I built a tool that catches an active Steam rating decline before it snowballs (and tells you why)

The problem Steam's "Overwhelmingly Positive" badge is an all-time average. It can stay green for weeks after a patch, a pricing change, or a broken launch actually tanks a game's rating. Most devs find out from an angry tweet or a Reddit thread, not from Steam itself. I'd already built a similar review-mining tool for the App Store (a "copy+10%" market-research Actor — different post, different audience). Same week, I wondered: does Steam expose anything as clean as Apple's public RSS/Lookup endpoints? Turns out yes — better, actually. What Steam gives you for free Two public, zero-auth endpoints: https://store.steampowered.com/appreviews/<appid>?json=1&filter=recent https://store.steampowered.com/appreviewhistogram/<appid>?l=english The first gives you individual reviews with voted_up (boolean, no star-rating math needed), playtime_at_review , refunded , written_during_early_access — much richer than I expected. The second gives you a rolling histogram of recommendations_up / recommendations_down per period (weekly for active games, monthly for older ones), which is the actual key to detecting a real decline instead of noise. The bug that mattered I first tried Steam's documented day_range parameter to window the query_summary to "last N days." It doesn't do anything — I tested it against a game with 800K+ reviews spanning two years, day_range=30 and no day_range at all returned byte-identical totals. Not documented as broken anywhere I could find, so noting it here in case it saves someone else the debugging time. The appreviewhistogram endpoint is the actual fix: compare the most recent period's positive % against a baseline of prior periods, with a minimum-volume gate (I use 20 reviews/period) so a slow week on a small indie title doesn't get mistaken for a crisis. Real result Ran it against a game that had a rough launch week. Flagged an active decline immediately, and the negative-review sample broke down as 43% bugs/performance + 18% server issues — i.e., a