How zBase compares¶

zBase is the first x402 facilitator that makes agent payments private without giving anything up. The seller is still paid with a completely standard payment, the funds are still compliance-screened, the agent still holds no gas, and it's still one call. Every other approach makes you trade at least one of those away.

Plain-English version: today, when an AI agent pays for an API, the payment is a public receipt — anyone can read the chain and see your wallet paid this API, this much, at this time, forever. zBase makes the same payment work exactly as before for the seller, but the public receipt no longer names you — and it's the first to do that while staying standard, compliant, and gasless.

The one-glance table¶

zBase is the only option that is green across the board. Every other approach is missing at least two of the six.

Approach	Private payer↔payment unlinkable	Standard x402 any CDP seller, unchanged	Compliant ASP, not a blind mixer	Gasless agent holds no ETH	Money-safe no double-pay	Agent-native one call
zBase	✅	✅	✅	✅	✅	✅
Standard x402 facilitator (no privacy)	❌	✅	—	❌	⚠️	✅
One-hop forwarding / stealth address	⚠️	⚠️	❌	❌	⚠️	⚠️
Blind mixer	✅	❌	❌	❌	❌	❌
General privacy system	✅	❌	⚠️	❌	❌	❌

✅ full · ⚠️ partial or caveated · ❌ no · — not applicable. What each approach is, and where it stops, is below.

Where the other approaches stop¶

The standard x402 facilitator (no privacy). What almost every buyer uses today. It settles reliably, but privacy was never a goal: the transaction is a direct, permanent on-chain link from your wallet to the seller you paid. For an agent making hundreds of small calls, that is a complete public spending profile — and the wallet has to hold ETH for gas. zBase keeps the reliability and seller-compatibility (the seller can't tell the difference) and removes the link and the gas.

One-hop forwarding and stealth addresses. These send funds to a fresh address that either forwards them straight to the recipient, or is a per-payment recipient the sender still funds directly. It breaks the direct address-to-address link, and for some uses that is enough. But it is a hop, not an anonymity set, and that is the whole game:

Timing + amount correlation. Money lands in the fresh address and leaves for the recipient in the same instant, for the same amount. An observer watching the sender sees A → fresh → B seconds apart — a speed bump, not a crowd. zBase funds the payer from a shared pool of many independent depositors, and a Groth16 proof hides which deposit funded it. There is no you → payer trail, because the money comes from the pool, not from you.
No compliance gate. A pass-through can't prove funds are not in the known-illicit set. zBase's ASP gives honest users exactly that — the property blind approaches can't offer, and the reason they get sanctioned.

Blind mixers. They hide the link — but with no compliance (honest deposits mix with illicit ones, which is why they get sanctioned) and no x402 rail. Using one means withdrawing to a fresh wallet by hand, funding it with gas, then paying — the agent flow is gone.

General privacy systems (privacy L2s / shielded-transfer protocols). Real privacy for transfers and DeFi, but not x402 payment rails. There is no "pay this API URL and get the data back in one call" — the agent has to bridge assets in, transact, and bridge context back.

Why zBase is first — the technical reasons¶

Private and standard at the same time. The seller is paid by a fresh, single-use wallet that a Groth16 zero-knowledge withdrawal funded from the pool. The seller receives a normal EIP-3009 exact payment and delivers exactly as it would for any standard payment — it never knows zBase was involved. Nothing else gives you unlinkability and works with sellers unchanged. (See How the money flows.)
Compliance-aware privacy, not a blind mixer. zBase is built on the Privacy Pools model: an Association Set Provider (ASP) lets honest users prove their funds are not in the set of known-illicit deposits, without revealing which deposit is theirs. (See The two gates, Trust model.)
Two gates, not one. ASP screens who may withdraw; stealth addresses hide who receives. Two independent mechanisms, so breaking one does not unmask a payment.
Gasless for the agent. A sponsored relayer signs the on-chain settlement, so the agent holds only USDC — never ETH.
Money-safe by construction. The note is spent once: settlement is idempotent, so a dropped response replays the same payment instead of paying twice, and the change note is always seed-recoverable. (See Handling failures safely.)
Built for agents. One SDK call or one MCP command runs the whole loop — free-probe the seller, hit the 402, settle privately, retry with the payment header, return the data. Proven on Base mainnet against real sellers at $0.028, $0.01, and $0.001.

The honest limitation¶

Privacy comes from a crowd: your withdrawal hides among other people's deposits. The pool is still filling toward its launch minimum of 30 independent depositors, so today payments settle and deliver, but they are not crowd-anonymous yet — with a small set an observer could still link a withdrawal to a deposit. Every payment reports this in result.privacy.private. The 30-depositor floor is necessary, not sufficient: even past it, a unique amount or the timing of a withdrawal can narrow the effective set (see the Threat model). We would rather tell you this plainly than overclaim.

Bottom line: zBase is the first and only x402 option that is private, compliance-aware, standard-compatible, gasless, and money-safe in a single agent-native call. See Pay privately in 5 minutes to try it.