The closest alternative to GPT-5 is Hy3 preview — comparable intelligence (41.9 vs 42.0); for a cheaper option, MiniMax M3 runs $0.300/M vs $1.25/M; for more speed, GLM 4.7 hits 427 t/s; and the best open-weight substitute is MiniMax M3.
Hy3 preview is the closest alternative to GPT-5, with an Intelligence Index of 41.9 (GPT-5 scores 42.0) at $0.063 per million input tokens.
Yes — MiniMax M3 costs $0.300 per million input tokens versus $1.25 for GPT-5, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to GPT-5 — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.