Step 3. Create a Variable
Create a variable to monitor transactions for specific wallets or addresses.
NoteEach call incurs a fixed CU charge, plus additional CUs for API operations. See the Compute Units Usage page for details.
As outlined in the Introduction page, event streaming supports two variable types:
address
, which will produceconfirmed_tx
andconfirmed_balance
.event_type
, which will produceblock
.
Both variables return an id
which is the unique identifier of the resource. We need this id
for two reasons:
- To reference the variables used in a rule.
- To add values to a variable.
In this step, we'll create a variable of type address
.
Request Payload
curl --location 'https://svc.blockdaemon.com/streaming/v2/variables' \
--header 'Content-Type: application/json' \
--header 'Accept: application/json' \
--data '
{
"description": "Polkadot mainnet addresses",
"name": "Polkadot mainnet addresses",
"type": "string"
}'
Response Payload
A successful response will return a "201 - Created" status with the variable details.
{
"created_at": "2024-03-06T14:44:40.940488Z",
"description": "Polkadot mainnet addresses",
"id": "3c1c1483-d8e0-4ecb-95a0-1e18a5d03244",
"name": "Polkadot mainnet addresses",
"type": "string",
"updated_at": "2024-03-06T14:44:40.940488Z"
}
Managing Variable
Update an existing variable using its ID. All fields in the request body will replace the existing values.
Example Payload
curl --request PUT \
--url https://svc.blockdaemon.com/streaming/v2/variables/{VARIABLE ID HERE} \
--header 'accept: application/json' \
--header 'authorization: Bearer YOUR_API_KEY' \
--header 'content-type: application/json' \
--data '
{
"name": "new name",
"description": "new description",
"type": "string | number | bool"
}
'
{
"id": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
"name": "new name",
"description": "new description",
"type": "string",
"created_at": "2025-08-05T14:26:13.150Z",
"updated_at": "2025-08-05T14:26:13.150Z"
}
Delete a variable by its ID. This action cannot be undone.
Example Payload
curl --request DELETE \
--url https://svc.blockdaemon.com/streaming/v2/variables/{VARIABLE ID HERE} \
--header 'accept: application/json' \
--header 'authorization: Bearer YOUR_API_KEY'
A 204 response status indicates the variable was successfully deleted.
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Updated 29 days ago