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Computation charges combine the Cluster’s base price, an optional priority price, and a fixed reserve for submitting the callback transaction.

Base pricing

Each Cluster has a base price per Computation Unit (CU). The program multiplies this price by the Computation Definition’s CU amount and rounds down to lamports.

Computational units

The execution cost of a computation is measured in CUs. The Computation Definition stores the CU amount used for pricing. The cost per CU is determined for each epoch through a voting process. Node Operators cast one vote per Arx node to decide the price of a CU in the upcoming epoch. Abstaining counts as a vote for maintaining the current price. Voting authority belongs to each Arx node’s Node Operator. The resulting CU price becomes the Cluster’s base price for the next epoch. Customers can add a priority price when commissioning a computation.

Priority fee markets

Priority prices raise a computation’s position in its Cluster’s mempool. Queued computations remain subject to the mempool’s 180-slot expiry. Priority-fee ordering is scoped to the Cluster’s mempool. Computations compete only with other computations queued for the same Cluster, which prevents unrelated tasks from interfering with resource allocation. When a valid leader choice is available, it can take one dispatch slot. Otherwise the program uses priority-fee and account-lock ordering. See Leader weight.

Economic incentives for Arx nodes

Base and priority charges contribute to computation revenue. The program allocates this revenue to Cluster members, Recovery Peers, and the protocol fee pool as described in Fee allocation. Stake lockups commit Node Operators and delegators for a minimum period.

Cluster-level competition

Fee competition is local to a Cluster. Computations in different Clusters have independent fee markets.

How customers optimize costs

The customer charge includes:
  • The Cluster’s base price multiplied by the computation’s CU amount
  • The selected priority price multiplied by the computation’s CU amount
  • Callback priority cost based on the callback compute budget
  • A fixed callback submission reserve that scales with the Cluster’s Arx node count
Computation Customers can optimize their costs by carefully managing execution parameters:
  1. Choose submission timing: Submit non-urgent work when demand is lower.
  2. Set the priority price: Increase it when queue position matters, while accounting for the callback compute budget.