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WSS
wss://stream.blockdb.io/v1/evm/
Messages
subscribe
type:object
unsubscribe
type:object
subscribe_response
type:object
unsubscribe_response
type:object
update
type:object

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Description

The Function Results stream delivers on-chain function call return values captured as blocks are finalized. Use this stream to monitor contract state or configuration values in real-time.

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Subscription Parameters

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chain_id
number
required
Target EVM network.
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contract_addresses
string[]
Filter by contract addresses (hex string, 20 bytes, no 0x prefix).
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signature_hashes
string[]
Filter by 4-byte function selectors (e.g., 0902f1ac).

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Message Fields

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contract_address
string
Contract queried.
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signature_hash
string
4-byte selector for the function invoked.
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result
string
Hex-encoded return payload.
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block_number
number
Snapshot block height when the value was observed.
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_tracing_id
string
Lineage identifier for cross-referencing.

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Subscription Example

# Use wscat to connect and subscribe
wscat -c wss://stream.blockdb.io/v1/evm/ \
  -H "Authorization: Bearer $BLOCKDB_API_KEY" \
  -x '{"action": "subscribe", "dataset_id": "0105", "chain_id": 1, "params": {"signature_hashes": ["0902f1ac"]}}'

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Response Example

{
  "chain_id": 1,
  "dataset_id": "0105",
  "is_reorg": false,
  "data": {
    "contract_address": "1234567890abcdef1234567890abcdef12345678",
    "signature_hash": "0902f1ac",
    "block_number": 18934560,
    "timestamp_utc": "2024-04-01T12:34:56Z",
    "call_data": "0902f1ac",
    "result": "0000000000000000000000000000000000000000000000000de0b6b3a7640000",
    "_tracing_id": "0105000000000000000000000000000000000001",
    "_created_at": "2025-11-11T18:42:15.123Z"
  }
}