Chess's one-game-a-day cap is a two-core bill, and WebAssembly moves it onto your laptop

The arithmetic in the post is rounded generously. Eighty positions at two seconds each is 160 seconds, not quite the three minutes claimed ^[1], and a thousand daily reviewers therefore cost about 44 core-hours a day rather than 50 ^[2]. The quibble is worth making because of where it lands: the entire free tier for a thousand people fits inside two cores running flat out around the clock ^[3]. That is one small instance. Nobody writes a quota policy to protect one small instance.

The cap is priced for the day the free tier works. The same 160 seconds across a hundred thousand daily reviewers is roughly 4,440 core-hours a day, about 185 cores that exist purely to give something away ^[4]. And because each position belongs to one player's game, none of that work is reusable across users ^[4], so the bill scales with headcount in a straight line with no cache to bend it.

Putting Stockfish in a Web Worker does delete the line item. The server ships static files and never sees a chess position ^[7], and with no per-user cost there is nothing to meter and therefore nothing to cap ^[8]. What it does not delete is the 160 seconds. Those are still spent, now in one browser tab, by a person watching a progress bar on a machine whose speed you did not choose. On chessdream.app that spend is also the worst version of itself: the author checked while writing the post and found the site does not send the cross-origin isolation headers, so every analysis runs single threaded and the depth 15 default is doing more work than the strength it returns ^[15]. Threads are the obvious lever, and they need SharedArrayBuffer, which since Spectre browsers only hand to a cross-origin isolated page carrying `Cross-Origin-Opener-Policy: same-origin` and `Cross-Origin-Embedder-Policy: require-corp` ^[14].

The quieter trade is observability. Server-side metering is also server-side logging, and the browser gives you neither. Every failure mode described in the post returns a plausible number instead of an error. Read the wrong `info` line and a depth 4 evaluation is presented as depth 15 ^[9]. Pass `score mate 3` through the same divide-by-100 as a centipawn score and a forced win renders as 0.03, dead level on the graph ^[10]. Forget `removeEventListener` and every position after the first carries listeners from all its predecessors, resolving promises that already resolved, silently, without throwing ^[12]. Forget to terminate the Worker and you leak one per analysis on the visitor's machine rather than yours ^[13].

None of that argues for keeping the quota. It argues that the two costs are not the same shape. A CPU budget is a number you can see going up. A client-side engine converts it into wrong evaluations on other people's hardware and a wait time you learn about from complaints. The trade is still good at a hundred thousand users, where the alternative is 185 cores ^[4]. At a thousand, where the alternative is two ^[3], the honest reason to move the engine into the browser is that you no longer have to defend a quota, not that you saved the money.