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Alfred Zhang
Alfred Zhang

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How We Built a Card Network That Settles on Base L2 (No Banks Required)

Australia just banned card surcharges. The Reserve Bank says consumers will save $1.6 billion a year.

But here's what the headlines miss: the cost doesn't disappear. It shifts. Merchants still pay 0.3-0.8% on every tap. They just can't pass it on anymore. Banks warned they'll cut rewards and raise fees.

We decided to remove the cost instead of hiding it.

What is OpenPasskey?

A new payment network. Same EMV contactless standard as Visa and Mastercard. Same tap at the terminal. But no bank, no card network, no interchange fee.

We secured our own Issuer Identification Number (IIN) from ISO. That's the same identifier system Visa and Mastercard use. Any acquirer can add us to their routing table in about a day. Merchants change nothing.

The Technical Stack

The Card: Custom Java Card applet on a JCOP4 chip. P-256 ECDSA signatures (the same elliptic curve used in modern EMV chip cards, and cryptographically stronger than Visa's legacy 3DES).

On-Chain Verification: P-256 signature verification via the RIP-7212 precompile on Base L2. This lets us verify the card's cryptographic signature on-chain at minimal gas cost.

Settlement: ClearingVault contract with per-merchant CREATE2 receivers. Regulated AUD stablecoins. Settlement in seconds, not the 2-3 business days Visa takes.

Three Payment Methods:

  1. Physical EMV card tap (Java Card NFC applet)
  2. Mobile phone tap (Host Card Emulation / HCE)
  3. QR scan from any wallet (ERC-681 standard)

All three settle through the same on-chain pipeline.

How a Card Payment Actually Works

When you tap your Visa card at a cafe:

  1. Your bank (issuer) authorizes the transaction
  2. Visa's network routes it
  3. The cafe's bank (acquirer) receives the funds
  4. Interchange fee goes to your bank (0.3-0.8%)
  5. Scheme fee goes to Visa
  6. Merchant service fee goes to the acquirer

By the time the cafe gets paid (2-3 days later), they've lost a percentage of every transaction.

When you tap an OpenPasskey card:

  1. Card signs the transaction with P-256
  2. Signature verified on-chain via RIP-7212
  3. AUD stablecoin transfers to merchant's receiver
  4. Merchant gets AUD in their bank account

No intermediaries. No interchange. No 2-3 day wait.

The Numbers

  • 3,200+ wallet users across 20+ Sydney cafes
  • 45,509 total transactions
  • AU$66,000 volume
  • 4.5x industry average week-12 retention
  • Built by 3 people in 10 months
  • Zero external funding

Selected for Blackbird Giants Cohort 11 (Australia's largest VC, backed Canva in its earliest days). Base ecosystem grant recipient.

Why This Matters for Developers

If you're building on Base or working with stablecoins, this is what real-world payment infrastructure looks like:

  • RIP-7212 makes P-256 verification viable on-chain (critical for EMV card integration)
  • CREATE2 enables deterministic merchant receiver addresses
  • ERC-681 provides a standard QR payment URI scheme

The EMV standard is the key unlock. There are 11+ billion EMV cards in circulation. Any infrastructure that speaks EMV can integrate with existing terminals without merchants changing anything.

What's Next

The RBA is planning a mid-2026 consultation on mobile wallets, BNPL, and e-commerce platforms. We'll be submitting a formal response.

If you're interested in the protocol details or want to build on top of it: openpasskey.com

Twitter: @OpenPasskey


Victor Zhang is co-founder of OpenPasskey. He co-invented ERC-5169 and ERC-7738, co-founded AlphaWallet, and has spent 8 years building on Ethereum.

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