XRPLink

XRPLink — Cryptographically Verified XRP Payment Receipts

Generate tamper-proof, independently verifiable receipts for any XRP payment. XRPLink attests XRP transactions through Flare's FDC protocol and provides a shareable receipt with a cryptographic Merkle proof. Built for compliance, audit, and merchant reconciliation.

Live at https://xrp-link.com

Quick Start

# Visit the hosted app
open https://xrp-link.com

# Or run locally
git clone <repo-url>
cd xrplink
npm install
cp .env.example .env
# Edit .env with your private key and API key
npm run start:rest

Project Status

Live on Flare mainnet. End-to-end pipeline validated: XRP tx → verifier API → FdcHub → DA Layer proof → on-chain verification.

Milestone	Status
Mainnet deployment	✅ Live (PaymentVerifierMainnet at 0xA10034...e14b)
End-to-end pipeline validated	✅ Complete — XRP tx attested on mainnet
User auth (signup/login)	✅ Complete
Receipt pages	✅ Complete — shareable at /receipt/:txHash
Dashboard	✅ Complete — API key, usage stats, receipt history
REST API	✅ Complete — verify, status, webhooks, health
API key auth + rate limiting	✅ Complete
Subscription tiers	✅ Complete — free/paid/pro
MCP Server	✅ Complete — 5 tools, 4 prompts, 5 resources
Hardhat test suite	✅ Complete — 8 tests passing
Open source	✅ BUSL-1.1 (source-available)

Server Modes

Command	What starts
npm start	MCP server (stdio) + REST API
npm run start:mcp	MCP server only
npm run start:rest	REST API only

Tech Stack & Dependencies

Dep	Version	Purpose
hardhat	^3.9.1	Solidity dev environment
ethers	5.8.0	EVM interaction
tsx	^4.23.0	TypeScript script runner
dotenv	^17.4.2	.env config
express	^5.2.1	HTTP API server
@flarenetwork/flare-periphery-contracts	^0.1.52	FDC protocol interfaces
@modelcontextprotocol/sdk	^1.29.0	MCP server framework

API Endpoints

Method	Path	Auth	Description
POST	/auth/signup	Public	Create account + free API key
POST	/auth/login	Public	Log in and get a session token
GET	/me	Bearer token	Current user info and API keys
GET	/health	Public	Server status and network info
GET	/dashboard	Public	HTML user dashboard
GET	/receipt/:txHash	Public	View a receipt (HTML)
POST	/api/v1/verify/xrp-payment	API key	Attest an XRP tx
GET	/api/v1/status/:id	API key	Check attestation by UUID
GET	/api/v1/status-by-tx/:txHash	API key	Check attestation by txHash
POST	/api/v1/webhooks	API key	Register webhook callback
POST	/billing/subscribe	Bearer token	Upgrade subscription
GET	/billing/portal	Bearer token	Manage billing
GET	/mcp/resources	Public	List MCP resources
GET	/mcp/prompts	Public	List MCP prompts

MCP Tools

Tool	Description
verify_xrp_payment	Submit txHash for FDC attestation
get_attestation_status	Check attestation by UUID
lookup_attestation_by_tx	Find attestation by txHash
get_attestation_by_round	List attestations by round ID
get_server_info	Server + network info

Connect via stdio: npm run start:mcp

Network Configuration

Param	Coston2 (Testnet)	Flare Mainnet
RPC	https://coston2-api.flare.network	https://flare-api.flare.network
Chain ID	114	14
FdcHub	0x48aC463d7975828989331F4De43341627b9c5f1D	0xc25c749DC27Efb1864Cb3DADa8845B7687eB2d44
FdcVerification	0x906507E0B64bcD494Db73bd0459d1C667e14B933	0x9394c7A36b3Da8de1b4F27cdD0a554dA4Fa7132d
DA Layer	https://ctn2-data-availability.flare.network	https://flr-data-availability.flare.network
Verifier API	https://fdc-verifiers-testnet.flare.network	https://fdc-verifiers-mainnet.flare.network
Source ID	testXRP	XRP
First Voting Round	1658430000	1658430000
Attestation fee	1 test FLR	20 FLR

Architecture

┌───────────────────────┐
│     User dApp         │  (Flare EVM)
│  (PaymentVerifier.sol)│
└────────┬──────────────┘
         │ verifyXRPPayment(proof)
         ▼
┌───────────────────────┐
│  FdcVerification      │  (enshrined FDC protocol contract)
│  (via ContractRegistry)│
└────────┬──────────────┘
         │
    ┌────┴────┐
    │ DA Layer│──── Proof + response
    └────┬────┘
         │
    ┌────┴────┐
    │ Verifier│──── ABI-encoded request with MIC
    └────┬────┘
         │
    XRP Testnet / Mainnet

Key data flow:

1. XRP tx happens on XRP Ledger
2. Verifier API fetches tx details, computes MIC, returns ABI-encoded request
3. Request submitted to FdcHub on Flare with FLR fee
4. FDC providers independently verify the XRP tx, reach consensus (90s round)
5. Merkle root stored onchain via Relay contract
6. DA Layer serves attestation response + Merkle proof
7. Smart contract verifies proof against onchain Merkle root via FdcVerification

Contributing

See CONTRIBUTING.md. All contributions welcome — bug fixes, feature requests, docs improvements, and test additions.

XRPLink is source-available (BUSL-1.1) and built for the Flare ecosystem. Non-commercial use, evaluation, and personal use are free. Running XRPLink as a commercial service requires a license from the Licensor.

License

BUSL-1.1 — see LICENSE. Converts to MIT after four years.