Skip to main content
WSS
Messages
subscribe
type:object
unsubscribe
type:object
subscribe_response
type:object
unsubscribe_response
type:object
update
type:object

​
Overview

​
Subscription Parameters

​
chain_id
number
required
Target EVM network. See the Chain enumeration.
​
contract_address
string
Optional filter: one collection contract (20-byte hex, no 0x prefix).

​
Message Fields

​
contract_id
string
Unique contract incarnation ID (26 bytes hex).
​
contract_address
string
Collection contract address (20-byte hex).
​
block_number
number
Block where the collection was first recognized.
​
block_time
string
Block time (ISO-8601).
​
tx_index
number
Transaction index within the block.
​
name
string | null
Collection name from name() (ERC721Metadata, optional).
​
symbol
string | null
Collection symbol from symbol() (ERC721Metadata, optional).
​
token_uri
string | null
Representative sample from the discovery probe.
​
supports_metadata
boolean | null
Whether the contract supports the ERC721Metadata extension; null when detection was via fallback.
​
supports_enumerable
boolean | null
Whether the contract supports the ERC721Enumerable extension; null when detection was via fallback.
​
_tracing_id
string
Lineage id (hex).
​
_parent_tracing_ids
string[]
Parent lineage ids (hex).
​
_created_at
string
Record creation time (ISO-8601).
​
_updated_at
string
Record last update time (ISO-8601).

​
Subscription Example

# Use wscat to connect and subscribe
wscat -c wss://api.blockdb.io/v1/evm/ \
  -H "Authorization: Bearer $BLOCKDB_API_KEY" \
  -x '{"action": "subscribe", "dataset_id": "0202", "chain_id": 1, "params": {}}'

​
Response Example

{
  "chain_id": 1,
  "dataset_id": "0202",
  "is_reorg": false,
  "data": {
    "contract_id": "0000000000000000000000000000000000000000000000000000",
    "contract_address": "bc4ca0eda7647a8ab7c2061c2e118a18a936f13d",
    "block_number": 12287507,
    "block_time": "2021-04-22T23:43:17Z",
    "tx_index": 114,
    "name": "BoredApeYachtClub",
    "symbol": "BAYC",
    "token_uri": "ipfs://QmeSjSinHpPnmXmspMjwiXyN6zS4E9zccariGR3jxcaWtq/",
    "supports_metadata": true,
    "supports_enumerable": true,
    "_tracing_id": "0202000000000000000000000000000000000001",
    "_parent_tracing_ids": [
      "0103000000000000000000000000000000000001"
    ],
    "_created_at": "2025-11-11T18:42:15.123Z",
    "_updated_at": "2025-11-11T18:42:15.123Z"
  }
}
Last modified on April 6, 2026