PayProof

Create invoices, verify Stellar payments, and generate shareable receipts.

Live: payproof-five.vercel.app  ·  CI:  ·  License: MIT

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Screenshots

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Why I built this

I kept running into the same problem: someone would send a Stellar payment and the other party wanted proof it went through, but pointing them at a block explorer felt like handing someone a raw API response. I wanted something that looked like an actual receipt — something you could print or forward in an email without explanation. PayProof started as a weekend script and turned into this.

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What it does

PayProof has two main flows:

Invoices — create an invoice with a title, amount (XLM or USDC), and your Stellar address. Share the payment link with your client. They see how much to send, to which address, and which memo to include. When they pay, you click "Check for payment" and PayProof queries the Horizon API to confirm it.

Verification and receipts — paste any Stellar transaction hash, choose mainnet or testnet, and PayProof fetches the details from the Horizon API — status, ledger, fee, payment operations (sender, receiver, amount, asset). From there you can generate a receipt page at a stable URL you can print, save as PDF, or share.

Everything runs in the browser. No backend, no data stored server-side, no accounts.

Quick test — paste this testnet hash on the live site:

980a03a11a6e212ac2d6a739188c89437f9cfb1b0302b8aeb58c573a06ef71d4

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Development status

Feature	Status
Invoice creation (/invoice/create)	✅ done
Shareable invoice page (/invoice/[id])	✅ done
Payment detection via Horizon API	✅ done
Invoice list (/invoice)	✅ done
USDC asset support	⚠️ testnet only for now
SEP-7 payment links	✅ done
Transaction verification (mainnet + testnet)	✅ done
payment, path_payment_strict_receive, path_payment_strict_send	✅ done
Receipt pages at /receipt/{hash}-{index}	✅ done
Fee in XLM and stroops	✅ done
QR code on receipts	✅ done
PDF export	✅ done
Print-friendly layout (dark mode safe)	✅ done
JSON export	✅ done
Light/dark theme	✅ done
Responsive mobile layout	✅ done
Network encoded in receipt URL	✅ done (v0.1.1)
Verify page URL state	✅ done (v0.1.1)
path_payment amount resolution	⚠️ open (issue #4)
Test suite	❌ not yet (issues #5, #6)

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Architecture

Browser
  │
  ├── /verify         Hash input + NetworkSelector
  │     │
  │     └── lib/stellar.ts (StellarService)
  │           │
  │           ├── horizon.stellar.org          (mainnet)
  │           └── horizon-testnet.stellar.org  (testnet)
  │
  ├── /invoice/[id]   Invoice view + payer view
  │     │
  │     ├── lib/sep7.ts (buildInvoiceSep7Uri)
  │     │     └── components/pay-with-wallet-button.tsx
  │     │
  │     └── lib/invoices.ts (payment detection)
  │
  └── /receipt/[id]   Parses {hash}-{operationIndex} from URL
        │
        └── components/receipt-card.tsx
              ├── ReceiptQRCode  (qrcode → canvas)
              └── PDF export     (html2canvas + jsPDF, loaded lazily)

Key files:

File	What it does
lib/stellar.ts	Horizon queries, operation filtering, fee conversion
lib/sep7.ts	SEP-7 URI builder (buildSep7PayUri, buildInvoiceSep7Uri)
types/stellar.ts	Shared TypeScript interfaces for Stellar types
types/sep7.ts	SEP-7 types, network passphrases, USDC issuer constants
components/pay-with-wallet-button.tsx	"Pay with Wallet" button that opens a SEP-7 URI
components/transaction-results.tsx	Displays verification results
components/receipt-card.tsx	Receipt layout, PDF export, QR code, share/print
components/receipt-qrcode.tsx	Renders a QR code canvas from a URL
app/receipt/[id]/page.tsx	Loads receipt data from URL, handles network detection

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Running locally

git clone https://github.com/PayProofLabs/payproof.git
cd payproof
npm install
npm run dev

App runs at http://localhost:3000. No environment variables required — defaults to testnet.

To default to mainnet, create .env.local:

NEXT_PUBLIC_STELLAR_NETWORK=mainnet

Available commands:

npm run dev          # development server with HMR
npm run build        # production build
npm run start        # serve production build
npm run lint         # ESLint
npm run type-check   # tsc --noEmit
npm test             # run unit tests (vitest)

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Stack

• Next.js 15 (App Router, client components for Horizon queries)
• TypeScript
• Tailwind CSS + shadcn/ui (Radix primitives)
• @stellar/stellar-sdk — Horizon.Server client and hash validation
• qrcode — QR code generation to canvas
• jspdf + html2canvas — client-side PDF export (lazy-loaded)
• next-themes — light/dark mode

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Contributing

Quick start

git clone https://github.com/PayProofLabs/payproof.git
cd payproof
npm install
cp .env.example .env.local
npm run dev

The app talks directly to the Stellar Horizon API from the browser. No backend to run, no API keys needed. Defaults to testnet.

Picking something to work on

The issues in .github/ISSUES.md are written to be directly actionable — each one has acceptance criteria, the files you'll need to touch, and what the reviewer will check. They're labelled by complexity:

• Trivial — under an hour, good for a first PR: issues #3, #7, #10, #11, #12, #14, #15
• Medium — half a day, some design decisions involved: issues #1, #2, #4, #5, #6, #8, #9, #13
• High — full day+, coordinate in an issue first before starting

If you want to work on something, leave a comment on the issue so others know it's taken.

Workflow

1. Fork, then git checkout -b fix/brief-description
2. Make the change. Keep commits focused — one logical change per commit.
3. Run npm run lint && npm run type-check before pushing.
4. If the change touches verification or receipts, test it against a real testnet transaction.
5. Open a PR. The template will prompt you for what to include.

Commit style: fix: correct fee display, feat: encode network in receipt URL, docs: add memo_type to contributing guide.

Good to know before diving in

Some non-obvious things about this codebase:

• transaction.ledger in the Stellar SDK is a function, not a value. The sequence number is at transaction.ledger_attr. Using String(transaction.ledger) produces [Function (anonymous)].
• All Stellar queries happen in the browser — there's nothing server-side to worry about.
• The receipt/[id] page is a client component that fetches on mount. It guesses the network (testnet-first) because the network isn't in the URL yet — fixing that is issue #1.
• PDF export (html2canvas + jsPDF) is lazy-loaded so it doesn't bloat the initial bundle. The dynamic imports are in receipt-card.tsx.

See CONTRIBUTING.md for the full setup guide including how to get a testnet transaction to work with.

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Roadmap

See ROADMAP.md for what's planned and why.

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License

MIT — see LICENSE.

PayProof is an independent project and is not affiliated with the Stellar Development Foundation.