Advancing the price-performance frontier with GPT-5.6

OpenAI cut prices for GPT-5.6 Luna and Terra, with Luna down 80% and Terra down 20%.

The company also added Fast mode for GPT-5.6 Sol in the API, replacing Priority Processing.

Fast mode offers up to 2.5x faster speed at twice the price, giving users more control over speed-cost tradeoffs.

The lower pricing also applies to Codex and ChatGPT Work, alongside ongoing efficiency gains in serving and agent workflows.