The closest alternative to GPT-5 Pro is GPT Chat Latest — comparable intelligence (— vs —); for a cheaper option, Claude Fable 5 runs $10.00/M vs $15.00/M; for more speed, Morph V3 Large hits 2.6k t/s; and the best open-weight substitute is MiniMax M3.
GPT Chat Latest is the closest alternative to GPT-5 Pro, with an Intelligence Index of — (GPT-5 Pro scores —) at $5.00 per million input tokens.
Yes — Claude Fable 5 costs $10.00 per million input tokens versus $15.00 for GPT-5 Pro, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to GPT-5 Pro — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.