# USDC applications on Arc need to budget for randomness as well as gas

Canonical: https://yielddispatch.com/news/c3995a0d-018c-4abd-9cb7-90b1b18884c8
Published: 2026-09-19T15:00:03.874Z
Publisher: Yield Dispatch

An Arc application and an HTTP agent can now reach D20DAO through different payment paths. The contract route has a configurable service fee plus transaction gas. The agent API advertises a fixed 0.05 USDC call price through x402.

*Analysis | Documentation reviewed September 19, 2026.*

An Arc application and an HTTP agent can now reach D20DAO through different payment paths. The contract route has a configurable service fee plus transaction gas. The agent API advertises a fixed 0.05 USDC call price through x402.

The SDK records a September 18 change to Arc Mainnet pricing: a 0.02 USDC minimum, multiplier of three and 300,000-gas fulfillment overhead. Testnet retains the older 0.08 minimum and multiplier of five. Mixing the two produces a misleading budget.

For a 100,000-gas callback, the mainnet formula at an assumed 20-gwei base fee is max(0.02, 3 × 20 × 10^-9 × 400,000), or 0.024 USDC. At an assumed 176 gwei it becomes 0.2112 USDC. These are calculations using documented parameters, not live quotes; transaction gas is additional and pricing can change.

The HTTP API price buys a different service boundary: the provider opens the underlying randomness request. At 0.05 USDC, 100 paid calls have a listed service cost of 5 USDC, before any caller-side Gateway or network costs. One call can return multiple values where the operation allows it, so a die roll and a call are not necessarily the same billing unit.

Applications should decide which outcomes can safely share a request before purchasing them. Onchain fees, API payments and application prizes have separate settlement and refund rules. Quote the intended route instead of assuming a fixed price applies to both.

Sources: [SDK pricing reference](https://github.com/d20dao/d20-sdk#pricing), [agent API guide](https://d20dao.org/docs/agents), [API refund policy](https://d20dao.org/refunds).

Related reading: [D20DAO reports 470 Arc testnet requests completed within its 60-second deadline](https://forkbrief.com/news/82a01df1-4bfc-4ba3-95fa-579f3e2e62f0); [D20DAO adds x402 payments for verifiable randomness at 0.05 USDC per call](https://chainminute.com/news/34c7c5f3-7f68-4b11-ac92-4448ee0028f9).

## Sources

- [D20DAO agent API guide](https://d20dao.org/docs/agents) — D20DAO
- [D20DAO API refund policy](https://d20dao.org/refunds) — D20DAO
- [D20DAO SDK pricing reference](https://github.com/d20dao/d20-sdk) — D20DAO
- [D20DAO reports 470 Arc testnet requests completed within its 60-second deadline](https://forkbrief.com/news/82a01df1-4bfc-4ba3-95fa-579f3e2e62f0) — Fork Brief
- [D20DAO adds x402 payments for verifiable randomness at 0.05 USDC per call](https://chainminute.com/news/34c7c5f3-7f68-4b11-ac92-4448ee0028f9) — Chain Minute

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