The closest alternative to Solar Pro 3 is Qwen3 Max — comparable intelligence (26.1 vs 25.9); for a cheaper option, MiMo-V2.5 runs $0.140/M vs $0.150/M; for more speed, Mercury 2 hits 590 t/s; and the best open-weight substitute is MiniMax M3.
Qwen3 Max is the closest alternative to Solar Pro 3, with an Intelligence Index of 26.1 (Solar Pro 3 scores 25.9) at $0.780 per million input tokens.
Yes — MiMo-V2.5 costs $0.140 per million input tokens versus $0.150 for Solar Pro 3, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to Solar Pro 3 — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.