GUIDE · UPDATED SEPTEMBER 30, 2026
The OpenAI Decisions API
At DevDay on September 29, 2026, OpenAI announced a Decisions API built on a specialised version of GPT-6 Luna. Instead of generating text, it answers questions that have a finite set of developer-defined answers, from text or image context, and returns the chosen answer. OpenAI positions it for classifying content, routing requests and choosing an agent's next action, with answers in a fraction of a second.
Availability
At announcement the OpenAI Decisions API is in limited preview, with a broader release described as coming. Accounts without preview access receive an error saying the Decision API is not enabled, and the public request contract and pricing had not been published when this guide was written.
Getting the same pattern today
This site is an independent Decisions API built on the official OpenAI API. It follows the same idea — you define the answers, the model picks one — and adds a probability for every option. It is self-serve: sign in, try the playground with free runs, create an API key and pay only for input tokens.
| OpenAI Decisions API | This Decisions API | |
|---|---|---|
| Status | Limited preview | Available now |
| Model | Specialised GPT-6 Luna | OpenAI GPT-4.1 mini / nano |
| Input | Text or image context | Text, JSON and image context |
| Output | Predefined answer | Predefined answer + probability per option |
| Access | OpenAI account with preview access | Self-serve key, free runs to start |
Decisions API (decisionsapi.pro) is not affiliated with or endorsed by OpenAI. OpenAI and GPT are trademarks of OpenAI. Details about the OpenAI product are from its public DevDay announcement and may change.