The closest alternative to o4 Mini is Claude Sonnet 4 — comparable intelligence (33.0 vs 33.1); for a cheaper option, MiniMax M3 runs $0.300/M vs $1.10/M; for more speed, gpt-oss-120b (free) hits 554 t/s; and the best open-weight substitute is MiniMax M3.
Claude Sonnet 4 is the closest alternative to o4 Mini, with an Intelligence Index of 33.0 (o4 Mini scores 33.1) at $3.00 per million input tokens.
Yes — MiniMax M3 costs $0.300 per million input tokens versus $1.10 for o4 Mini, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to o4 Mini — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.