How these systems actually behave.

One long read and two shorter pieces, each following a single failure or constraint far enough down that the design decisions around it stop looking arbitrary.

• LONG READ
  9 MIN

  A timeout is not a fill

  Every order-management system has to decide what to do when the broker does not answer. Most of them decide it in one line, early, before anyone has thought about it — and that line is where the money leaks out. This is what the problem actually looks like once you follow it down.
• NOTE
  3 MIN

  A fill cannot use the signal bar

  Point-in-time is a contract, not a slogan. Two things kill most backtests before the idea is even wrong: seeing data you could not have seen, and not paying what you would have paid.
• NOTE
  3 MIN

  Not every hypothesis graduates

  Ideation to live capital is a sequence of kill-gates, and the gates are the product. An engine that never rejects an idea is not measuring anything.