Create a completion (legacy)

OpenAI deprecated this endpoint. It exists so older SDK pins and scripts keep working — use /v1/chat/completions for anything new.

What it is

An adapter over the chat endpoint, not a separate path. prompt becomes a single user message, and choices[].message.content comes back as choices[].text. Models, pricing, streaming, failover and usage.cost are identical, because the request goes through exactly the same pipeline.

from openai import OpenAI

client = OpenAI(api_key="ky-...", base_url="https://api.kymaapi.com/v1")

r = client.completions.create(
    model="qwen3.7-flash",
    prompt="Write a haiku about routing",
    max_tokens=64,
)
print(r.choices[0].text)

Three things return 400 instead of guessing

You sent	Why it is refused
`prompt: ["a", "b"]`	In the original API that means two independent completions. Concatenating them would return one answer where you expect two — send one request per prompt.
`suffix`	Fill-in-the-middle. No chat model does it, so honouring it would return a plausible completion that is wrong for the purpose.
`echo` and `stream`	`echo` prepends your prompt, which has nowhere to go in a token stream without inventing a frame you did not ask for.

best_of and logprobs are accepted and ignored — their absence is visible in the response, so there is nothing to guess about.

Streaming

Supported, in the legacy chunk shape:

data: {"id":"...","object":"text_completion","choices":[{"text":"One","index":0,"logprobs":null,"finish_reason":null}]}

A frame that carries only a role or a tool call has no text and no finish_reason, so it is dropped rather than emitted as an empty chunk.

​What it is

​Three things return 400 instead of guessing

​Streaming

What it is

Three things return 400 instead of guessing

Streaming