> For the complete documentation index, see [llms.txt](https://developer.barchart.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.barchart.com/getting-started/requesting-exchanges.md).

# Requesting Exchanges

Request the exchanges available to your username and configuration before subscribing. Openfeed Streaming sends an `ExchangeRequest` and returns an `ExchangeResponse`.

Use the returned exchange codes when creating exchange subscriptions. See [Subscribing to Market Data](/getting-started/subscribing-to-market-data.md) for subscription guidance.

### SDK examples

Use the SDK that matches your application:

* [Python SDK](/repos-sdks/python-sdk.md)
* [Java SDK](/repos-sdks/java-sdk.md)
* [.NET SDK](/repos-sdks/.net-sdk.md)

#### Python

```python
# Handle the exchange response.
def on_message(msg):
    print("Exchange Response:", msg)

# Request all available exchanges and their codes.
of_client.request_available_exchanges(callback=on_message)
```

#### Java

```java
@Override
public void onExchangeResponse(ExchangeResponse exchangeResponse) {
    System.out.println("Exchange Response: " + exchangeResponse);
}

client.exchangeRequest();
```

#### .NET

```csharp
var exchangeList = await client.GetExchangesAsync(CancellationToken.None);

Console.WriteLine("Exchanges Response: " + exchangeList);
```

### Protocol reference

See [api.proto](/architecture/openfeed-api-proto.md) for the `ExchangeRequest` and `ExchangeResponse` message definitions.


---

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