thalos-docs/docs/api/messages.md

Messages

This document describes the message payloads published by Thalos.

Encoding

Thalos supports two codecs (configured via message_codec / --codec):

• json (default)
• msgpack

When using JSON:

• []byte fields are base64-encoded strings
• timestamps are UTC and serialized by the JSON codec

Message types

HeartBeat

Published on heartbeat channel periodically.

Field	Type	Description
blocknum	uint32	Current block number
head_blocknum	uint32	Current chain head block number
last_irreversible_blocknum	uint32	Last irreversible block number

TransactionTrace

Published on transactions channel (unless disabled).

Field	Type	Description
id	string	Transaction id
blocknum	uint32	Block number
blocktimestamp	time	Block timestamp
status	string	Transaction status
cpu_usage_us	uint32	CPU usage (microseconds)
net_usage_words	uint32	NET usage words
elapsed	int64	Execution time
net_usage	uint64	NET usage
scheduled	bool	Scheduled transaction flag
action_traces	ActionTrace[]	Action traces for this transaction
except	string	Exception text (if any)
error	uint64	Error code

ActionTrace

Published on actions channels (unless disabled), and also nested in TransactionTrace.action_traces.

Field	Type	Description
tx_id	string	Parent transaction id
blocknum	uint32	Block number
blocktimestamp	time	Block timestamp
receipt	ActionReceipt / null	Action receipt
name	string	Action name
contract	string	Contract account
receiver	string	Receiver account
first_receiver	bool	True if receiver is first receiver
data	any	ABI-decoded action data when available
authorization	PermissionLevel[]	Authorization list
except	string	Exception text (if any)
error	uint64	Error code
return	bytes	Return value bytes

Note: the field is name (not action).

ActionReceipt

Field	Type	Description
receiver	string	Receiver account
act_digest	string	Action digest
global_sequence	uint64	Global sequence
recv_sequence	uint64	Receiver sequence
auth_sequence	AccountAuthSequence[]	Auth sequence list
code_sequence	uint32	Code sequence
abi_sequence	uint32	ABI sequence

PermissionLevel

Field	Type	Description
actor	string	Actor account
permission	string	Permission name

AccountAuthSequence

Field	Type	Description
account	string	Account name
sequence	uint64	Sequence

RollbackMessage

Published on rollback channel on microfork rollback detection.

Field	Type	Description
old_block	uint32	Previous current block
new_block	uint32	New current block

TableDelta

Published on tabledeltas channels (unless disabled).

Field	Type	Description
blocknum	uint32	Block number
blocktimestamp	time	Block timestamp
name	string	SHIP delta name
rows	TableDeltaRow[]	Rows in the delta

TableDeltaRow

Field	Type	Description
present	bool	Row present/removed flag
data	object	Parsed row data when available
raw_data	bytes	Raw row bytes

TableDeltaRowContract (name = contract_row)

For contract_row deltas, data typically contains:

Field	Type	Description
table	string	Table name
scope	string	Table scope
primary_key	string | int	Primary key
code	string	Contract account
payer	string	RAM payer
value	object | base64_string	Decoded row value when ABI is available; otherwise raw bytes

If ABI decode fails, Thalos keeps raw data and may leave decoded fields partial.