OpenAI compatibility

NinjaChat exposes an OpenAI-compatible /chat/completions endpoint. Point any OpenAI SDK at NinjaChat by setting two things:

Base URL: https://www.ninjachat.ai/api/v1
API key: your nj_sk_... key

Choose a NinjaChat model ID. Chat Completions supports OpenAI-style messages, streaming, tools and errors; available parameters depend on the model.

Starting a new integration? The official NinjaChat SDKs add typed routing, images, video polling, usage, request traces, and webhook helpers. Keep the OpenAI SDK when you want the smallest possible migration.

from openai import OpenAI

client = OpenAI(
    base_url="https://www.ninjachat.ai/api/v1",
    api_key="nj_sk_YOUR_API_KEY",
)

resp = client.chat.completions.create(
    model="gpt-5.6-luna",
    messages=[{"role": "user", "content": "Hello!"}],
)
print(resp.choices[0].message.content)

import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://www.ninjachat.ai/api/v1",
  apiKey: "nj_sk_YOUR_API_KEY",
});

const resp = await client.chat.completions.create({
  model: "gpt-5.6-luna",
  messages: [{ role: "user", content: "Hello!" }],
});
console.log(resp.choices[0].message.content);

Env-var setup

The OpenAI SDKs also pick up OPENAI_API_KEY and OPENAI_BASE_URL from the environment, so you can skip the constructor arguments entirely:

export OPENAI_API_KEY='nj_sk_YOUR_API_KEY'
export OPENAI_BASE_URL='https://www.ninjachat.ai/api/v1'

Python

from openai import OpenAI

client = OpenAI()  # reads OPENAI_API_KEY / OPENAI_BASE_URL

Use www.ninjachat.ai, not the bare ninjachat.ai apex domain. The apex redirects and strips the Authorization header along the way, so every request would arrive unauthenticated.

What works

Any model — pass any model ID, or ninja/auto to let NinjaChat pick.
Streaming — set stream: true for token-by-token server-sent events.
Tool calling — standard tools / tool_choice with function.parameters.
Sampling — temperature, top_p, max_tokens (or max_completion_tokens), stop, seed, frequency_penalty, presence_penalty.

# Streaming
for chunk in client.chat.completions.create(
    model="ninja/auto",
    messages=[{"role": "user", "content": "Write a haiku about the sea."}],
    stream=True,
):
    print(chunk.choices[0].delta.content or "", end="")

/api/v1/chat/completions is the OpenAI-compatible message interface. For new native integrations, use /api/v1/responses; both share authentication, routing, and billing.

What’s rejected

The request schema is strict. Standard OpenAI SDK fields that have no effect on NinjaChat are dropped silently; anything that would change the meaning of the request fails with a 400 instead of being ignored:

You send	What happens
A field NinjaChat doesn’t know	`400 unsupported_parameter` — the message names the field
`max_tokens`	Folded into `max_completion_tokens`. If you send both they must match, or you get `400 conflicting_parameters`
`n` other than `1`	`400 unsupported_value` — send separate requests when you need several choices
`logprobs: true`	`400 unsupported_parameter` (`logprobs: false` is ignored)
Non-empty `logit_bias`	`400 unsupported_parameter` (an empty object is ignored)
`metadata`	Ignored on `/chat/completions`, unless it isn’t an object or has more than 32 keys — `400 invalid_parameter`
`model: "auto"`	Accepted as an alias of `ninja/auto`; the response reports the canonical id
`model: "ensemble"`, `auto-fast`, `a>b` chains, `model:suffix`	`400 invalid_model` — retired syntax. Use `models` for ordered fallbacks and `routing` for strategy and providers

NinjaChat extras

The native Responses API adds optional features OpenAI doesn’t have — smart routing, fallbacks, spend controls, explicit provider policy, and per-response cost_usd and request traces. Adopt the official NinjaChat SDK when you need those typed primitives.

Get Started

Chat

Orchestration

Production

Media & search

Reference

Env-var setup

What works

What’s rejected

NinjaChat extras

​Env-var setup

​What works

​What’s rejected

​NinjaChat extras

Env-var setup

What works

What’s rejected

NinjaChat extras