Payproof — Invoices & Verifiable Receipts

Our app is built on Arc.

Payproof turns any wallet address into an invoicing tool. Create a stablecoin invoice, share it as a link or QR code, receive USDC or EURC, and hand your client a receipt that anyone can verify independently onchain.

Why it's different

• Serverless by design. The entire invoice travels inside the shareable link (base64url-encoded in the URL fragment). No database, no accounts, no backend to shut down — host the single HTML file anywhere and it runs forever.
• Onchain payment references. Every invoice is fingerprinted with a unique micro-amount signature in the final decimals (e.g. 25.000347) — the onchain equivalent of a bank payment reference. Payproof scans ERC-20 Transfer logs on Arc and matches the payment to the invoice automatically. No oracle, no webhook, no trust.
• Verifiable receipts. Each receipt maps to a transaction hash on Arc. Clients, accountants, or disputes can verify it on any Arc explorer — Payproof even has a standalone "Verify a payment" mode that rebuilds a receipt from any tx hash.
• One-asset UX, unique to Arc. Gas on Arc Network is paid in USDC, so a payer needs exactly one token — no second coin for fees. Fees are dollar-denominated and predictable (~$0.01).
• Self-custodial. Payproof never holds, routes, or controls funds. Payments go wallet-to-wallet.

Network details used

Parameter	Value
Network	Arc Testnet
Chain ID	5042002 (0x4cef52)
RPC	https://rpc.testnet.arc.network (+ Blockdaemon / dRPC / QuickNode fallbacks)
Explorer	https://testnet.arcscan.app
Faucet	https://faucet.circle.com
USDC (ERC-20, 6 decimals)	0x3600000000000000000000000000000000000000
EURC (ERC-20, 6 decimals)	0x89B50855Aa3bE2F677cD6303Cec089B5F319D72a

Run it

It's a single index.html. Options:

Locally — just double-click index.html (an internet connection is needed for the ethers.js CDN and Arc RPC).

GitHub Pages (free, permanent)

1. Create a public repo (e.g. payproof), upload index.html.
2. Settings → Pages → Deploy from branch → main / root.
3. Your app is live at https://<user>.github.io/payproof/.

Vercel / Netlify — drag-and-drop the folder; done in under a minute.

Using it

1. New invoice — enter your receiving address, amount (max 3 decimals; the last 3 decimals are reserved for the reference), currency, description. Generate → share the link/QR.
2. Payer opens the link → one click adds Arc Testnet to MetaMask, connects, and pays the exact amount. Settlement lands in seconds.
3. My invoices — hit Check: Payproof scans Arc transfer logs and flips the invoice to Paid when it finds the exact match, then produces a printable PDF receipt.
4. Verify a payment — paste any Arc tx hash to reconstruct an independent receipt.

Testing end-to-end (testnet)

1. Get testnet USDC from the Circle Faucet (select Arc Testnet).
2. Create an invoice to one of your addresses; open the link in another browser/profile with MetaMask.
3. Pay → watch the invoice flip to Paid → print the receipt.

Compliance & attribution

Payproof is an independent application built on Arc Network ("Arc"). It is not affiliated with, endorsed by, or operated by Circle. Arc is a trademark of Circle Internet Group, Inc. and/or its affiliates. Payproof currently runs on Arc Testnet; testnet tokens have no real-world value.