RailSplit

RailSplit is a Next.js app for Flare Testnet Coston2. A merchant publishes a payment link priced in US dollars, and a customer pays it in the network's native coin (C2FLR) at the live FTSOv2 FLR/USD rate, all onchain.

• A merchant sets a dollar price, publishes one link, and the settlement lands directly in their connected wallet.
• The conversion happens inside the contract against the live feed at payment time, so no one can pay at a stale or self-chosen rate.
• Customers send the quoted coin amount plus a small buffer; the contract refunds the surplus in the same transaction.
• A link is single use and closes itself once a payment settles. If the feed is more than 300 seconds old, the payment is rejected rather than settled at an old rate.
• Settlement history is stored onchain (not just emitted) and read back in pages, so the dashboard works on public RPC infrastructure.

Live demo: https://railsplit.vercel.app

What the app has

• Public home page
• Docs page
• Merchant dashboard with settlement metrics, payment links, and a live onchain ledger
• Payment link creation page with live quote preview and QR/share after publishing
• Public checkout page with live quoting and readable contract errors
• Customer receipt page (download as JPEG, view on explorer)
• "My receipts" history on the payer's device
• QR share dialog for existing links

Stack

• Solidity 0.8.25 with FTSOv2 through @flarenetwork/flare-periphery-contracts
• Next.js 16
• React 19
• Tailwind CSS 4
• Wagmi
• Viem
• Flare Testnet Coston2

Run the app

1. Install packages at the repo root:

   npm install

2. Start the app:

   npm run dev

3. Open http://localhost:3000.

Check the app

npm run lint
npm run build

Main routes

• / - public home page
• /docs - product docs
• /dashboard - merchant dashboard
• /dashboard/links/new - new payment link form
• /pay/[slug] - public checkout page
• /pay/[slug]/receipt?tx=<hash> - customer receipt for a settled payment
• /receipts - receipts history saved on this device

Chain data

RailSplit runs on Flare Testnet Coston2 (chain 114).

• RPC: https://coston2-api.flare.network/ext/C/rpc
• Explorer: https://coston2-explorer.flare.network
• Faucet: https://faucet.flare.network/coston2

The deployed contract address is written to src/lib/contract-address.ts by the deploy script.

Contract workspace

The contract code is in contracts/. It is a separate Hardhat project.

1. Install contract packages:

   cd contracts
   npm install

2. Compile the contract:

   npm run compile

3. Write the ABI file used by the app:

   node scripts/write-abi.js

4. Set DEPLOYER_PRIVATE_KEY in your shell, then deploy:

   npm run deploy:coston2

The deploy script deploys RailSplitPay, seeds sample links, and writes the new contract address into the Next.js app.

Deploy the app

Build the root app with npm run build, then deploy it to any host that supports Next.js 16.

If the contract address changes, rerun the contract deploy script, rewrite the ABI, and rebuild the app.