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WSS
Messages
subscribe
type:object
unsubscribe
type:object
subscribe_response
type:object
unsubscribe_response
type:object
update
type:object

​
Overview

  • Dataset ID: 0305 - Flash Loan Prints
  • Description: One row per borrowed token per on-chain flash loan event (V2-style flash swap, V3 Flash event, Balancer V2 Vault, etc.). pool_uid is NULL for vault-level events not tied to a single pool.
  • Sample: Hugging Face Sample

​
Subscription Parameters

​
chain_id
number
required
Target EVM network. See the Chain enumeration.
​
pool_uids
string[]
Optional filters: pool UIDs (32-byte hex, no 0x prefix).
​
flash_loan_source_addresses
string[]
Optional filters: emitter contracts (pool or vault), 20-byte hex without 0x.
​
token_addresses
string[]
Optional filters: borrowed token addresses (hex, no 0x).

​
Message Fields

​
pool_uid
string | null
Pool id when pool-scoped; null for vault-level events.
​
exchange_id
number | null
Exchange identifier when pool-scoped.
​
type_id
number | null
Pool type identifier when pool-scoped.
​
flash_loan_source
string
Address of the contract that emitted the event (hex).
​
token
string
Borrowed token address (hex).
​
amount_borrowed
string
Raw borrowed amount (decimal string).
​
amount_repaid
string
Raw repaid amount (decimal string).
​
fee_amount
string
Raw fee paid: amount_repaid − amount_borrowed (decimal string).
​
block_number
number
Event block.
​
block_time
string
Block time (ISO-8601).
​
tx_index
number
Transaction index.
​
log_index
number
Log index.
​
_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": "0305", "chain_id": 1, "params": {}}'

​
Response Example

{
  "chain_id": 1,
  "dataset_id": "0305",
  "is_reorg": false,
  "data": {
    "block_number": 19000050,
    "block_time": "2025-11-11T10:00:00Z",
    "tx_index": 12,
    "log_index": 3,
    "pool_uid": "88e6a0c2ddd26feeb64f039a2c41296fcb3f5640000000000000000000000000",
    "exchange_id": 1,
    "type_id": 201,
    "flash_loan_source": "88e6a0c2ddd26feeb64f039a2c41296fcb3f564",
    "token": "c02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "amount_borrowed": "1000000000000000000",
    "amount_repaid": "1003000000000000000",
    "fee_amount": "3000000000000000",
    "_tracing_id": "0305c0ffee000000000000000000000000000000000000000000000000000001",
    "_parent_tracing_ids": [
      "0103c0ffee000000000000000000000000000000000000000000000000000001"
    ],
    "_created_at": "2025-11-11T10:00:05Z",
    "_updated_at": "2025-11-11T10:00:05Z"
  }
}
Last modified on April 6, 2026