DROP ALERT NOTES
What recheck=N does on the prematch drop stream
recheck=N holds each prematch drop for N seconds and sends it only if the price has not bounced back. What it filters, what it costs, how to set it.
The prematch drop stream has a setting the live stream does not: recheck=N. Set it, and each detected drop is held for N seconds, then sent only if the price has not bounced back in that window, as the SSE setup guide documents, checked 2026-10-02. It is a server-side patience filter, and for twitchy prematch markets it removes a whole category of false alarms before they reach your code.
The problem it solves
Prematch prices on quieter markets wobble. A selection drifts to your threshold, hangs there for a few seconds, and recovers when a single order is absorbed. Without recheck, every wobble that crosses min_drop becomes an alert, and your dedupe and cooldown machinery spends itself on moves that never lasted.
With recheck set, the stream waits out the wobble. The price dipped, the price recovered, and nothing reaches you.
What it costs: N seconds of timing
The trade is speed for certainty. A real 5% move with recheck=30 arrives half a minute after it happened. For a prematch workflow, where the gap at other books tends to persist longer than a few seconds, that delay is usually cheap. For anything where seconds decide, it is not, and the setting belongs to the prematch stream for a reason: by the time a live price is confirmed, the play that caused it is often already over.
Set N to the longest delay your reaction can afford. If your alerts feed a human reading a chat, 30 to 60 seconds changes nothing. If they feed a model that acts immediately, keep N small and accept more noise downstream.
What recheck does not do
Three things remain yours. The threshold: min_drop still gates the size of the fall before recheck ever starts timing. The dedupe: a confirmed move that keeps falling will alert again as it crosses fresh thresholds, and the keys and cooldowns from the dedupe guide decide what repeats. The filter by sport or market: the stream sends what passes, and your rules still sort it.
Think of recheck as the stream asking one question on your behalf, is this move still real after N seconds, before your code asks any of its own.
A quiet way to measure it
Log for a week with recheck off, then a week with it on, at the same threshold. The fall in alert count is the noise you were paying attention to; the moves that still arrive are the ones the setting exists for. The drop alerts guide covers the threshold side of the same tuning loop.
One parameter, N seconds of patience, and the prematch stream tells you about moves instead of wobbles.