Committed before the request.
A published hash-chain commitment fixes the seed in advance. The result mixes it with the request block hash, your contribution and the request context.
Live on Arc mainnet
RUFF
Randomness Utility & Fulfillment Framework
Verifiable randomness for smart contracts.
Give your app a random number with public proof. Request in USDC, receive the result onchain and let anyone verify it.
THE RUFF APPROACH
From commitment to callback.
Checked by the contract.
The hub verifies the seed and computes the result onchain before calling your contract. If your callback fails, the same result stays available to recover.
Open to independent checks.
Follow requests and proofs in RUFF Explorer. Use the public SDK or CLI to check the commitment and recompute a delivered result yourself.
WHAT YOU CAN BUILD
Randomness for your application.
Onchain games
Resolve rounds, loot drops and PvP outcomes with randomness players can check.
Lotteries & giveaways
Draw winners from a fixed entry list, with a public record of the random result.
NFTs & allocations
Shuffle a collection, assign traits or select recipients under rules set by your contract.
INFRASTRUCTURE FOR ARC
An Arc primitive for every builder.
Games and apps on Arc need a way to settle random outcomes transparently. RUFF supplies that shared primitive: request, verification and settlement on the same chain, with fees in native USDC.
Any consumer contract can connect within the published fee and capacity limits. No allowlist or extra service token.
Connect your contractPAY PER REQUEST
0.01333 USDC
Default fee · 100,000 callback gas
1,000 requests = 13.33 USDC
- Onchain proof verification
- Delivery and callback execution
- Public SDK, CLI and explorer
Request transaction gas is separate. Your callback budget affects the fee; quote the current tariff from the hub before sending.
Fees & limitsBUILD WITH RUFF
Everything to get started.
npm install ruff-hub viem