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🔍 Substrate Blockchain Explorer

🔍 Full-stack blockchain explorer for a Substrate network — built from scratch, not a fork. NestJS + Prisma backend with real-time Socket.io block streaming, PostgreSQL, TTL caching, Swagger docs, and React frontend on Vercel.

Full-Stack EngineerGluwa / 2022–2023
GitHub

Stack

NestJSTypeScriptPrismaPostgreSQLPolkadot.js APISocket.ioReactTailwind CSSDockerRailwayVercel

Substrate Blockchain Explorer

🔭 Overview

A full-stack blockchain explorer built from scratch for a Substrate-based network in the Polkadot ecosystem. Not a fork of an existing explorer — a purpose-built NestJS + Prisma backend with real-time block streaming, a PostgreSQL persistence layer, a caching system with TTL eviction, and a React frontend.

🛠️ What I Built

⚙️ Backend (NestJS + Polkadot.js)

  • 📡 Real-time block streaming: WebSocket subscription to Substrate node via Polkadot.js API, streaming new blocks and events via Socket.io to connected frontend clients
  • 💾 PostgreSQL persistence: Prisma ORM schema for blocks, extrinsics, events, and account data
  • ⚡ Caching layer: Redis-backed caching with TTL eviction for frequently queried endpoints (latest blocks, account balances, transaction counts)
  • 📚 Swagger/OpenAPI documentation: Full API documentation for all explorer endpoints
  • 🌐 Multi-network support: testnet, devnet, and mainnet configuration via environment variables

🎨 Frontend (React + Tailwind CSS)

  • 📡 Real-time block list with WebSocket-powered live updates
  • 📋 Extrinsic detail pages with decoded call data
  • 👤 Account pages with balance, nonce, and transaction history
  • 📜 Event log viewer with filtering by pallet and event type
  • 🚀 Deployed on Vercel with Railway backend hosting

🏗️ Architecture Patterns

  • ⚡ Event-driven: on-chain events trigger persistence and cache invalidation
  • 🧩 Modular NestJS service structure (block processor, event indexer, WebSocket gateway, REST API)
  • 🐳 Docker Compose for local development with PostgreSQL and Redis

⭐ Key Highlights

  • 🏗️ Built from first principles — no existing explorer fork
  • 📡 Real-time WebSocket block streaming to multiple simultaneous clients
  • ⚡ Production-grade caching design with explicit TTL management
  • 📚 Full Swagger documentation for all API surfaces
  • 🚀 Deployed and running against a live Substrate network