Every fill in the log carries a latency written as two numbers — 4ms + 71ms — because it is two different things added together, and adding them hid which one was which.
The first number
Tradeus. From the moment your alert reaches our webhook until the order leaves for your broker: reading the payload, checking the passphrase, finding the strategy, sizing the position, running your risk rules. This is the part we can make smaller, and it is usually single digits.
The second number
Your broker. From the order leaving until the broker confirms it and gives back an order id. Most of this is distance — light in fibre covers about 100 km per millisecond of round trip, so a broker on another continent costs over a hundred milliseconds before anyone has done any work.
Why not one number
The single figure was read as our speed and never was. Split, a slow trade tells you where to look: a large first number is ours to answer for, a large second one is the wire and the broker.
A dash in the second place (4ms + —) means the broker never told us how long it took. A single number on its own is a fill from before this split existed.
Occasionally a row says attempts as well. That means the first order was refused and Tradeus asked again. The wait between the tries belongs to neither half, so it is named rather than folded into one of them.
What single-digit end-to-end would take
Nobody reaches a broker in ten milliseconds over the public internet unless the server sits in the same building as the broker's matching engine. Anyone advertising that number is quoting their own processing — the first of these two — without the second beside it.