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

# Application specific data

> There are times when attaching additional information to an order is useful. For example:

* An integration partner might want to track the volume they bring to the protocol
* A user might want to include a referral address in their order
* A user might want to specify additional order options, such as [CoW Hooks](/cow-protocol/reference/core/intents/hooks)

CoW Protocol facilitates the inclusion of this additional information to any order through a special data field known as [`appData`](/cow-protocol/reference/contracts/core/settlement#gpv2orderdata-struct). This field is a `bytes32` that points to an IPFS document that is a JSON file containing this information. Utilizing only on-chain data and IPFS, the content of this document can be retrieved and parsed.

## AppData Document

The AppData document is a JSON file that follows a specific JSON [schema](#schema). It is versioned and the version is specified in the document itself. Versioning follows [Semantic Versioning](https://semver.org/).

An example of an AppData document is:

```
{  "version": "1.6.0",  "appCode": "MyAwesomeUi",  "metadata": {    "referral": "0x1234567890123456789012345678901234567890"  }}
```

<Check>
  Avoid all the pain of creating and parsing `appData` by using either the:

  * [CoW Explorer appData utility](https://explorer.cow.fi/appdata?tab=encode); or
  * [app-data](https://github.com/cowprotocol/cow-sdk/blob/main/packages/app-data/README.md) SDK
</Check>

<Warning>
  If not using the CoW Explorer appData utility or the app-data SDK, make sure to follow the [appData schema](#schema) and upload your file to IPFS before placing orders using the resulting digest.
</Warning>

## Schema

The schema for the AppData document is defined in [JSON schema](https://json-schema.org/). The schema is available in the [app-data](https://github.com/cowprotocol/cow-sdk/blob/main/packages/app-data/README.md) SDK. The schema is shown below: