Subscribe updates

JSON API AsyncAPI›/v2/updates›subscribe

/v2/updates

Subscribe updates

WebSocketSince 3.4Changed 3.5

SUBSCRIBE/v2/updates

Protocol Details

Inputs

Outputs

The server streams a sequence of Either_JsCantonError_JsGetUpdatesResponse messages. Each message is one of:

Success — a JsGetUpdatesResponse containing a single update:

{
  "update": <Update>
}

where <Update> is one of:

Variant	Key	Description
Transaction	"Transaction"	A committed ledger transaction
OffsetCheckpoint	"OffsetCheckpoint"	An offset checkpoint (no transaction, used to track progress)
Reassignment	"Reassignment"	A contract reassignment between synchronizers
TopologyTransaction	"TopologyTransaction"	A topology change (party or key update)

Example success message:

{
  "update": {
    "Transaction": {
      "updateId": "<string>",
      "commandId": "<string>",
      "workflowId": "<string>",
      "effectiveAt": "<timestamp>",
      "offset": "<string>",
      "events": [],
      "synchronizerId": "<string>",
      "traceContext": {}
    }
  }
}

Error — a JsCantonError with fields code, cause, context, and errorCategory (documented below).

Either_JsCantonError_JsGetUpdatesResponse

codestring

causestring

contextobject

errorCategorystring

Lifecycle Changes

3.5channel description updated; publish description updated; publish required fields added: beginExclusive; publish required fields removed: updateFormat; subscribe description updated

Related Schemas

Either_JsCantonError_JsGetUpdatesResponse

codestring

causestring

contextobject

errorCategorystring

wscat

wscat

npx wscat -c <WEBSOCKET_URL>

messageapplication/json

message

{
  "code": "<string>",
  "cause": "<string>",
  "context": {},
  "errorCategory": "<integer>"
}