📈 Tape Lab
Practise reading the tape on replayed and recorded market data — with a simulated order
ticket, an order-flow lab, and a score that grades your reads, not your P&L.
No signup. No broker. No live feed. Everything runs in your browser.
Quick start · What's inside · Data · Legal · Corrections
⚠️ Read this first
Tape Lab is a training tool, not a trading system. Fills are simulated with a
documented candle-based model. Nothing here is a broker fill. There is no live
market data and no broker connection — the app cannot place a real order, and it
never asks for an account, a key, or a password.
Most people who day trade lose money. Nothing in this repository is financial advice,
a signal service, or a track record.
Screenshots
| Flow Lab — order flow & DOM | Score — graded replay |
|---|
| |
| Journal — tagged trade notes | Academy — the original course |
| |
What's inside
Seven pages, all of them practising the same skill from a different angle.
| Page | What you do |
|---|
| 🕯️ | Terminal | Step through real OHLC bars one candle at a time at 0.5x–100x. The future is never revealed to the UI. Place market, limit and stop orders; set stop-loss and take-profit; flatten and reverse. |
| 🙈 | Blind Mode | Hide the chart and predict the next move. Your calls are recorded and scored — so you find out whether you can actually read it, or you just recognise the shape afterwards. |
| 🌊 | Flow Lab | Watch the tape: delta, CVD, volume-at-price, spread, microprice, aggression, and a top-10 DOM with imbalance, stacking, pulling and sweeps. Five blind scenarios (Spring, Upthrust, Absorption, Initiative Break, Responsive Fade) with the answer hidden behind "Reveal what it was". |
| 🎯 | Scenarios | Tagged historical setups you can jump back to and replay until the read is automatic. |
| 📥 | Data | Import your own 5-minute NQ/ES CSVs. Parsed in the browser, stored in IndexedDB, never uploaded anywhere. |
| 📓 | Journal | Every simulated trade with your notes, tags and screenshots. Exports to CSV. |
| 🏅 | Score | A multi-factor replay score — process, risk and read quality — not just whether the trade made money. |
Also in there: VWAP, custom-length EMAs (any period, each with its own colour), opening
range, full performance statistics, keyboard-driven stepping, and a clear
SIMULATED TRADING · HISTORICAL REPLAY badge on every screen so you never forget what
you are looking at.
Quick start
You need Bun. Then:
bun install
bun run dev
Opening http://localhost:5173 gives you the landing page; the terminal itself is at
/app.html. A clearly-labelled synthetic demo dataset is seeded automatically, so the
terminal works the moment it loads — you do not need to own any market data to try it.
bun run dev # dev server (Vite)
bun run build # production build -> dist/
bun run preview # serve the built output
bun run typecheck # tsc -b --noEmit
bun test tests # unit tests
bunx playwright test # browser tests (chromium)
bun scripts/verify.ts # core data / replay / execution checks
What data is actually in it
This is the part most trading apps are vague about. Here it is plainly.
| Source | What it really is | Where |
|---|
| Synthetic demo dataset | A seeded random walk generated in your browser. Not recorded history. | Terminal (NQ/ES sessions), seeded on first load |
| Synthetic training feed | A deterministic synthetic event feed — seeded trades, Level-2 snapshots, book resets. Same seed ⇒ identical events. Labelled Synthetic Training Data everywhere it appears. | Flow Lab |
| Binance Spot BTCUSDT | A genuine recorded venue capture. | Flow Lab |
| Binance Vision historical aggTrades | A genuine recorded venue capture. | Flow Lab |
| Your own CSVs | Time, Open, High, Low, Close, Volume. Parsed in the browser, stored in IndexedDB. Never uploaded. | Data page |
The OHLCV datasets contain no Time & Sales, bid/ask or Level-2 information. Flow Lab's
order-flow view is a separate engine on separate data.
The bundled recordings are included for individual educational use only and are not
licensed for redistribution. See LICENSE and THIRD-PARTY-NOTICES.md.
This is the beginning of the README. Read the rest at the original. Read the full README ↗
