Writing
Notes from building and running production-grade Excel trading infrastructure on the Interactive Brokers TWS API — including The Hardening Journey, a series on the problems that took half a year and seventeen thousand lines of C# to solve properly.
Essays
Why Excel
The case for the spreadsheet as production trading infrastructure. The 2005 objections are gone; the bottleneck moved from "can the grid hold the data" to "can you keep it correct under load" — and that is where the real engineering lives.
Beyond Market Data
Building a production Excel trading dashboard on the IBKR TWS API — and why the part that looks easy isn't. IBKR's RTD sample leaves the callbacks for accounts, positions, and orders as empty stubs; filling them in is a cliff. The setup for the series, and the one rule it turns on: fail loud.
Keeping the Dashboard Current
When the connection to the IBKR TWS API drops — and it will — the dashboard has to put itself back together. A reconnection story in four acts: four bugs nested one inside the next, the undocumented connection states behind them, and the state-machine rebuild that made a class of races unreachable.
When Excel Stops Listening
Excel enforces an RTD contract it never wrote down — and when a server breaks it, the penalty is silence. The COM reentrancy trap, the broken-trust freeze, the dedup fan-out, and keeping proof, in band, that the host is still hearing you.
The Last Click
Staging orders from a spreadsheet — an apparent anti-pattern, given that RTD streams data into Excel — and the one discipline that keeps it safe: minimize the number of clicks; never zero. The series closer.
Guides
Practical references for getting Interactive Brokers data into Excel.
IBKR in Excel: the account, positions & orders gap
IBKR's free Excel RTD sample streams market data only — accounts, positions, and order callbacks are empty. What the free tools cover, what they don't, and how desks fill the gap.
IBKR RTD not working? Fixing #N/A and stuck cells
Why =RTD() cells show #N/A or stop updating — ProgID and registration, TWS API not enabled, port mismatch, 32/64-bit, the throttle interval, the 50-messages/second limit, market-data lines, and the stale-TWS-API version floor. A fix for each.
RTD vs DDE vs ActiveX for Excel + IBKR
The four ways to wire Interactive Brokers into Excel — RTD, DDE, ActiveX, and manual export — with honest trade-offs on coverage, robustness, streaming, and setup.
Python in Excel vs RTD for live trading data
Microsoft's Python in Excel runs in the cloud and recalculates on demand — why that execution model can't continuously stream live local data like TWS, and how RTD's local push model differs.