The closest alternative to Sonar Pro is Sonar Pro Search — comparable intelligence (— vs —); for a cheaper option, GPT-5.4 runs $2.50/M vs $3.00/M; for more speed, Morph V3 Large hits 3.1k t/s; and the best open-weight substitute is MiniMax M3.
Sonar Pro Search is the closest alternative to Sonar Pro, with an Intelligence Index of — (Sonar Pro scores —) at $3.00 per million input tokens.
Yes — GPT-5.4 costs $2.50 per million input tokens versus $3.00 for Sonar Pro, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to Sonar Pro — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.