A Decisions API returns an answer your code can handle
A Decisions API is an interface for bounded decisions inside an application. Instead of asking for an open-ended paragraph, your service supplies context (state) and defines the question and allowed answer shape. The response can then be validated and handled by ordinary application code.
Decisions API at decisions-api.pro exposes a System One endpoint backed by the configured Jev decision model. One request can contain several independent questions about the same state. This is useful when a product needs classification, routing, a rubric score, or a yes/no signal as part of a larger workflow.
Choice, Noul, and Score answer different question types
Choice selects one key from options you define and can include a probability distribution over those options. Noul expresses a yes/no judgment as a probability. Score places the state on an ordered scale you provide and returns a score with level probabilities. Choose the primitive that matches the decision boundary in your code.
These outputs are signals, not guarantees. Validate the response, set thresholds from your own labeled cases, and route low-confidence or high-impact cases to human review. Keep permissions, policy enforcement, and consequential actions in your application.
A request starts with state and named questions
Keep state relevant to the decision and make criteria explicit. Named question IDs make it straightforward to map each answer back to a code path. The current endpoint accepts a state plus one to eight typed questions.
POST https://decisions-api.pro/v1/systemone
Authorization: Bearer <API_KEY>
Content-Type: application/json
{
"state": "Checkout errors rose after release 4.8.1; the error budget is nearly exhausted.",
"model": "jev-latest",
"questions": {
"next_step": {
"type": "choice",
"instructions": "What should the on-call team do?",
"criteria": {
"pause": "Pause rollout and investigate",
"rollback": "Restore the previous release",
"monitor": "Continue while monitoring metrics"
}
}
}
}From free online test to production integration
Use the free online Decisions API playground to inspect a representative request and its structured response. Then follow the API documentation for authentication, request fields, response handling, errors, and usage. Keep API keys server-side and verify model behavior on a test set that reflects your product before connecting outputs to production actions.