OpenAI lowers GPT-5.6 Sol API costs for developers

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OpenAI has cut API pricing for GPT-5.6 Sol, lowering the cost of its frontier AI model as competition increasingly shifts from model capability alone to price-performance. The promotional pricing, introduced on August 21, will remain available at least through November 21, 2026.

GPT-5.6 Sol now costs $4 per million input tokens, down from $5, while output pricing has fallen from $30 to $20 per million tokens. That represents a 20% reduction for input and a 33.3% cut for output, potentially delivering larger savings for coding, agentic and other generation-heavy workloads. Cached input has also fallen to $0.40 per million tokens.

OpenAI said it was “dropping API and credit pricing… by over 20%” as it continues improving efficiency. The lower rates are also rolling out to eligible credit-based usage in ChatGPT Work and Codex, while Plus, Pro and Business subscription pricing remains unchanged.

The move follows OpenAI’s July 30 reductions for GPT-5.6 Terra and Luna. Terra’s API pricing fell to $2 per million input tokens and $12 for output, while Luna dropped to $0.20 and $1.20 respectively. OpenAI said those earlier savings followed improvements that reduced serving costs by 20% and improved token-generation efficiency by more than 15%.

For developers and enterprises, the implication is practical: advanced AI workloads can become cheaper to deploy at scale. AWS said the reduced pricing gives customers “more room to experiment and scale” existing workloads.

The qualification is important. Sol’s new rates are promotional, and OpenAI has not said what pricing will apply after November 21. Businesses building unit economics around the discount should therefore treat the current rate as temporary rather than permanent.