GPT-5.6 Luna is the fastest, most cost-optimized model in the GPT-5.6 family, released July 9, 2026, built for high-volume and latency-sensitive workloads.
- Fastest, most cost-optimized GPT-5.6 tier for high-volume, latency-sensitive workloads.
- Supports a 1,050,000-token context window and up to 128,000 max output tokens.
- Configurable reasoning effort from none to xhigh.
- Full tool support including web search, image generation, and JSON mode.
- Pricing is $0.20 per 1M input tokens and $1.20 per 1M output tokens.
Web Search
Search the web for current info.
JSON Mode
Output responses in valid JSON format.
Image Generator
Generate images from text prompts.
Model Information
Supported Formats
GPT 5.6 SolGPT-5.6 Sol is OpenAI's flagship model in the GPT-5.6 family, released July 9, 2026, for the most complex professional work spanning software engineering, long-horizon research, agentic tool use, and careful result refinement.
GPT 5.6 TerraGPT-5.6 Terra balances capability and cost efficiency for everyday production workloads in the GPT-5.6 family, released July 9, 2026.
GPT 5.5OpenAI's most advanced model released April 2026. GPT-5.5 is recommended for most reasoning workloads, combining frontier intelligence with configurable reasoning effort (none → xhigh). Available in API, Codex, and ChatGPT.