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HASH: 0x0022...2025.11 - Present

BEATOZ CPG (Core) - Crypto Payment Gateway

Payment Gateway

System Description

Solo-built crypto payment gateway monorepo with a NestJS API, chain-specific monitoring workers, HMAC-signed webhooks, and admin/merchant dashboards.

Technologies

TypeScriptNestJSPostgreSQLRedisBullMQNext.jsTailwindCSSDockerAWS EC2PrometheusGrafana
BEATOZ CPG (Core) - Crypto Payment Gateway
ROLE: SOLO_DEVELOPERDOMAIN: BLOCKCHAIN
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PROBLEMThe Challenge

Had to keep payment state consistent across heterogeneous networks while supporting both API-driven flows and direct wallet transfer detection. Also needed merchant/store onboarding and configuration (for store pages), integrated payment UX (widget/session/custom payments), custody wallet operations, settlement processing, and webhook delivery tracking.

✓

SOLVEDThe Solution

Implemented merchant/store APIs including a public merchant list for store pages and a Developer Site registration flow (auto-approve), backed by SSOT API credentials. Built a unified payment orchestrator (Strategy/Adapter) with SSOT QR persistence and conditional chain scanning, plus chain-specific workers/processors. Implemented payment products APIs (integrated payments, widgets, custom payments) with session/status endpoints and supporting services (exchange rate/gas fee calculation). Added custody wallet management and an HMAC-signed webhook delivery system with retry + persistence.

SYSTEM_COMPONENTS

Backend API

Payment Engine & Settlement

Tech Stack

NestJSTypeORMPostgreSQLBullMQ

Highlights

  • →Unified payment orchestrator (Strategy/Adapter)
  • →Chain-specific workers & processors
  • →Settlement queues & controllers

Dashboards

Admin & Merchant UI

Tech Stack

Next.jsTailwindCSSshadcn-ui

Highlights

  • →Admin dashboard
  • →Merchant dashboard
  • →Operational tooling

Payment Products

Widget / Session / Custom Payment

Tech Stack

NestJSCQRSDTO/VO

Highlights

  • →Integrated payment sessions
  • →Payment widget config
  • →Custom payment flows
Technical Deep Dive

Overview

  • ▶Solo-built crypto payment gateway monorepo: API + monitoring workers + webhooks + operations dashboards.

Key Components

  • ▶Merchant/store onboarding (public merchant list + Developer Site store registration)
  • ▶Strategy/Adapter payment orchestration per chain/payment type
  • ▶Integrated payment products (widget/session/custom payment) and configuration endpoints
  • ▶Custody wallet management and provider-based key signing
  • ▶Queue-separated monitoring workers for transaction detection/confirmation
  • ▶HMAC-signed webhooks with retry policies and delivery tracking
  • ▶Settlement and operational dashboards (Admin/Merchant)