GPT-5.6 in ChatGPT: Sol, Pro, Plans and Model Picker Guide

GPT-5.6 Arrives in ChatGPT

OpenAI's GPT-5.6 series brings a new tiered architecture to the ChatGPT experience, introducing multiple sub-models optimized for different tasks. Understanding these variants — Sol, Terra, and Luna — is essential for developers who want to maximize performance while managing costs.

Model Variants Explained

• GPT-5.6 Sol: The flagship variant with maximum reasoning capability and 258K context. Best for complex coding, mathematical proofs, and multi-step planning.
• GPT-5.6 Terra: Balanced performance and cost. Ideal for general development tasks, content creation, and business analysis.
• GPT-5.6 Luna: Cost-optimized variant with the same architecture but lower latency. Perfect for high-volume applications and simpler queries.

Accessing via API

All GPT-5.6 variants are available through our proxy platform. Use model IDs gpt-5.6-sol, gpt-5.6-terra, or gpt-5.6-luna depending on your needs. The OpenAI-compatible interface ensures drop-in compatibility with existing code.