07 · Live price webpage (client-side, no backend)

A single index.html that shows live Chainlink prices for 11 Stock Tokens, read entirely in the browser via JSON-RPC eth_call against the public Robinhood Chain RPC. No backend, no build step, no API key, no dependencies — which is exactly why it runs on GitHub Pages and is embedded, running, in this repo's docs gallery.

What it proves: read-only chain calls work straight from a static page. Prices tick every 15s with up/down flash, per-card answer age, and designed loading / error / empty states.

Prerequisites

• A browser. Node ≥ 20 only if you want the convenience npm start server.

Run

npm start                 # → http://localhost:8007  (zero-dep node:http server)
# — or just —
open index.html           # the page is fully self-contained

What you see

A responsive grid of price cards:

(Live values captured from the RPC while building — all 11 feeds returned real prices: AAPL 315.50, TSLA 407.82, NVDA 210.19, MSFT 384.69, AMZN 245.57, GOOGL 356.72, META 670.67, AMD 558.21, COIN 159.43, PLTR 126.56, SPCX 145.72.)

The status pill reads live · chain 4663 · 11/11 feeds · every 15s when healthy, and flips to a red RPC unreachable — retrying state if every read fails. The 15s answer ages reflect the 24/5 feed schedule (weekend reads are a day or two old — expected, not a bug).

How it works (the whole trick)

latestRoundData() has selector 0xfeaf968c and returns five 32-byte words; the price is word #1 (int256, 8 decimals) and the timestamp is word #3. The page hard-codes the 11 feed addresses from the hoodchain registry and decodes the answer with three lines of BigInt math — no ABI library needed.

Built by nirholas · three.ws