Transaction cost visibility

Recomputed on every visit, so this value moves. That movement is how you can tell it reads the validator live, not a fixed number. Press Re-estimate to read it again.

The realized cost reads paid_traffic_cost from a completed transaction's completion. This value is the real cost captured from one controlled, successful execute against our DevNet validator: a self-signatory ValidatorRight create with no value transfer. In that one execute the estimate was 2612 and the actual paid came in at 2577, a little under the estimate, as expected. The page shows this fixed snapshot instead of running an execute for every visitor.

Captured snapshot, one DevNet execute.

Integrating cost visibility

PartyLayer does not own ledger transport. Your dApp supplies a cost-fetcher that calls your validator's /v2/interactive-submission/prepare, typically through your own backend, and PartyLayer provides the types, the TanStack Query wrapper, and the UI:

// 1. Your fetcher returns a CostEstimation (int64 as strings)
const estimate = (signal) => fetchCostEstimate(signal);

// 2. Wrap it in the hook
const { costEstimate, isPending, error } =
  useTransactionCostEstimate({ estimate });

// 3. Render it
<CostPreview estimate={costEstimate} loading={isPending} error={error} />

Cost values are int64 and can exceed Number.MAX_SAFE_INTEGER, so PartyLayer carries them as strings (TrafficCost) end to end. Use trafficCostToBigInt for arithmetic. Set LEDGER_API_URL (plus LEDGER_PARTY, LEDGER_SYNCHRONIZER_ID, LEDGER_DSO_PARTY) to read from a live validator. When unset, the proxy serves a real captured DevNet estimate.