Event shapes

What data.event holds, per trigger. Three shapes: event-level, tx-level, and sBTC.

Event-level triggers

For stx_*, ft_*, nft_*, and print_event, data.event is { tx_id, type, event_index, data }:

Trigger	`event.type`	`event.data` fields
`stx_transfer`	`stx_transfer_event`	`sender?, recipient?, amount, memo`
`stx_mint`	`stx_mint_event`	`recipient?, amount`
`stx_burn`	`stx_burn_event`	`sender?, amount`
`stx_lock`	`stx_lock_event`	`locked_address, locked_amount, unlock_height`
`ft_transfer`	`ft_transfer_event`	`asset_identifier, sender?, recipient?, amount`
`ft_mint`	`ft_mint_event`	`asset_identifier, recipient?, amount`
`ft_burn`	`ft_burn_event`	`asset_identifier, sender?, amount`
`nft_transfer`	`nft_transfer_event`	`asset_identifier, sender?, recipient?, raw_value`
`nft_mint`	`nft_mint_event`	`asset_identifier, recipient?, raw_value`
`nft_burn`	`nft_burn_event`	`asset_identifier, sender?, raw_value`
`print_event`	`contract_event`	`topic, contract_identifier, value, raw_value`

Three traps in this table

Fields marked ? are omitted entirely when not applicable, and JSON.stringify drops them. A stx_mint delivery has no sender key at all; it is never sent as sender: null.
NFT deliveries carry only raw_value (canonical hex of the token-id Clarity value). There is no decoded value field on nft_* events.
print_event's delivered event.type is the node's raw name contract_event, not print_event_event. Its contract field is contract_identifier, not contract_id.

"event": {
  "type": "contract_event",
  "event_index": 0,
  "tx_id": "0x…",
  "data": {
    "topic": "print",
    "contract_identifier": "SP….registry",
    "value": { "updated": true },
    "raw_value": "0x0c00000001…"
  }
}

Tx-level triggers: `contract_call` / `contract_deploy`

data.event is flat, with no nested .data:

"event": {
  "tx_id": "0x…",
  "type": "contract_call",
  "sender": "SP…",
  "status": "success",
  "contract_id": "SP….amm",
  "function_name": "swap-x-for-y",
  "function_args": ["0x0100000000000000000000000000002710"],
  "result_hex": "0x0703"
}

function_args are raw hex

function_args are RAW, undecoded Clarity-value hex strings in call order, so decode them yourself with decodeClarityValue from @secondlayer/sdk. For a contract_deploy trigger, event.type is smart_contract (the underlying Stacks tx type) rather than contract_deploy, and function_name/function_args/result_hex are all null (no function call to report).

sBTC triggers

The five sBTC triggers deliver a flat, already-typed event keyed by topic:

"event": {
  "topic": "completed-deposit",
  "request_id": 42,
  "sender": "SP…",
  "amount": "5000000",
  "bitcoin_txid": "…",
  "block_height": 123456,
  "tx_id": "0x…"
}

topic is completed-deposit, withdrawal-create, withdrawal-accept, withdrawal-reject, or withdrawal-swept-confirmed. The settlement event instead carries sweep_txid, btc_confirmations, btc_block_height, confirmed_at, amount, sender, with no bitcoin_txid/block_height/tx_id.

Event shapes

Event-level triggers

Tx-level triggers: contract_call / contract_deploy

sBTC triggers

Tx-level triggers: `contract_call` / `contract_deploy`