Kharon Pay Mini
Send crypto to MoMo in seconds.
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描述
KharonPay Mini Description
🚀 Meet KharonPay Mini?
KharonPay Mini is a specialized, feature-complete WhatsApp payment system built for the Rwandan market. It acts as an instant, zero-friction crypto offramp, enabling users to convert their USDT/USDC held on the Starknet blockchain into Rwandan Francs (RWF) and receive the funds directly via their MTN Mobile Money (MoMo) account in seconds.
It is designed to be the fastest, most accessible crypto-to-fiat bridge, bringing the power of account abstraction and decentralized finance to Rwanda's widely-used MoMo ecosystem.
💡 Problem We're Solving
Despite the growth of crypto adoption, users in Rwanda and across Africa face major friction when attempting to spend or cash out their digital assets:
Complex Wallet Management: Traditional crypto wallets are too complex for everyday users.
High Latency Offramp: Converting crypto to local currency often involves long exchange processes on P2P or escrow platforms, high fees, and bank delays.
Lack of Direct Integration: There's a missing direct bridge between decentralized protocols (like Starknet) and dominant local payment methods (like MoMo).
KharonPay Mini solves this by providing a unified system that:
Simplifies Crypto: Uses Account Abstraction (Cartridge Controller) to give users a secure, session-based wallet controlled via their phone number.
Ensures Speed: Provides instant RWF conversion and direct disbursement via the MTN MoMo API.
Offers Accessibility: Puts the entire complex process inside a simple, familiar WhatsApp Bot.
⚙️ How KharonPay Mini Works
The Complete Transaction Flow
Initiation (WhatsApp): The user sends a withdrawal command (e.g., "Withdraw 50 USDT") via the WhatsApp Bot.
API Initialization: The Backend API (Rust) receives the request, gets the real-time exchange rate (USDT to RWF).
Confirmation: The user confirms the withdrawal amount via WhatsApp. This triggers the required crypto transfer from the user's wallet to the blockchain.
On-Chain Monitoring: The Indexer constantly listens to the Starknet blockchain for the
PaymentReceivedevent, extracting the transaction details, user ID, and unique reference.Execution (Atomic Settlement): The Indexer calls the $\text{Backend API}$'s confirm endpoint with a secure HMAC-SHA256 signature.
Disbursement: The {API} verifies the signature, retrieves the pending data, calculates the final RWF amount, and executes the transfer via the MTN Mobile Money Disbursement API.
Finalization: The transaction is recorded in PostgreSQL,and a success message is returned to the WhatsApp user.
🧩 Technical Architecture
Component | Technology | Purpose |
Frontend/Interface | WhatsApp Bot | User-friendly payment initiation and notification. |
Backend Core | Rust (Actix-web) | High-performance API handling security, business logic, and rate calls. |
Blockchain | Starknet (Sepolia) | Used for crypto storage and fast, low-cost settlements (USDT/USDC). |
Account Abstraction | Cartridge Controller | Secure, session-based user wallets managed by phone number. |
Indexing | Apibara Indexer | Real-time monitoring of Starknet events to trigger fiat settlements. |
Fiat Settlement | MTN Mobile Money API | Direct RWF disbursement via OAuth2 and the Disbursement API. |
Database | PostgreSQL | Permanent storage for Users, Wallets, and Transaction history. |
State Management | Redis | Caching of real-time exchange rates and temporary storage of pending transactions. |
Security | HMAC-SHA256 | Signature verification for all internal (indexer) callbacks. |
🌍 Core Features & Accomplishments
Feature | Description | Status |
💸 Instant MoMo Offramp | End-to-end flow from Starknet crypto to RWF in MTN MoMo. | ✅ Complete |
🛡️ Account Abstraction | User-specific Cartridge Controllers with Session Policies for secure execution. | ✅ Complete |
🔐 API Key Security | HMAC-SHA256 verification, API key authentication, and timestamp validation. | ✅ Complete |
💳 Direct MoMo Payout | Full integration with $\text{MTN MoMo}$ for token and status management. | ✅ Complete |
📊 Real-Time Rates | Crypto APIs for accurate USDT to RWF conversion. | ✅ Complete |
📜 Exhaustive Tracking | PostgreSQL schema for users, transactions, and security logs. | ✅ Complete |
📡 Starknet Indexing | Apibara implementation listening for | ✅ Complete |
🔭 Why we are building KharonPay Mini
KharonPay Mini's mission is to remove the complexities of crypto usage, making it as simple as sending a WhatsApp message. By tightly integrating the robust security of Starknet Account Abstraction with the immediate utility of MTN Mobile Money, KharonPay aims to be the leading decentralized offramp for local African currencies, starting with Rwanda. We are building the critical infrastructure to make crypto liquidity invisible and accessible to every mobile user.
本次黑客松进展
The KharonPay project successfully built a complete crypto-to-MoMo offramp system using a **Rust backend** integrated with the **Starknet blockchain** via **Cartridge (enabling Account Abstraction)** and indexed by **Apibara**. What we achieved was a secure and instant **USDT/USDC conversion to RWF** directly into **MTN Mobile Money** accounts via a **WhatsApp Bot** interface.
技术栈
融资状态
Open to funding.