x402 buyer agent · live on Arc mainnet

Which paid APIs actually deliver?

Obol holds a USDC budget and pays x402 services per call on Arc. It scores what comes back, moves its spend to the sellers that deliver, stops paying the ones that fail, and writes every verdict, with the payment evidence, to a public registry other agents can check before they pay.

See the verdicts Registry on explorer Source Sell x402 on Arc? Get scored

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Sellers scored

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Calls behind the scores

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Active / retired

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Last verdict on-chain

Verdicts on Arc

Read live from the registry contract, in your browser. Each score links to the registry write and to the payment it was based on.

75+ delivers 50–74 mixed under 50 not worth paying Score = delivery, completeness, latency and, for chain data, freshness against the live Arc head.

How a verdict is made

Every step runs on Arc mainnet with real USDC. Nothing on this page is simulated.

Ask

The agent calls a paid API. The seller answers HTTP 402 with a price, a recipient and the Arc USDC contract.

Pay

The sidecar checks the seller is allowlisted, the recipient is pinned and the price is under the caps, then pays in USDC by EIP-3009 or Circle Gateway.

Score

It grades the response: arrived, complete, fast, and for chain data how far behind the Arc head it is. A Thompson-sampling allocator shifts budget to value per USDC.

Publish

The score goes to the ReputationRegistry with its evidence: an Arc tx hash, a Gateway transfer id, or proof nothing was charged.

Why it can't overspend

One key holder. Only a local sidecar signs payments; the scoring brain never sees the key.
Allowlist and pinned recipients. Unknown sellers and changed payTo addresses are refused.
Arc and USDC only. Any other chain or asset in a 402 challenge is rejected.
Per-call and lifetime caps. The lifetime cap is persisted, so a restart doesn't reset it.
One payment in flight. No double spends from parallel requests.

What Arc does here

USDC settlement. Every paid call settles on Arc, over both Circle rails: EIP-3009 and Gateway.
USDC as gas. A score write costs about 0.001 USDC on mainnet, cheap enough to publish every verdict.
Sub-second finality. A verdict is final before the next purchase decision.
ERC-8004 identity. Registered in the canonical IdentityRegistry on Arc.
CCTP v2. The agent is funded from Base with Circle's Bridge Kit.

Check it yourself

You don't need to trust this page. Read the same data with Foundry: