title: What is CardZero description: "Open infrastructure for AI agent payments, identity, reputation, and escrow."

CardZero is the settlement layer for the agent economy.

When an AI agent needs to pay for something — an API call, a data feed, another agent's work — it can't use a credit card (no human in the loop), can't use a crypto wallet directly (key management, gas, complexity), and can't use Stripe (designed for humans). CardZero closes that gap.

The problem we solve

A real-world AI agent today wants to:

1. Pay for things autonomously — APIs, data, content, compute. Without asking for permission on every $0.001 charge.
2. Hire other agents — when one agent doesn't have a capability another does, they should be able to transact directly under "pay-on-delivery" terms.
3. Prove reputation — an unknown agent claiming "I'm reliable" doesn't prove anything. A signed on-chain track record does.
4. Stay within bounds — the human owner needs to set limits the agent physically cannot exceed (not "shouldn't" — can't).

CardZero gives agents all four, in one stack, on Base mainnet, with no token required.

The stack

┌──────────────────────────────────────────────────────────┐
│  Application: your agent                                  │
├──────────────────────────────────────────────────────────┤
│  Service:   x402  ·  A2A direct  ·  A2A escrow            │
├──────────────────────────────────────────────────────────┤
│  Identity:  ERC-8004 IdentityRegistry                     │
│  Reputation: ERC-8004 ReputationRegistry                  │
├──────────────────────────────────────────────────────────┤
│  Money:     ERC-4337 wallet  ·  USDC                      │
├──────────────────────────────────────────────────────────┤
│  Chain:     Base L2 (Coinbase)                            │
└──────────────────────────────────────────────────────────┘

Each layer is a public standard. Each is independently useful. You can use just the wallet (skip escrow), just escrow (skip reputation), just the reputation lookup (no payment), or all of it.

Who's it for

Design principles

• Open standards over proprietary protocols. ERC-4337, ERC-8004, ERC-8183, x402. All public, all portable.
• No token gate. Anyone can use CardZero. No $CARD, no airdrop, no governance.
• Owner stays in control. Spending rules enforced at the smart-contract level, not in our API. We can't override them.
• Composable, not monolithic. Use one capability or all four. Mix with other protocols freely.
• Boring infrastructure. We don't ship "AI features." We ship a payments stack that happens to work for agents because it works for everyone.

What CardZero is not

• Not a token launch. No $CARD, no governance, no points-farm. Ever.
• Not a custodian. Your wallet is a smart contract owned via your account. We facilitate execution; we can't move funds without you.
• Not an agent marketplace / discovery layer. Other projects are doing that better; CardZero is the layer below.
• Not a multi-chain solution (yet). Base only. Covers ~90% of agent payment volume today; we'd rather do one chain well than many chains poorly.
• Not legal or financial advice. Beta. Audit in progress. Use accordingly.

How it stays open

• All standards are public EIPs — anyone can implement, fork, compete.
• Smart contract source is public at github.com/mrocker/CardZero.
• OpenAPI spec describes every endpoint; openapi.yaml.
• MCP server is MIT-licensed at npm: cardzero-mcp.
• Reputation is queryable by anyone at GET /v1/reputation/{walletAddress}.

If we ever stop existing, your wallet keeps working — it's a smart contract on Base, not on our servers. Reputation events are on-chain, queryable forever.

Live mainnet proof

The first 1 USDC end-to-end Job lifecycle on Base mainnet: