Inference API

Call a System One model from your own code: send a state and a few typed questions, and get a calibrated probability for every option back in one request. The models are the ones with a live playground here, kept loaded by the System One Engine.

• Base URL: https://api.systemonemodels.tech
• Requests, answers and errors follow the HTTP binding of OpenDXP (POST /v1/systemone), so a client written for an OpenDXP server works here too.

Get an API key

Create one at Settings → API. A key starts with s1_pat_ and is shown once. It calls models and nothing else: it cannot publish, and it cannot see your private models, so a key that leaks from an app exposes nothing but your allowance of decisions. Keep it on your server, never in a web page. Tokens from systemone login can call models too.

Call a model from Python

pip install -U systemonemodels     # 0.4 or later
export SYSTEMONE_API_KEY=s1_pat_…

from systemone import Client

client = Client()  # reads SYSTEMONE_API_KEY; or Client("s1_pat_…")
result = client.decide(
    "nokia/anyjev",
    "Customer: I was charged twice and want my money back.",
    {
        "intent": {
            "type": "choice",
            "instructions": "What does the customer want?",
            "criteria": ["refund", "track delivery", "cancel order"],
        },
        "angry": {"type": "noul", "instructions": "The customer is angry."},
    },
)
print(result["answers"]["intent"]["choice"])   # refund
print(result["answers"]["angry"]["noul"])      # the probability that it is true

client.served_models() lists the models you can call, and client.usage() what is left of your plan.

Over HTTP

curl https://api.systemonemodels.tech/v1/systemone \
  -H "Authorization: Bearer $SYSTEMONE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "nokia/anyjev",
       "state": "Customer: where is my parcel?",
       "questions": {"intent": {"type": "choice",
                                "instructions": "What does the customer want?",
                                "criteria": ["refund", "track delivery", "cancel order"]}}}'

Field	Meaning
model	The model, as namespace/name
state	The situation to decide about: text, up to 8,000 characters
questions	1 to 8 questions, each under an id you choose (letters, digits, ., _, :, -)
checkpoint	Optional: one of the model's checkpoints; the first one answering when left out

Each question has a type and instructions:

• choice picks one of 2 to 20 options. criteria is a list of names, or {"name": "description, or null"}.
• score places the state on an ordered scale. criteria is a list of 2 to 10 levels, lowest first.
• noul asks whether the statement in instructions is true. criteria is left out, or {"false": "…", "true": "…"}.

The answer

{
  "model": "nokia/anyjev",
  "version": "0.2.0-qwen3-1.7b",
  "checkpoint": "f16",
  "answers": {
    "intent": { "type": "choice", "choice": "refund",
                "probabilities": { "refund": 0.93, "track delivery": 0.02, "cancel order": 0.05 } },
    "angry": { "type": "noul", "noul": 0.71 }
  },
  "usage": { "input_tokens": 212, "output_tokens": 0, "decisions": 2 },
  "latency_ms": 840.5
}

A score answer carries score, the expected level, with its legend and a probability per level. System One models answer without generating text, so output_tokens is always 0.

Which models

GET /v1/systemone/models lists the models you can call, with their state (ready; starting while one loads; offline), checkpoints and limits. It needs no key. A model can be called once it has a live playground, which its owner asks for from the model's Playground tab (how).

Plans and limits

A decision is one question answered, so a request with three questions uses three. A request the model could not answer costs nothing. Days and months are UTC.

Plan	Decisions	Requests
Free	500 a day	60 a minute
Developer	100,000 a month	600 a minute
Enterprise	By agreement	3,000 a minute

Every answer says what is left, in X-Quota-Limit, X-Quota-Remaining and X-Quota-Reset. GET /v1/usage, with your key or signed in, gives your plan and your calls by day, model and key; Settings → API shows the same. For the Developer or Enterprise plan, write to [email protected].

The models run on shared CPU servers today: answers take from tens of milliseconds (Laya, Julia 1) to several seconds (language models asked once per option order, like AnyJev).

Errors

The body has the registry's usual detail and code, and OpenDXP's error with a type:

{ "detail": "You have used today's 500 decisions on the Free plan. …",
  "code": "quota_exceeded", "errors": [],
  "error": { "type": "request_refused", "message": "You have used today's 500 decisions on the Free plan. …" } }

Status	code	What to do
400	validation_error	Fix the request; errors names the field
401	unauthorized	Send a valid key as Authorization: Bearer …
403	insufficient_scope	Use an API key: this token cannot call models
404	model_not_found, model_not_served	Check the name, or pick one from GET /v1/systemone/models
422	bad_question	The model cannot take this question; the message says why
429	rate_limited, quota_exceeded	Wait Retry-After seconds, or until your plan renews
503	starting, busy, timeout, api_paused	Try again after Retry-After seconds