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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 WebSocket block streaming, PostgreSQL persistence, TTL caching, Swagger API docs, and a React frontend deployed on Vercel.

Full-Stack EngineerGluwa / 2022–2023
GitHub Live Demo

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 system with a NestJS + Prisma backend, real-time block streaming, a PostgreSQL persistence layer, a caching system with TTL eviction, and a React frontend.

Live demo: https://substrate-explorer-frontend.vercel.app/

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