The closest alternative to GLM 4.5 Air is GPT-5.4 Mini — comparable intelligence (23.3 vs 23.2); for a cheaper option, Nemotron 3 Ultra (free) runs Free/M vs $0.125/M; for more speed, Mercury 2 hits 456 t/s; and the best open-weight substitute is MiniMax M3.
GPT-5.4 Mini is the closest alternative to GLM 4.5 Air, with an Intelligence Index of 23.3 (GLM 4.5 Air scores 23.2) at $0.750 per million input tokens.
Yes — Nemotron 3 Ultra (free) costs Free per million input tokens versus $0.125 for GLM 4.5 Air, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to GLM 4.5 Air — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.