Altscan explorers

Altscan

The open-source, multi-chain block explorer platform.

One codebase powers independent explorers for BNB Chain and Ethereum today — and is built to add more chains over time.

Next.js 15, Drizzle ORM, and ethers.js. Maintained by Measurable Data Token (MDT) .

altscan.io | bnbscan.com | ethscan.io | Changelog

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What is this?

Altscan is an open-source, multi-chain block explorer platform. One codebase powers two independent explorers today — BNBScan (bnbscan.com, BNB Chain) and EthScan (ethscan.io, Ethereum) — and is designed to extend to more chains over time. They are fully independent from BscScan, Etherscan, Binance, or the Ethereum Foundation, providing a clean, fast interface for exploring blocks, transactions, addresses, tokens, and on-chain activity.

A single CHAIN environment variable selects which chain a deployment serves — same frontend, same indexer, same schema.

Screenshots

Captured from production on 12 October 2026, with the sponsored slots switched off.

Features

Exploration

• Block tape — the latest blocks drawn as a live strip (width = transactions, fill = gas used), on the homepage and through the block, transaction, address and analytics pages
• Blocks — the latest blocks with validator, gas, and transaction counts; each block page lists its transactions
• Transactions — a one-line summary of what happened, the fee breakdown, logs, and token and NFT transfers; internal transactions when a trace endpoint is configured (off by default)
• Addresses — balance and tracked-token holdings, transaction history drawn as a ledger, token transfers, and NFTs
• Tokens — ERC-20 / BEP-20 pages with market data, holders, and transfers; lookalike (homoglyph) tokens are labelled
• Search — addresses, transaction hashes, block numbers, and token names or symbols

Analytics

• DEX Trades — Uniswap-V2-style swaps (PancakeSwap V2 on BNB Chain, Uniswap V2 on Ethereum); V3-style pools are not indexed
• Whale Tracker — the largest native, wrapped and stablecoin transfers in the last hour, the last day, or the whole retained window
• Gas Tracker — slow, standard and fast prices from the percentiles of recent blocks
• Network Charts — transaction count, blocks produced, and (on Ethereum) average base fee; hourly until the index holds three full days
• Validators (BNB Chain) — the validator set with voting power, commission, and blocks produced in the last 24 hours

Developer Tools

• REST API — a v1 query API, optional API keys minted by signing a message with your wallet, and webhooks
• CSV Export — the latest 1,000 locally indexed transactions for an address
• Contract status — shows whether a contract is verified on Sourcify; verify new source at sourcify.dev

Also

• Dark mode that follows the system setting, and layouts built for phones
• Watchlist — save addresses in your browser (no account, nothing leaves the device)
• Network switcher — links to the sister explorer on the other chain
• Status page — status.altscan.io tracks uptime, block lag, and response time for the hosted explorers

Architecture

altscan/

├── apps/ │ ├── explorer/ Unified Next.js 15 frontend + API routes │ │ CHAIN=bnb → bnbscan.com │ │ CHAIN=eth → ethscan.io │ ├── indexer/ Unified block indexer (direct polling loop) │ │ CHAIN=bnb → indexes BNB Chain │ │ CHAIN=eth → indexes Ethereum │ ├── status/ Hono status page for the hosted explorers │ │ Polls /api/health on bnbscan.com and ethscan.io │ ├── altscan-site/ altscan.io umbrella site (Astro on Cloudflare Workers) │ └── admin/ Operator console behind Cloudflare Access (Astro on Cloudflare Workers) ├── packages/ │ ├── chain-config/ getChainConfig() — chain-specific config │ ├── db/ Drizzle ORM schema + Postgres client │ ├── explorer-core/ Shared utils (rate limiting, formatting, Redis cache) │ ├── providers/ Third-party data adapters (Moralis) and their spend budgets │ ├── settings-schema/ Runtime settings shared by the explorer and the admin console │ └── types/ Shared TypeScript types ├── render.yaml Render blueprint for the hosted explorers ├── docker-compose.yml Self-host stack: Postgres, Redis, indexer, explorer ├── turbo.json Turborepo pipeline config └── pnpm-workspace.yaml

Tech Stack

How It Works

1. Indexer connects to a chain's JSON-RPC endpoint, polls for new blocks, and writes block/transaction/token data to Postgres via Drizzle ORM.
2. Explorer serves the Next.js frontend with ISR (Incremental Static Regeneration) — each page revalidates on its own schedule, from 45 seconds to five minutes, for fresh data without server pressure. Pages that depend on the request, such as search, render per request.
3. Chain Config package centralizes all chain-specific differences (block time, currency, theme colors, RPC URLs, feature flags) so the same code runs both chains.
4. Status Page independently monitors the two hosted explorers by polling their /api/health endpoints every 30 seconds, tracking uptime, block lag, and response time over 24 hours and 30 days. Its targets are fixed in apps/status/src/server.ts, and it is not part of the Docker stack or the Render blueprint.

Getting Started

Run your own explorer (Docker)

git clone https://github.com/heathermhuang/altscan.git

cd altscan cp .env.docker.example .env docker compose up -d

Open http://localhost:3000. That's Postgres, Redis, the indexer, and the explorer — no configuration required to start, and the indexer creates its own schema on first boot. Set CHAIN=eth in .env and re-run with --build for Ethereum.

Full guide, including Render deployment, retention tuning, and limitations: [docs/SELF_HOSTING.md](docs/SELF_HOSTING.md).

Develop locally (without Docker)

Prerequisites

• Node.js 22 — what CI and the Docker images run
• pnpm 10 — pinned in package.json; corepack enable picks up the exact version
• PostgreSQL 16
• Redis 7 — optional: without REDIS_URL, rate limits and caches fall back to per-process memory

Installation

# Clone the repo

git clone https://github.com/heathermhuang/altscan.git cd altscan

Install dependencies

pnpm install

Start Postgres from the Docker stack (localhost:5432; user, password and database all "altscan")

docker compose up -d postgres

Set up the explorer environment (defaults match the local Docker Postgres)

cp apps/explorer/.env.example apps/explorer/.env.local

Start the BNB explorer

CHAIN=bnb NEXT_PUBLIC_CHAIN=bnb pnpm --filter @altscan/explorer dev

The BNB explorer will be available at http://localhost:3000. The indexer creates the database schema on its first boot, so run it once (below) before expecting data; the explorer alone, against an empty database, has no tables to read. pnpm dev starts every app at once through Turborepo: the explorer, the indexer, the status page, and both Astro sites.

Running a specific chain

# BNB Chain explorer only

CHAIN=bnb NEXT_PUBLIC_CHAIN=bnb pnpm --filter @altscan/explorer dev

Ethereum explorer only

CHAIN=eth NEXT_PUBLIC_CHAIN=eth pnpm --filter @altscan/explorer dev -p 3001

BNB indexer only — build the packages it imports first (see below)

pnpm --filter @altscan/db build && pnpm --filter @altscan/chain-config build && pnpm --filter @altscan/explorer-core build && pnpm --filter @altscan/providers build CHAIN=bnb pnpm --filter @altscan/indexer dev

Status page only (monitors the hosted sites)

pnpm --filter @altscan/status dev

CHAIN drives the server; NEXT_PUBLIC_CHAIN is inlined into the client bundle, so set both to the same chain. The indexer reads its settings from the environment or from apps/indexer/.env: at least DATABASE_URL (or ETH_DATABASE_URL), the chain's RPC URL, and a START_BLOCK near the chain head — its built-in start is millions of blocks back.

The explorer compiles the workspace packages from source, but the indexer loads their built dist/ output, which is not committed — build them once after cloning and again after changing them.

Environment Variables

These are the variables a deployment needs. apps/explorer/.env.example adds the optional provider caps, and docs/SELF_HOSTING.md covers the indexer's retention and disk settings.

| CHAIN | Yes | bnb or eth — selects which