OpenAI cuts GPT-5.6 Luna price 80%, adds Fast mode for Sol
By Steven Van ·
Terra drops 20% too, and Auto-review now runs on Luna at roughly a tenth of the previous cost.
OpenAI announced a round of price and speed changes across its GPT-5.6 lineup, framed as a direct commitment to the price-performance frontier: cost efficiency, capability, and speed all moving in the same direction at once. GPT-5.6 Luna drops 80% in price, GPT-5.6 Terra drops 20%, and GPT-5.6 Sol gets a new Fast mode in the API.
Where the savings show up
The lower Luna and Terra prices aren't limited to raw API calls, they're reflected in how usage is counted in Codex and ChatGPT Work, so the same subscription or usage allocation goes further without any change on the user's end. OpenAI also upgraded Auto-review in the ChatGPT app and Codex CLI from GPT-5.4 to GPT-5.6 Luna. Combined with Luna's new pricing, OpenAI expects Auto-review to cost roughly 10x less to run, a meaningful shift for anyone leaning on automated code review as part of an agentic workflow.
A faster option for Sol, at a cost
Alongside the price cuts, GPT-5.6 Sol gets a Fast mode in the API: up to 2.5x the speed of standard processing, at 2x the standard price, with no change in intelligence. That mirrors a pattern other labs have adopted recently, offering the same model at a latency-optimized tier for workloads where speed matters more than per-token cost, alongside the default tier for everything else.
Why OpenAI frames this as efficiency, not just discounting
OpenAI's own explanation ties the price cuts to real efficiency gains made with the help of GPT-5.6 Sol itself, passing those gains back to developers rather than banking them as margin. The company has been shipping frequent model updates at a fast clip, and this release continues that cadence: rather than a single flagship jump, it's a tuning pass across the existing GPT-5.6 family that changes what the same budget buys.
Ripple effects across the ecosystem
Platforms built on top of OpenAI's API models felt the change immediately. Unity AI assistant Bezi called the cut a big deal for its own users, since Luna and Terra's lower prices pass straight through to whatever OpenAI-powered features Bezi runs on top of them.
Sources: OpenAI, OpenAI on X.