired update frequency to tailor the integration to the protocol’s needs.

***

## Integration Process

This section outlines the process of integrating a new data feed into UDF. The default integration flow ensures smooth onboarding of new data sources and utilizes UDF’s capabilities for fetching, parsing, and distributing data on-chain.

{% stepper %}
{% step %}

### **Define REST URL Template**

The Rest URL template defines how data is fetched from external sources. You will need to create a URL template that points to the endpoint of the data provider. The template uses Go text syntax, with placeholders such as `DataKey` and `SourceID`. Example for Binance API:

```
https://api.binance.com/api/v3/avgPrice?symbol={{.DataKey}}
```

This URL template is inserted into the configuration file, allowing Entangle's backend to fetch the necessary data.
{% endstep %}

{% step %}

### **Set Up Parsing Pipelines**

In the configuration file, set up pipelines to parse data from the response JSON. Below is an example JSON response structure:

```json
{
  "asset": {
    "price": 1000000000000000000,
    "timestamp": 1721636387,
    "volume": 10000000000
  }
}
```

* **Pipeline for Price**: `asset.price`
* **Pipeline for Timestamp**: `asset.timestamp`
* **Pipeline for Volume**: `asset.volume`

These pipelines should be defined using GJSON syntax to extract the required fields.
{% endstep %}

{% step %}

### **Configure the System**

The next step is to implement both the URL template and parsing pipelines in the YAML configuration file. This connects the data feed with Entangle UDF.

Example configuration snippet:

```yaml
urlTemplate: "https://api.binance.com/api/v3/avgPrice?symbol={{.DataKey}}"
pipelines:
  - value: "asset.price"
  - timestamp: "asset.timestamp"
  - volume: "asset.volume"
```

{% endstep %}

{% step %}

### **Fetch Data**

To retrieve data updates, use the Finalized Data API. For example, to fetch the BTC/USD price feed, execute the following curl command:

```sh
curl https://udfsnap.ent-dx.com/last_votes?feedKeys=BTC/USD
```

Below is a sample response containing publisher votes along with their signatures, and data encoded as bytes in the `update_call_data` property which is ready to be used on-chain.

```json
{
  "update_call_data": "0x..",
  "feeds": [
    {
      "feed_key": "BTC/USD",
      "votes": [
        {
          "Value": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAS4fbe+zAAA=",
          "Timestamp": 1737093395,
          "Signature": {
            "R": "0xfb2e89fb52f1d832d5437f4b773c0f67749b914b25c592af9cbc8ffe58e9e928",
            "S": "0x3c7e717a67b8a0c072f0271f35f3994c865c12b930f20b57149b623cade43d43",
            "V": 27
          }
        },
        {
          "Value": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAS4fbe+zAAA=",
          "Timestamp": 1737093402,
          "Signature": {
            "R": "0xe6a1448feac17a219c63a426f978cd395f8be55a74ebc717a88385033c7c5432",
            "S": "0x1a16ba5138e5293b03c093097c8564c55a0f054537a6c665d3b4bc9cf716d46f",
            "V": 28
          }
        },
        {
          "Value": "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAS4fbe+zAAA=",
          "Timestamp": 1737093400,
          "Signature": {
            "R": "0x8308dc0d3b5a32a12374fbc8a2852cb14af4e31cc015b4d463e4cfb41d5aa469",
            "S": "0x12d5746c9499e7dc5edbbc436f696478ab4ad5a96247fb357d3d0c418769778d",
            "V": 28
          }
        }
      ]
    }
  ]
}
```

{% endstep %}

{% step %}

### **Finishing**

{% hint style="info" %}
**Monitor and Update**

Ongoing monitoring ensures that the integration functions correctly. Periodically review the configuration and update it as needed to accommodate changes in the data provider's API or Entangle’s system.
{% endhint %}

Once you have fetched the data, use the `PushMarketplace`or `PullMarketplace` smart contract to verify the updates on-chain.
{% endstep %}
{% endstepper %}