"I built the onboarding system that let 12 institutional clients connect to ACY's FIX gateway.
Then I asked: what should the terminal on top of that gateway actually look like?"
— Ed Chen · Senior Product Designer · 4 years at ACY Securities
67%
Support ticket reduction
3×
Faster FIX integration
12+
Institutional clients
16
Protocol-traced decisions
Auto-launching in 5s
WATCHLIST22
RSI (14)
SPX
NDX
GOOG
NVDA
ExchangeOrdersSizeBid
—
—
AskSizeOrdersExchange
■ Bids (cumulative)■ Asks (cumulative)
$0.00
Orders are simulated. Not financial advice. Demo only.
TimePriceSizeSideExchange
POSITIONS
InstrumentQtyEntryCurrentP&LP&L%VAR(1D)
CORRELATION MATRIX (30D)
SenderCompIDTRADEX_PRO_001
TargetCompIDACY_FIX_GW
Hostfix.acyconnect.com
Port4001
FIX VersionFIX.4.4
HeartBtInt30s
SESSION STATE MACHINE
TCP
Connected
35=A
Logon
Active
Session OK
35=0
Heartbeat
loop [ 30s ]
30
NEXT HEARTBEAT
35=0 in 30s
HeartBtInt=30 per FIX 4.4 §4.3
Uptime
04:23:17
Msg Sent
1,847
Msg Recv
2,341
Rejects
3
Fill Rate
98.4%
Latency
0.4ms
SIMULATE SCENARIO
TAG 39 ORDSTATUS LIFECYCLE
39=A · PendingAccepted, awaiting liquidity
39=1 · PartFillCumQty < OrderQty
39=2 · FilledLeavesQty = 0
39=4 · CancelledCancelRequest ack
39=8 · Rejected35=3 BusinessReject
TAG 150/39 CONFLICT (ExecType vs OrdStatus)
Tag 150=1 (Trade) + Tag 39=1 (PartFill) → Triggers CumQty update, order stays active
Tag 150=E (PendingReplace) + Tag 39=1 → Modification in-flight, old order not dead
⚠ Anti-pattern: 500+ symbol MarketDataRequest overloads gateway — use single-symbol per session
FIX MESSAGE STREAMLIVE
TIMESTAMPDIR35=MSG TYPEPAYLOAD
IV Rank: --P/C Ratio: --Max Pain: --
BIDASKIV%OIVolSTRIKEVolOIIV%BID/ASK
No active algorithms Submit an order ≥1,000 shares to auto-activate TWAP · GTC orders route to VWAP
OPEN ORDERS
ORDER HISTORY
ORDER BOOK · L3—
EXCHORDSIZEASK
——
EXCHORDSIZEBID
BID TOTAL—ASK TOTAL—
Ready · SPX · NYSE|Keys: 1-5 Instruments · M Multi · Tab Tabs · Esc CloseLatency: 0.4ms · FPS: 60
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TradeX Institutional Terminal
Portfolio Demo · Ed Chen · Senior Product Designer
What this demonstrates
Every design decision in this terminal is derived from a real protocol constraint — not from Bloomberg screenshots. The FIX 4.4 session monitor, Tag 39 OrdStatus lifecycle, partial fill states, and L3 order book scope are all direct translations of FIX Protocol rules into UI decisions, documented through production work on ACY Connect (12+ institutional clients, 67% support ticket reduction).
FIX 4.4 Protocol Layer
Live FIX session state machine (TCP → Logon 35=A → Active → Heartbeat 35=0 loop). Real-time message stream with tag parsing. Tag 39 OrdStatus badges (A Pending → 1 PartFill → 2 Filled). NewOrderSingle (35=D) FIX message preview in Order Entry. Order execution triggers live FIX message flow. HeartBtInt=30s countdown ring.
Design Mode (🎨 button)
Toggle Design Mode to reveal annotation overlays showing exactly why each UI element was designed the way it was — every annotation maps to a FIX protocol constraint or institutional UX decision. This is the designer's layer: Protocol → Design decisions made visible.
Technology
Pure HTML/CSS/JS — no frameworks. LightweightCharts v4.2.0. ResizeManager (col-resize + row-resize drag). FloatingPanel (grab drag + SE-corner resize). FIX 4.4 message simulation engine. Canvas API for Depth chart. All data is simulated with realistic random walks seeded from real market structure.