ArbScan

Read-only crypto arbitrage scanner for Binance, Bybit, OKX, Bitget, MEXC, Gate, KuCoin, HTX. No API keys, no trading — public market data only.

What it finds

• Triangular (same exchange): USDT → A → B → USDT, after 3 taker fees, with top-of-book size.
• Exchange ↔ exchange: buy where the ask is lowest, sell where the bid is highest (taker fees on both sides; withdrawal fees not included).
• Honest numbers: every "You keep" figure is after fees, spread and withdrawal fee, only on the size that fits; funding uses the lower of today's rate and the 3-day average (api/history.js).
• Futures gap (api/perps.js): perp vs perp on two exchanges — long the cheap one, short the expensive one, no transfer.
• Real order book (api/depth.js): top cross-exchange rows are walked through 20–100 book levels with your amount; best size shown.
• Instant mode: cross-exchange with coin + USDT pre-held on both exchanges (no transfer, no withdrawal fee).
• Paper trades: track a funding trade in the browser and see the funding actually paid since you started, minus costs.
• Funding rate:
  • cash & carry on one exchange (long spot + short perpetual),
  • cross-exchange funding spread (short the high-funding perp, long the low one),
  • fees, break-even days and net result for a chosen holding period.
• Fees tab: editable spot/futures taker fees per exchange (stored in your browser).
• Junk filter: markets below a minimum 24h USD volume (default $250k, quote volume converted to USD on the same exchange) and leveraged tokens (BTC3L, ETHUP, …) are removed; suspicious rows (>5% / size < $10) hidden by default.
• Investment calculator: enter an amount (default $100) to see the dollar profit per route, what you get back, and whether the best price can absorb the whole amount.

Structure

• lib/exchanges.js — exchange adapters (public REST endpoints), normalised to one format.
• api/spot.js?ex=binance — top-of-book bid/ask (+ 24h quote volume) for all active spot markets.
• api/funding.js?ex=binance — USDT perpetual funding rates.
• api/health.js — which exchanges respond from the server region.
• arb.js — arbitrage maths (shared by browser and tests). npm test runs test/arb.test.mjs.
• index.html, app.js, style.css — dashboard.

Serverless functions run in fra1 (Frankfurt) because several exchanges block US IPs.

Caveats

Opportunities shown are snapshots of the best bid/ask. Real fills depend on order-book depth, latency, deposit/withdrawal status, networks and fee tier. This is not financial advice.

Paper bot (no real money)

scripts/paper-bot.mjs runs every hour on GitHub Actions (.github/workflows/paper-bot.yml) and keeps two $100 paper wallets: funding carry and instant buy-and-sell. State and REPORT.md live on the paper-data branch; each run's report is also in the Actions run summary. Data comes from this project's Vercel API (Frankfurt).