OpenAI has launched an aggressive price war against lower-cost Chinese rivals, slashing prices for its latest GPT-5.6 model line-up by up to 80 per cent. In a post on X on Thursday, CEO Sam Altman announced an 80 per cent drop in developer pricing for the lightweight GPT-5.6 Luna model, bringing API costs down to US$0.20 per million input tokens and US$1.20 per million output tokens. The San Francisco-based company also cut rates for its mid-tier GPT-5.6 Terra model by 20 per cent, to US$2 per million input tokens and US$12 per million output tokens, while introducing a “fast mode” for its flagship GPT-5.6 Sol that it said would boost performance speed up to 2.5 times. The trio of models was introduced earlier this month. OpenAI’s price cuts instantly propelled GPT-5.6 Luna into the “most attractive” tier in intelligence-per-dollar rankings by research firm Artificial Analysis, placing it above Chinese rivals such as Zhipu AI’s GLM-5.2 and MiniMax’s M3. The move highlights mounting pressure on Western technology giants as open-weight and accessible Chinese alternatives win over international developers with aggressive pricing and rapidly improving capabilities.