OpenAI-compatible chat

POST /v1/chat/completions takes a list of messages and returns the next assistant message. It is stateless: for a follow-up, send the earlier user and assistant messages again yourself.

Python

from openai import OpenAI

client = OpenAI(base_url="https://dummydomain/v1", api_key="YOUR_API_KEY")

history = [{"role": "user", "content": "Explain why leaves look green."}]
first = client.chat.completions.create(model="Fast", messages=history, max_tokens=512)
history.append({"role": "assistant", "content": first.choices[0].message.content})

history.append({"role": "user", "content": "Now explain it to a ten-year-old."})
second = client.chat.completions.create(model="Fast", messages=history)
print(second.choices[0].message.content)

JavaScript

import OpenAI from "openai";

const client = new OpenAI({ baseURL: "https://dummydomain/v1", apiKey: process.env.API_KEY });

const history = [{ role: "user", content: "Explain why leaves look green." }];
const first = await client.chat.completions.create({ model: "Fast", messages: history, max_tokens: 512 });
history.push({ role: "assistant", content: first.choices[0].message.content });

cURL

curl --fail-with-body "https://dummydomain/v1/chat/completions" \
  -H "Authorization: Bearer $API_KEY" -H 'Content-Type: application/json' \
  -d '{"model":"Fast","max_tokens":512,
       "messages":[{"role":"user","content":"Explain why leaves look green."}]}'

Streaming

Set stream: true. Replies arrive as server-sent events with choices[].delta, ending with data: [DONE]. Add stream_options: {"include_usage": true} to receive token usage at the end.

Python

stream = client.chat.completions.create(
    model="Fast", stream=True,
    messages=[{"role": "user", "content": "Write a two-line welcome note."}],
)
for chunk in stream:
    if chunk.choices and chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)

cURL

curl --no-buffer "https://dummydomain/v1/chat/completions" \
  -H "Authorization: Bearer $API_KEY" -H 'Content-Type: application/json' \
  -d '{"model":"Fast","stream":true,"messages":[{"role":"user","content":"Write a two-line welcome note."}]}'

Caution

A stream that ends with an error frame, or disconnects before [DONE], is not a complete answer. Don’t use partial text or run a partial tool call.

Parameters

Field	Notes
model	Instant, Fast, Smart or Genius (when your server has it)
messages	system, developer, user, assistant and tool roles
max_tokens / max_completion_tokens	Positive integer; if you send both, they must match
temperature	0 to 2
top_p	0 to 1
presence_penalty, frequency_penalty	−2 to 2
stop	A string or up to 4 strings
seed	Signed 64-bit integer
response_format	See Structured JSON output
tools, tool_choice, parallel_tool_calls	On tiers with capabilities.tools; your code runs the functions

n other than 1, functions, function_call and logprobs are refused.

Errors

Errors return an error object with message, type, code, param where relevant, and a request_id. Keep the X-Request-ID response header when you report a problem.

Status	What to do
400	Fix the request; the code and param say what is wrong
401	Check the key and that you are sending Authorization: Bearer
429	Wait for Retry-After if present, then retry with back-off
5xx	Retry with back-off, only if repeating the request is safe