### Important Note

Each call incurs a fixed CU charge, plus additional CUs for API operations. See the [Compute Units Usage](https://docs.blockdaemon.com/reference/compute-units-usage-events) page for details.

First, we need to get a list of supported protocols and networks that we'll be using to send and receive events. This can be done by using the **Overview** endpoint as shown below.

### Request Payload

```curl
curl --request GET \
     --url https://svc.blockdaemon.com/streaming/v2/ \
     --header 'X-API-Key: YOUR_API_KEY' \
     --header 'accept: application/json'
```

### Response Payload

The response is a JSON array containing objects that display a protocol overview.

200 - OK

```json
[
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_balance",
                    "confirmed_tx"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "bitcoin"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx",
                    "confirmed_balance"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "testnet",
        "protocol": "bitcoin"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx",
                    "confirmed_balance"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "reorg",
                    "block"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "testnet4",
        "protocol": "bitcoin"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_balance",
                    "confirmed_tx"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "bitcoincash"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx",
                    "confirmed_balance"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "dogecoin"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "staking_status",
                    "staking_reward",
                    "confirmed_tx_trace",
                    "confirmed_tx",
                    "confirmed_balance",
                    "confirmed_tx_log"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "reorg",
                    "block"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "ethereum"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx",
                    "confirmed_balance",
                    "confirmed_tx_log",
                    "confirmed_tx_trace"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "sepolia",
        "protocol": "ethereum"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "staking_status",
                    "staking_reward",
                    "confirmed_tx_trace",
                    "confirmed_tx",
                    "confirmed_balance",
                    "confirmed_tx_log"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "hoodi",
        "protocol": "ethereum"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx",
                    "confirmed_balance"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "litecoin"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_balance",
                    "confirmed_tx"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "polkadot"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx",
                    "confirmed_balance"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "westend",
        "protocol": "polkadot"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx_trace",
                    "confirmed_tx",
                    "confirmed_balance",
                    "confirmed_tx_log"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "optimism"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_balance",
                    "confirmed_tx_log",
                    "confirmed_tx"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "block",
                    "reorg"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "mainnet",
        "protocol": "polygon"
    },
    {
        "match_variable_supported": true,
        "match_variable_types": [
            {
                "data_source": [
                    "confirmed_tx",
                    "confirmed_balance",
                    "confirmed_tx_log"
                ],
                "variable_type": "address"
            },
            {
                "data_source": [
                    "reorg",
                    "block"
                ],
                "variable_type": "event_type"
            }
        ],
        "network": "amoy",
        "protocol": "polygon"
    }
]
```

Each object represents a protocol overview with the following fields:

| Fields | Details |
| --- | --- |
| `match_variable_types` | An array of supported match variable types for the protocol. |
| `source` | The data that will be received for each `variable_type`.<br>For example:<br>- `event_type` will produce `block` event.<br>- `address` will produce `confirmed_tx` and `confirmed_balance` events. |
| `variable_type` | The supported variable types.<br>In this case, we have options such as `address` and `event_type`. This implies that we can [create variables](https://docs.blockdaemon.com/docs/step-3-create-a-variable) later on and use them to match against `address` or `event_type`. |
| `network` | Associated network (e.g., mainnet). |
| `protocol` | Protocol name (e.g., polkadot, dogecoin, ethereum). |