Scan API for Current State of CC and Synchronizer Traffic

Open and issuing mining rounds, traffic status, and conversion rates

Alongside information about the overall Splice network operations, Scan provides some more specific details about current Amulet-related network state.

Validator Traffic Credits and Purchases

Sequencing messages on the global synchronizer, which is an integral part of the Canton commit protocol for Daml transactions and validator operations more generally, costs traffic fees purchased in Amulet. /v0/domains//members//traffic-status can be used to query the purchased and spent traffic credit.

Here’s an example response from querying for a member participant.

{
  "traffic_status": {
    "actual": {
      "total_consumed": 0,
      "total_limit": 6000000
    },
    "target": {
      "total_purchased": 6000000
    }
  }
}

total_limit is the most important statistic; total_purchased is usually the same, but may be higher if a purchase is still in process.

Open Mining Rounds

Amulet activity and traffic are associated with rounds, which determine how rewards are allocated. To check on the current rounds available for traffic or with rewards currently in process, check /v0/open-and-issuing-mining-rounds.

This endpoint features a parameter for more efficient polling; see the MaybeCachedContractWithStateMap OpenAPI specification for more details. The initial request is always empty:

{
  "cached_open_mining_round_contract_ids": [],
  "cached_issuing_round_contract_ids": []
}

This might respond with something like

{
  "time_to_live_in_microseconds": 600000000,
  "open_mining_rounds": {
    "00dea42d6e8aa5cdd8110564774b740943c2f0d57ecef624f2f9ab881a847f3ebfca1012200109878982101a4f2b8106091bdde79793daf8548662f9962b371adc8c3aa294": {
      "contract": {
        "template_id": "979ec710c3ae3a05cb44edf8461a9b4d7dd2053add95664f94fc89e5f18df80f:Splice.Round:OpenMiningRound",
        "contract_id": "00dea42d6e8aa5cdd8110564774b740943c2f0d57ecef624f2f9ab881a847f3ebfca1012200109878982101a4f2b8106091bdde79793daf8548662f9962b371adc8c3aa294",
        "payload": {
          "dso": "DSO::122084177677350389dd0710d6516f700a33fe348c5f2702dffef6d36e1dedcbfc17",
          "tickDuration": {
            "microseconds": "600000000"
          },
          "issuingFor": {
            "microseconds": "12474000000000"
          },
          "amuletPrice": "0.005",
          "issuanceConfig": /* ... */,
          "opensAt": "2025-02-18T22:18:42.495769Z",
          "transferConfigUsd": {
            "holdingFee": {
              "rate": "0.0000190259"
            },
            /* other configuration */
          },
          "targetClosesAt": "2025-02-18T22:38:42.495769Z",
          "round": {
            "number": "20790"
          }
        },
        /* other contract metadata */
      },
      "domain_id": "global-domain::122084177677350389dd0710d6516f700a33fe348c5f2702dffef6d36e1dedcbfc17"
    },
    /* other open rounds; there are usually 3 */
  },
  "issuing_mining_rounds": {
    "00f15ce85311175cc62acab235d768f5c8b1e02247a1d0e4c54635fc2b43726262ca101220cc210224ad72ee4a71ae887732898f0f1db81e530b3817e75500ebe5a8a4f7a6": {
      "contract": {
        "template_id": "979ec710c3ae3a05cb44edf8461a9b4d7dd2053add95664f94fc89e5f18df80f:Splice.Round:IssuingMiningRound",
        "contract_id": "00f15ce85311175cc62acab235d768f5c8b1e02247a1d0e4c54635fc2b43726262ca101220cc210224ad72ee4a71ae887732898f0f1db81e530b3817e75500ebe5a8a4f7a6",
        "payload": {
          "dso": "DSO::122084177677350389dd0710d6516f700a33fe348c5f2702dffef6d36e1dedcbfc17",
          "optIssuancePerValidatorFaucetCoupon": "324.0134341208",
          "issuancePerFeaturedAppRewardCoupon": "100.0",
          "opensAt": "2025-02-18T22:29:35.850299Z",
          "issuancePerSvRewardCoupon": "0.4058853374",
          "targetClosesAt": "2025-02-18T22:49:35.850299Z",
          "issuancePerUnfeaturedAppRewardCoupon": "0.6",
          "round": {
            "number": "20788"
          },
          "issuancePerValidatorRewardCoupon": "0.2"
        },
        /* other contract metadata */
      },
      "domain_id": "global-domain::122084177677350389dd0710d6516f700a33fe348c5f2702dffef6d36e1dedcbfc17"
    },
    /* any other issuing rounds */
  }
}

Key fields in the contract.payload of open and issuing mining rounds are round, opensAt, and targetClosesAt, which gives you an idea of the open window for the round. Open rounds also include many fields explaining the assigned fees for that round; see the Daml template OpenMiningRound for more details. For followup polling requests, you’ll want to pass the keys from the previously-returned maps so Scan responds more efficiently.

Conversion rate

The conversion rate for Amulet to USD is set for an open round. The conversion rate is found in the amuletPrice field in the contract.payload of an open round. In the example above, the conversion rate is 0.005 USD per Amulet.

Closed Mining Rounds

/v0/closed-rounds is more niche than Open Mining Rounds; it usually yields an empty response. However, it can yield some ClosedMiningRound Daml contracts if there are unclaimed rewards for that round, or a final confirmation for the round closure hasn’t been created yet; as validators operate asynchronously around the Daml ledger to complete these operations, this can be briefly true, but ideally for as short a time as possible.