Replit debuts Free Mode powered by OpenAI’s GPT-5.6 Luna model

Replit just made its paid subscriptions a little more generous, though the naming convention might need some work. The coding platform’s new “Free Mode” runs on OpenAI’s GPT-5.6 Luna model and lets subscribers chat, brainstorm, and handle simple agent tasks without eating into their allocated AI credits. The feature, announced in a joint partnership update with OpenAI, is available to users on Replit’s $20/month Core tier and $100/month Pro tier. Despite the name, Free Mode doesn’t actually cost nothing. It just doesn’t cost extra. How Free Mode actually works Free Mode carves out a separate lane for low-stakes tasks using Luna, the most cost-efficient model in OpenAI’s GPT-5.6 family. Luna costs roughly 80% less to run than Sol, the top-tier variant in the same model family. That cost efficiency is what makes the economics work for Replit: they can offer unlimited lightweight interactions without hemorrhaging compute spend. When a user’s request escalates beyond what Free Mode can handle, the platform warns them before switching to paid mode. No surprise charges, no accidental token drain. The GPT-5.6 Luna backstory OpenAI released its GPT-5.6 model family on July 9, 2026, structu...