Evaluate questions

Send any JSON state and one to 512 typed questions. Each question gets an answer with calibrated probabilities under the same id.

Billing: only a 200 is billed, at the per-input-token price.
Unknown keys: top-level keys Drex doesn't know are ignored.

Checks run in this order and stop at the first failure:

API pause (529)
Key and credit (401, 402)
Rate limits (429, 529)
Body validation (422)
Model evaluation (422 for too many tokens, 529 when the model service does not answer within 55 seconds)

Authorization

bearerAuth

AuthorizationBearer <token>

Your API key from the dashboard's API Keys page: nace_sk_ followed by 43 URL-safe characters (A-Z, a-z, 0-9, _ and -), shown once when you create it. Send it as Authorization: Bearer nace_sk_... Any other value returns 401 authentication_error. An account can hold at most 3 active keys.

In: header

Request Body

application/json

TypeScript Definitions

Use the request body type in TypeScript.

Unknown top-level keys are ignored.

state*State

Any JSON value: string, number, boolean, null, object, or array. Drex passes it to the model as is. The key must be present, but null is accepted.

questions*

Map of question id to question. Ids must be non-empty and not whitespace only. At least 1 and at most 512 questions. state and questions, serialized together as JSON, must be at most 1048576 bytes. The state must fit the model's state limit, and the state plus the longest question must fit its row limit: 131,072 and 139,264 tokens for drex-v1.5, 32,768 and 32,768 for drex-v1.0. Text only: images, audio, video and PDFs (base64 data URLs, raw base64 files, or OpenAI, Anthropic and Gemini media content parts) anywhere in state or questions are rejected with a 422.

Properties1 <= properties <= 512

model?string

Optional. A pinned version id, such as drex-v1.0 or drex-v1.5, is always served by that version. The alias drex-latest is served by the version it points to, currently drex-v1.5; it moves to a newer version only on an announced date. GET /v1/models lists each alias with its alias_for. A retired id, such as drex-v1.1, is served by its successor, and the response model reports the successor; GET /v1/models lists it with alias_for set. A registered id that is not available yet returns 422 with issue path model. Any other drex-* name, or a legacy nacedm-* name, is served like drex-latest, as is a request without model. Any other value, including a TypeSafe SDK default such as jev-latest, returns 422 with issue path model.

Match^(?:drex|nacedm)-[A-Za-z0-9.-]+$

Response Body

`application/json`

curl -X POST "https://example.com/v1/systemone" \  -H "Content-Type: application/json" \  -d '{    "model": "drex-v1.0",    "state": "I was charged twice for my March invoice. Please refund one of the charges.",    "questions": {      "category": {        "type": "choice",        "instructions": "What is this support ticket about?",        "criteria": {          "billing": "Payments, invoices, refunds, or charges",          "technical": "Bugs, errors, or outages",          "account": "Login, profile, or permissions",          "other": null        }      },      "sentiment": {        "type": "score",        "instructions": "How upset is the customer?",        "criteria": [          "Calm",          "Mildly annoyed",          "Frustrated",          "Angry"        ]      },      "wants_refund": {        "type": "noul",        "instructions": "Is the customer asking for a refund?"      }    }  }'

{  "model": "drex-v1.0",  "answers": {    "category": {      "type": "choice",      "choice": "billing",      "confidence": 0.986,      "probabilities": {        "billing": 0.9895,        "technical": 0.005,        "account": 0.0006,        "other": 0.0049      }    },    "sentiment": {      "type": "score",      "score": 1.5306,      "legend": [        "Calm",        "Mildly annoyed",        "Frustrated",        "Angry"      ],      "probabilities": {        "0": 0.1572,        "1": 0.3516,        "2": 0.2946,        "3": 0.1966      },      "confidence": 0.7183    },    "wants_refund": {      "type": "noul",      "noul": 0.9868    }  },  "usage": {    "input_tokens": 106,    "output_tokens": 212  },  "evaluation_time_ms": 142.6,  "request_id": "req_0123456789abcdef0123456789abcdef"}

Evaluate questions

AuthorizationCopy Anchor Link

Request BodyCopy Anchor Link

Response BodyCopy Anchor Link

200application/json

401application/json

402application/json

422application/json

429application/json

500application/json

529application/json

Answers for the support ticket example (real capture)

Answers for the object-state example (real capture)

Authorization

Request Body

Response Body

`application/json`

`application/json`

`application/json`

`application/json`

`application/json`

`application/json`

`application/json`