Payment Kita — Product Description

Payment Kita is a hybrid payment gateway and cross-chain payment infrastructure that enables merchants to accept and process payments across multiple blockchains, tokens, and fiat systems within a single unified platform.

In simple terms:

Payment Kita is a bridge between users, merchants, blockchain networks, and traditional financial systems.

1. Tech Stack (System Architecture)

Backend Core

1. Golang (Gin) or NestJS
   
2. High-performance API services with strong concurrency handling for transaction processing
3. PostgreSQL
   
4. Stores transaction data, merchant information, and settlement records
5. Redis
   
6. Used for caching, session handling, and idempotency control
7. RabbitMQ or Kafka
   
8. Event-driven messaging for payment updates, settlement processes, and webhook delivery

Blockchain Layer

1. EVM Chains (Ethereum, BSC, Polygon, etc.)
2. Solana (SVM)

Smart contract components:

1. Payment contracts
2. Escrow and settlement logic
3. On-chain event listeners for transaction validation

Interoperability Layer

1. LayerZero, Chainlink CCIP, or Hyperbridge
   
2. Enables cross-chain messaging and asset transfer
3. DEX Integration
4. EVM: Uniswap v3/v4
5. Solana: Jupiter or Raydium

Main responsibilities:

1. Token swapping
2. Cross-chain routing
3. Liquidity sourcing

Security Layer

1. JWE or AES encryption
   
2. Used for securing QR payloads and payment data
3. Wallet signature verification
4. Access control and audit logging

Frontend and Integration

1. Web dashboard (Next.js or Svelte)
2. Mobile applications (Flutter)

APIs are provided for:

1. Merchants
2. Partners
3. Wallet integrations

External Integrations

1. Fiat payment rails such as QRIS, Virtual Accounts, and e-wallets
2. Blockchain RPC providers
3. Notification systems including webhooks, email, and messaging services
4. 
   

2. System Flow (End-to-End)

Step 1: Create Payment

The merchant creates a payment request:

POST /create-payment

The system returns:

1. payment_id
2. amount
3. destination_chain
4. destination_token
5. payment_url
6. QR code or deep link

Step 2: User Payment

The user completes payment using:

1. A crypto wallet
2. Cross-chain payment
3. Any supported token

Step 3: Routing Engine (Core Logic)

If the source chain or token differs from the destination:

1. The system detects the incoming asset
2. Performs token swap via DEX
3. Bridges the asset to the destination chain

Step 4: On-chain Verification

Blockchain listeners monitor transactions and validate:

1. Payment amount
2. Sender wallet
3. Target chain

Step 5: Settlement

Funds are credited to:

1. Merchant wallet or internal balance system

Payment status is updated:

1. SUCCESS or FAILED

Step 6: Notification

1. Webhook is sent to the merchant backend
2. Dashboard updates in real time

3. Main Functions

Multi-Payment Acceptance

Supports:

1. Crypto (BTC, EVM chains, Solana)
2. Stablecoins
3. Fiat payments (QRIS, Virtual Accounts, etc.)

This allows merchants to serve a wider range of customers.

Cross-Chain Payment

Enables users to pay from one chain while the merchant receives funds on another chain.

Example:

USDT on BSC can be converted and settled as IDRX on Polygon.

Automatic Token Conversion

1. Integrated with decentralized exchanges
2. Supports slippage control

Users can pay with any supported token without manual conversion.

Payment Links and QR Codes

1. Generates encrypted QR codes
2. Provides deep links for wallet interaction

This creates a seamless payment experience similar to traditional payment gateways, but enhanced with Web3 capabilities.

Merchant Dashboard

Provides:

1. Transaction monitoring
2. Settlement tracking
3. Analytical insights

Webhooks and API Integration

1. Real-time transaction updates
2. Easy integration into merchant systems

Balance and Settlement System

1. Merchant balance tracking
2. Withdrawal management
3. Refund handling

Secure Payment Payload

QR codes and deep links contain:

1. payment_id
2. merchant_id
3. amount
4. destination_chain
5. destination_token
6. destination_wallet

All data is encrypted for security.

Cross-Border Payment (Future Vision)

1. Enables international transactions
2. Automatic conversion between currencies and tokens
3. Designed to improve cross-border financial flow efficiency

Positioning

Payment Kita is more than a traditional payment gateway.

It is a hybrid payment infrastructure that combines:

1. Traditional fintech payment systems
2. Blockchain networks (EVM and Solana)
3. Cross-chain interoperability
4. Decentralized liquidity through DEX integration

Simple Analogy

If:

1. Stripe or Midtrans represents fiat payment gateways
2. MetaMask represents crypto wallets

Then:

Payment Kita represents a unified system that combines payment gateway functionality, decentralized exchange capabilities, and cross-chain infrastructure into one platform.



Key Strengths

1. Chain-agnostic architecture
2. Token-agnostic payment support
3. Integration of Web2 and Web3 payment systems
4. Designed as a universal payment layer for modern digital transactions