GPT-6.1 Terra

Google launched Gemini 4 Hydrogen, the speed-and-cost-focused tier of its Gemini 4 family, replacing Gemini 3.8 Flash and positioned against Anthropic's Claude Sonnet 5.5 and OpenAI's GPT-6.1 Terra. Priced at $1.5/$7.5 per million input/output tokens, it topped 7 of 10 Google-published benchmarks, including a 13.5% SWE-sweep score versus 3.1% for Sonnet 5.5. It is rolling out across Gemini App paid tiers, AI Studio, the Gemini API and Antigravity, with free-tier developer access.