How I built a Binance signal confluence panel for a Polymarket whale tracker

#javascript #web #cryptocurrency #buildinpublic

I run WhaleTrack (whaletrack.app) — a site that tracks what the biggest Polymarket wallets are betting on in real time.

This week I shipped a market intelligence panel to the crypto page that combines Polymarket whale bets with Binance futures data. Here's how it works technically.

The idea:-

Coinglass already shows L/S ratios. Whalemap shows whale trades. What nobody shows is: does Binance top trader positioning agree with what the Polymarket whales are betting? That confluence is the signal.

The 3 Binance public endpoints I used (no auth needed):

/futures/data/globalLongShortAccountRatio?symbol=BTCUSDT&period=5m
/futures/data/topLongShortAccountRatio?symbol=BTCUSDT&period=5m
/fapi/v1/premiumIndex?symbol=BTCUSDT

How I made it resilient:

Each coin fetches independently via Promise.all — one failure doesn't kill the whole panel
AbortSignal.timeout(8000) on every fetch so a slow API never hangs the UI
Stale cache fallback — if a fetch fails, shows last known data with a "cached" label instead of going blank
Price ticker has dual-source: CoinGecko primary, Binance spot API fallback

Signal logic:

2+ bullish indicators → BULLISH, 2+ bearish → BEARISH, else NEUTRAL

Live at whaletrack.app/crypto — would love technical feedback on the approach.