ln.fyi

An editorial atlas of the Bitcoin Lightning Network.

A live, open dashboard tracking capacity, nodes, channels and onchain activity across Lightning. No accounts, no API keys. Anonymous page-view counts via Vercel Analytics.

Live at ln.fyi.

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What's inside

• Network overview — total capacity, node/channel counts, 30-day deltas, multi-year history charts.
• Node directory — top nodes by capacity and connectivity, searchable.
• Node profiles — per-node capacity/channel history, server metadata (AS, geo, Tor/clearnet sockets), and a public onchain transactions feed reconstructed from channel opens and closes.
• Report cards — a public 0–100 grade (A+ to F) from the daily ranking snapshot: capacity, channels, connectivity rank, and age. Shown on the node page, its share image, and a top-20 list at /grades.

Stack

• Next.js 16 (App Router, RSC, route-level revalidate)
• React 19, TypeScript 5
• Tailwind CSS 4
• IBM Plex Sans / Sans Condensed / Mono
• Data: mempool.space Lightning REST API

Lightning data comes from the emzy.de mempool mirror first. The public mempool.space instance still answers, but its Lightning snapshots lag by days, so it is only used when emzy stalls or returns 429. Set MEMPOOL_PROVIDERS to change the order.

Running locally

npm install
npm run dev

Open http://localhost:3000.

Scripts

Command	Action
npm run dev	Start the dev server
npm run build	Production build
npm run start	Serve the production build

Environment

Variable	Default	Purpose
MEMPOOL_PROVIDERS	emzy, then mempool.space	Comma-separated Lightning API bases, tried in order
NEXT_PUBLIC_MEMPOOL_BASE	unset	Legacy single base. A public instance stays primary and the other public instance is kept as backup. A custom URL is used alone.
GOOGLE_SITE_VERIFICATION	unset	Google Search Console token. Emitted as google-site-verification only when set.
BING_SITE_VERIFICATION	unset	Bing Webmaster token. Emitted as msvalidate.01 only when set.

Project layout

src/
  app/
    page.tsx              # Network overview (/)
    nodes/                # Node directory + profiles
    about/                # About page
    layout.tsx            # Root shell, fonts, metadata
  components/             # Panel, chart, stat, shell, hero-number, live-tick
  lib/
    api.ts                # mempool Lightning API client + formatters

All data fetches are server-side with Next.js cache revalidation. The network overview stays on a short window (about 2–10 minutes). Node profile pages and their Open Graph images revalidate once a day when the primary directory answers. Each upstream call has a 4 second budget and fails over to the next provider after about 2 seconds, so a hung host cannot hold the render. The node document is loaded once per request and shared with generateMetadata. The top 20 nodes by capacity are prerendered.

Node grades read one daily snapshot of the primary ranking lists (capacity, connectivity, age) and the network median. That snapshot does not fail over to mempool.space, whose Lightning data lags, and it does not add a per-node fetch. A fee sample from channels the profile already loaded is shown beside the grade and is not part of the number.

A profile is cached as missing only when the pubkey is impossible, the upstream API returns 404, or mempool's node route answers 500 {"error":"Failed to get node"} and node search on that host agrees the key is absent. If the primary is down and a previous good profile exists, that page stays up. A pubkey that has never been cached renders a short-lived unavailable page (about a minute) instead of a 500. Backup-provider data is kept for about 10 minutes so the primary is tried again soon. There is no client-side polling.

Contributing

This is a personal project, but issues and PRs are welcome — especially for data-quality fixes, accessibility, and new editorial views of the network.

License

Public domain.