Beside the lead
GLM-5.3-Flash went back to list price, and both halves of the bill doubled
Z.ai’s half-price promotion on its cheap tier ended at midnight Beijing time on 9 September.
Z.ai’s promotional rate on GLM-5.3-Flash expired at the end of 9 September. Input now lists at $0.15 per million against the promotional $0.075. Output lists at $0.50 against $0.25.
The cached-input rate doubled with everything else, $0.015 to $0.03, but it held its ratio at one fifth of input. A workload that reuses a long prefix therefore absorbs proportionally less of the rise than one that does not, which is the only part of this bill you still control.
The deadline was published as 24:00 on 9 September in UTC+8. A team billing in UTC watched the price change eight hours before the date they had written in the calendar.
What it changes If GLM-5.3-Flash sits anywhere in your routing table, your cost model for it is now exactly twice wrong. Re-run the comparison against the other cheap tiers before assuming it still wins on price.
The doubled prices are read on Z.ai’s own rate card. The precise expiry timestamp comes from a third-party price tracker and was not confirmed against a dated vendor notice; the card itself prints no publication date.