OpenAI Cuts GPT-5.6 Luna and Terra Prices, Adds Fast Mode for Sol
OpenAI reduced GPT-5.6 Luna pricing by 80% and GPT-5.6 Terra pricing by 20%, introduced Fast mode for GPT-5.6 Sol (replacing Priority Processing), and said auto-review in the ChatGPT app and Codex CLI is moving from GPT-5.4 to GPT-5.6 Luna—aiming for ~10x cheaper auto-review.
OpenAI announced a set of price and speed changes for the GPT-5.6 family: GPT-5.6 Luna is 80% cheaper, GPT-5.6 Terra is 20% cheaper, and the API now offers Fast mode for GPT-5.6 Sol (replacing Priority Processing). (OpenAI)
OpenAI also said it is upgrading auto-review in the ChatGPT app and Codex CLI from GPT-5.4 to GPT-5.6 Luna, and that combined with Luna’s new price it expects auto-review to cost about 10x less. (OpenAIDevs on X, OpenAI)
Key takeaways
- Lower prices for Luna and Terra: OpenAI says Luna is 80% cheaper and Terra is 20% cheaper. (OpenAI)
- New published API prices (July 30): OpenAI lists Terra at $2 / $12 (input/output per million tokens) and Luna at $0.20 / $1.20 (input/output per million tokens). (OpenAI)
- Fast mode for Sol: OpenAI says Fast mode is up to 2.5x faster than Standard at 2x the Standard price, with no change in intelligence, and it replaces Priority Processing. (OpenAI)
- Compatibility note: OpenAI says existing API requests tagged
prioritywill continue to work and will automatically use Fast mode. (OpenAI) - ChatGPT/Codex subscriptions unchanged: OpenAI says subscription prices and quota budgets remain unchanged; Terra and Luna usage now consumes fewer credits. (OpenAI)
What changed (with numbers)
OpenAI framed this release as pushing the “price-performance frontier” by improving efficiency and passing those gains through to developers and teams. Concretely, it published:
API pricing
| Model | Input price | Output price | Notes |
|---|---|---|---|
| GPT-5.6 Terra | $2 per 1M tokens | $12 per 1M tokens | OpenAI says this is the API pricing starting July 30. (OpenAI) |
| GPT-5.6 Luna | $0.20 per 1M tokens | $1.20 per 1M tokens | OpenAI says this is the API pricing starting July 30. (OpenAI) |
OpenAI also says Sol pricing remains unchanged. (OpenAI)
Fast mode (Sol)
OpenAI says Fast mode for GPT-5.6 Sol is available in the API and replaces Priority Processing. (OpenAI)
According to OpenAI, Fast mode delivers up to 2.5x the speed of Standard processing at 2x the Standard price, with no change in intelligence. (OpenAI)
If you already use Priority Processing, OpenAI says your existing priority requests will keep working and will automatically route to Fast mode. (OpenAI)
Auto-review (ChatGPT app + Codex CLI)
OpenAI says it is upgrading auto-review in the ChatGPT app and Codex CLI from GPT-5.4 to GPT-5.6 Luna, and expects the combination of the model switch plus Luna’s new pricing to make auto-review about 10x cheaper. (OpenAIDevs on X)
What this means in practice
- If you run high-volume workflows, Luna’s new pricing is the headline change.
- If you want faster response times for latency-sensitive paths, Fast mode gives a paid speed tier for GPT-5.6 Sol without changing the model’s capability.
- If you use auto-review in ChatGPT or Codex CLI, OpenAI is signaling a substantial expected cost reduction (and likely wider viability for continuous agentic review loops), but the only specific figure shared is the “about 10x cheaper” expectation.
Sources
- OpenAI: Advancing the price-performance frontier with GPT-5.6 (Jul 30, 2026) — https://openai.com/index/advancing-the-price-performance-frontier-with-gpt-5-6/
- OpenAI post on X (Jul 30, 2026) — https://x.com/OpenAI/status/2082878156483219672
- OpenAI Developers post on X (Jul 30, 2026) — https://x.com/OpenAIDevs/status/2082878497043923265
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Frequently Asked Questions
What changed in GPT-5.6 pricing?
OpenAI says GPT-5.6 Luna is now 80% cheaper and GPT-5.6 Terra is now 20% cheaper. It also published new API prices: Terra at $2 per million input tokens and $12 per million output tokens, and Luna at $0.20 per million input tokens and $1.20 per million output tokens.
What is Fast mode for GPT-5.6 Sol?
OpenAI says Fast mode for GPT-5.6 Sol in the API replaces Priority Processing. OpenAI says it can be up to 2.5x faster than Standard processing at 2x the Standard price, with no change in intelligence. OpenAI also says requests tagged priority will automatically use Fast mode.
Did ChatGPT or Codex subscription prices change?
OpenAI says ChatGPT and Codex subscription prices and quota budgets remain unchanged, while Terra and Luna usage now consumes fewer credits.