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One AI API Key

StepFun · Step · Fast

StepAudio 3 Chat Preview

FreeNew

Free StepFun audio-chat model that reasons over a request and streams an answer on the OpenAI chat endpoint.

Model id

stepaudio-3-chat-preview:free

Price per 1M tokens

Input
$0.00
Output
$0.00
Cached input
Not offered

Free while the promotion runs.Models on the free lane (ids ending in :free) carry no rate of their own and share one allowance: 100 requests and 5,000,000 tokens a day for every account, in Chat and through the API. No balance and no card are needed: the $10 sign-up credit pays for priced models first, and once it is gone the models that bill $0 keep their daily requests. A paid subscription, a coupon or the owner raising your account is the only way past the daily number.

Added here 12 Nov 2026 — read the changelog for what changed and why.

1 credit = $1 of usage. All rates

Start using StepAudio 3 Chat Preview

Set ONEAIAPIKEY_API_KEY to a key from your console, then run any example. Streaming is on so long answers are not cut off by idle-connection timeouts.

curl https://api.oneaiapikey.com/v1/chat/completions \
  -H "Authorization: Bearer $ONEAIAPIKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "stepaudio-3-chat-preview:free",
    "stream": true,
    "messages": [{"role": "user", "content": "Label this support ticket as billing, bug or feature request, one word only: I was charged twice this month."}]
  }'
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.oneaiapikey.com/v1",
    api_key=os.environ["ONEAIAPIKEY_API_KEY"],
)

stream = client.chat.completions.create(
    model="stepaudio-3-chat-preview:free",
    messages=[{"role": "user", "content": "Label this support ticket as billing, bug or feature request, one word only: I was charged twice this month."}],
    stream=True,  # recommended for long outputs
)
for chunk in stream:
    if chunk.choices and chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.oneaiapikey.com/v1",
  apiKey: process.env.ONEAIAPIKEY_API_KEY,
});

const stream = await client.chat.completions.create({
  model: "stepaudio-3-chat-preview:free",
  messages: [{ role: "user", content: "Label this support ticket as billing, bug or feature request, one word only: I was charged twice this month." }],
  stream: true,
});

for await (const chunk of stream) {
  process.stdout.write(chunk.choices[0]?.delta?.content ?? "");
}

More: quickstart · API reference · try it in Chat first

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Real tokens served through this gateway, updated every 5 minutes. Ranked by usage, not quality.

Full ranking insights

Step line-up

StepAudio 3 Chat Preview or Step 5 Preview or Qwen3.8 27B Groq?

Of the 2 Step models on this site, Step 5 Preview is the step up from StepAudio 3 Chat Preview, and nothing in the family sits below it. Qwen3.8 27B Groq from Qwen is the closest-priced fast-tier model from another vendor. Each comparison lists the published rates and limits, then what favours each side.

StepAudio 3 Chat PreviewvsStep 5 Preview

Pick StepAudio 3 Chat Preview when

  • you want it at no cost while its promotion runs.
  • the work is voice-style chat, reasoning replies and preview trials, which this catalogue lists for StepAudio 3 Chat Preview and not for Step 5 Preview.

Pick Step 5 Preview instead when

  • StepAudio 3 Chat Preview falls short and you want the flagship model of the pair.
  • StepAudio 3 Chat Preview does not list Tools, Vision, Structured output and Prompt caching and your code depends on it.
  • your workload looks like agents, software engineering and research, labels the catalogue gives Step 5 Preview only.

StepAudio 3 Chat PreviewvsQwen3.8 27B Groq

StepAudio 3 Chat Preview and Qwen3.8 27B Groq bill at identical rates, so cost does not separate them.

Pick StepAudio 3 Chat Preview when

  • you rely on Reasoning, which Qwen3.8 27B Groq does not list.
  • the work is voice-style chat, reasoning replies and preview trials, which this catalogue lists for StepAudio 3 Chat Preview and not for Qwen3.8 27B Groq.

Pick Qwen3.8 27B Groq instead when

  • StepAudio 3 Chat Preview does not list Tools and JSON mode and your code depends on it.
  • your workload looks like coding, quick answers and agent tasks, labels the catalogue gives Qwen3.8 27B Groq only.

Use cases

What StepAudio 3 Chat Preview is listed for

The catalogue lists StepAudio 3 Chat Preview for voice-style chat, reasoning replies and preview trials.

Model your own traffic

  1. Voice-style chat

  2. Reasoning replies

  3. Preview trials

Overview

When StepAudio 3 Chat Preview fits

StepAudio 3 Chat Preview is a fast, low-cost model from StepFun, available here under the exact model id “stepaudio-3-chat-preview:free”. It is the entry point of the Step line-up here, below Step 5 Preview. StepFun has not published a release date we can cite; it has been available here since 12 Nov 2026.

StepFun documents reasoning for it.

It is free to use while the promotion runs: requests bill at $0. Models on the free lane (ids ending in :free) carry no rate of their own and share one allowance: 100 requests and 5,000,000 tokens a day for every account, in Chat and through the API. No balance and no card are needed: the $10 sign-up credit pays for priced models first, and once it is gone the models that bill $0 keep their daily requests. A paid subscription, a coupon or the owner raising your account is the only way past the daily number. After that it returns to the regular rate of $0.00 input and $0.00 output per million tokens.

It is served through the OpenAI-compatible format at https://api.oneaiapikey.com/v1, so any SDK or tool that lets you set a custom base URL, for example Codex CLI, Cursor and Cline, can use it. It is not offered on the Anthropic Messages endpoint; pick an Anthropic-format model for Claude Code.

Use StepAudio 3 Chat Preview at no cost.

It bills at $0 and never touches the balance. Models on the free lane (ids ending in :free) carry no rate of their own and share one allowance: 100 requests and 5,000,000 tokens a day for every account, in Chat and through the API. No balance and no card are needed: the $10 sign-up credit pays for priced models first, and once it is gone the models that bill $0 keep their daily requests. A paid subscription, a coupon or the owner raising your account is the only way past the daily number.

StepAudio 3 Chat Preview is developed by StepFun. Model names and trademarks belong to their owners. One AI API Key is an independent API gateway and is not affiliated with, endorsed by or sponsored by StepFun.