OpenAI Makes Its Fast, Cheap Decisions API Generally Available

On October 22, 2026, OpenAI made its Decisions API generally available. It’s a dedicated endpoint for the many small, bounded choices that apps and AI agents make inside a workflow: how to classify an input, where to route a request, or which action to take next.

How it works

The Decisions API is built with GPT-6 Luna. Developers define a question and its allowed answers, then pass context as text, images, or native JSON. It returns one of three answer types:

• Predicate: a probability from 0 to 1 that a condition is true, such as whether a product has visible damage.
• Choice: one of your predefined options, along with probabilities and confidence.
• Score: a rating against ordered levels in a rubric, such as damage severity.

OpenAI says this makes near real-time decisions up to 10x faster than GPT-6 Luna through the Responses API.

What’s new since the beta

Since its public beta, OpenAI has added a native GPT-Live integration for voice apps, prompt caching, inference residency in the US and EU, native JSON inputs, images in question instructions, and up to 400 questions per request, twice the previous limit.

Pricing

The API costs $0.10 per million input tokens and $0.01 per million cached input tokens. There are no output-token charges. Zero Data Retention is available to eligible customers.

Early users

OpenAI’s post quotes several customers. Box says it got about 5x faster route selection in an evaluation with the same accuracy as the Responses API. Datadog says it saw 40x faster p95 latency than available frontier models with comparable accuracy. Ramp reports 4x faster and 30% cheaper cost attribution compared with GPT-6 Luna. Sierra says it runs at under 280 ms p95, about 3x faster and 90% cheaper per call than its previous approach. Speak says time to next action in GPT-Live dropped from 1.4 seconds to 0.13 seconds. These are the companies’ own figures.