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 for supported values.
​
address
string
Filter notifications to a specific ERC-20 token address (hex string, 20 bytes, no 0x prefix).

​
Message Fields

​
contract_id
string
Unique contract incarnation ID (26 bytes hex).
​
contract_address
string
Token contract address (hex string, 20 bytes, no 0x prefix).
​
block_number
number
Block where the token was first recognized.
​
block_time
string
Block time (ISO-8601).
​
tx_index
number
Transaction index within the block.
​
name
string | null
Token name from name() (optional in EIP-20).
​
symbol
string | null
Token symbol from symbol() (optional in EIP-20).
​
decimals
number | null
Token decimals from decimals() (optional in EIP-20).
​
_tracing_id
string
Row-level lineage hash for correlation.
​
_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": "0201", "chain_id": 1, "params": {}}'

​
Response Example

{
  "chain_id": 1,
  "dataset_id": "0201",
  "is_reorg": false,
  "data": {
    "contract_id": "0000000000000000000000000000000000000000000000000000",
    "contract_address": "0000000000000000000000000000000000000001",
    "block_number": 567890,
    "block_time": "2018-07-07T12:34:56Z",
    "tx_index": 4,
    "name": "Token Name",
    "symbol": "TOKEN",
    "decimals": 18,
    "_tracing_id": "0201000000000000000000000000000000000001",
    "_parent_tracing_ids": [
      "0103000000000000000000000000000000000001",
      "0103000000000000000000000000000000000002"
    ],
    "_created_at": "2025-11-11T18:42:15.123Z",
    "_updated_at": "2025-11-11T18:42:15.123Z"
  }
}
Last modified on April 6, 2026