Example for calling /v2/updates/flats?

Questions
1

I’d like to subscribe to transaction events using the Ledger JSON API’s /v2/updates/flats websocket endpoint. Can you give me a sample request payload?

2

The following works using 3.2.0-snapshot.20250206.0. It is likely to change with 3.3+. And eventually the docs will have a sample. But, for now, in bash…

echo '
{
  "verbose": false,
  "beginExclusive": "0",
  "filter": {
    "filtersByParty" : {
      "'${PARTY_ID}'": {
        "cumulative": [
          {
            "identifierFilter": {
              "TemplateFilter": {
                "value": {
                  "includeCreatedEventBlob": false,
                  "templateId": "'${PACKAGE_NAME}':'${MODULE_NAME}':'${ENTITY_NAME}'"
                }
              }
            }
          }
        ]
      }
    }
  }
}
' | jq --compact-output \
  | websocat \
     --header "Authorization: Bearer ${PARTY_TOKEN}" \
     -n1 \
     ws://${LEDGER_HOST}:${LEDGER_JSON}/v2/updates/flats \
  | jq
Sample result 
{
  "update": {
    "Transaction": {
      "value": {
        "update_id": "12201c4cd506a5dd6ddc1723c6a4490eee6cdb80fcc27c3632219e5a76d622a6cbfe",
        "command_id": "somecommandid04",
        "workflow_id": "",
        "effective_at": "2025-05-01T14:43:30.554452Z",
        "events": [
          {
            "CreatedEvent": {
              "event_id": "#12201c4cd506a5dd6ddc1723c6a4490eee6cdb80fcc27c3632219e5a76d622a6cbfe:0",
              "contract_id": "006885c5198349c44273cf1c49895ea16fb81ebcd20496387ff8a2112d5025b9e2ca101220cc5b4f27ec2f13f3bdb7948d96a8f5060f3895bf31018017c93afc49c87d5e42",
              "template_id": "98e04bc228e72e9b21685287533df601555be5513ba1e113cc0b460ca4922a83:Main:Asset",
              "contract_key": null,
              "create_argument": {
                "issuer": "alice::1220869f8fa122836b7410abb29a48d16b4710e28e03f1911fe61ddc80b8977d77c9",
                "owner": "alice::1220869f8fa122836b7410abb29a48d16b4710e28e03f1911fe61ddc80b8977d77c9",
                "name": "my asset",
                "category": "Stock"
              },
              "created_event_blob": "",
              "interface_views": [],
              "witness_parties": [
                "alice::1220869f8fa122836b7410abb29a48d16b4710e28e03f1911fe61ddc80b8977d77c9"
              ],
              "signatories": [
                "alice::1220869f8fa122836b7410abb29a48d16b4710e28e03f1911fe61ddc80b8977d77c9"
              ],
              "observers": [],
              "created_at": "2025-05-01T14:43:30.554452Z",
              "package_name": "ledger-api-samples"
            }
          }
        ],
        "offset": 13,
        "domain_id": "mydomain::12205f417a08971783cd23ea40afc4c98f767229ae3e3bb7018c1cd034521943426c",
        "trace_context": {
          "traceparent": "00-63543e3dbf98217dd7e1d204b9778bb4-9e2b11a4560c0ec4-01",
          "tracestate": null
        },
        "record_time": "2025-05-01T14:43:31.167995Z"
      }
    }
  }
}
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