TencentText Generation/v1/ai/chat

Hy4 preview API

Access Hy4 preview through one API key. Tencent Hunyuan 4 Preview Coding Agent MoE.

Hy4 preview is a mixture-of-experts model from Tencent with 49B active parameters out of 770B total, designed for coding agents, complex tool-use workflows and productivity tasks. Hy4 preview is a large, mid-priced model for coding agents and tool-heavy workflows; as a preview, expect it to change before a stable release.

Full Docs Get API Key

Takes 30 seconds.

Hy4 preview API pricing

Pay per request from your YepAPI balance — no subscription, no monthly minimum. Prices updated September 27, 2026.

Token type	Price
Input	$1.23 / 1M tokens
Output	$3.69 / 1M tokens
Context window	1.0M tokens

What it costs	Per job	Per 1,000
Chat reply1K input + 500 output tokens	$0.0031	$3.08
RAG answer8K input + 800 output tokens	$0.013	$12.79
Agent step with tools30K input + 2K output tokens	$0.044	$44.28
Long document summary100K input + 2K output tokens	$0.13	$130.38

4,900+

Developers

2.3M+

API calls served

184

Endpoints

$0.01

Per call

Yep, that's it.

Try it live

Send a message and see Hy4 preview respond in real time.

POST/v1/ai/chattencent/hy4-preview

Message *

Max Tokens

Maximum tokens in the response.

Stream

Real-time tokens

Hit "Send Request" to see the response

Hy4 preview specs

Provider	Tencent
Model ID	tencent/hy4-preview
Endpoint	/v1/ai/chat
Type	Text Generation
Context window	1.05M tokens
Max output	64K tokens
Reasoning	No
OpenAI-compatible	Yes — /v1/ai/chat/completions

How to get a Hy4 preview API key

1
Create an account
Sign up at yepapi.com with Google or email. It takes about 30 seconds.
2
Create an API key
Open the dashboard, go to API Keys and create a key. Copy it — it starts with yep_sk_.
3
Call Hy4 preview
Send a request to /v1/ai/chat with the x-api-key header and model "tencent/hy4-preview".
4
Pay as you go
Usage is billed per request from your balance. Top up any amount; there is no subscription.

Strengths

✓

770B MoE, 49B active

A large mixture-of-experts model tuned for coding and tool use.

✓

Complex tool workflows

Designed for agents that chain many tool calls.

✓

1M context, 64K output

Handles up to 1,048,576 input tokens and returns up to 64,000 output tokens per call.

✓

Preview release

Behaviour may change before Tencent's stable Hy4.

Quick start

Copy this snippet and start making calls with Hy4 preview.

const res = await fetch('https://api.yepapi.com/v1/ai/chat', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "model": "tencent/hy4-preview",
    "messages": [
      {
        "role": "user",
        "content": "Explain API gateways in 2 sentences."
      }
    ],
    "maxTokens": 256
  }),
});
const { data } = await res.json();
console.log(data.message.content);

Hy4 preview vs similar models

Every model below runs on the same API key — switch by changing the model ID.

Model	Provider	Price	Context
Hy4 preview	Tencent	$1.23 in / $3.69 out per 1M	1.0M
Nemotron 3 Super	NVIDIA	$0 in / $0 out per 1M	262K
Qwen3.7 Flash	Qwen	$0.04 in / $0.19 out per 1M	1M
Solar Mini 4	Upstage	$0.07 in / $0.30 out per 1M	524K
Nemotron 3.5 Lightning	NVIDIA	$0.10 in / $0.30 out per 1M	262K
DeepSeek V4 Flash	DeepSeek	$0.13 in / $0.27 out per 1M	1.0M
Qwen 3.5 Flash	Qwen	$0.10 in / $0.38 out per 1M	1M
Seed 1.6 Flash	ByteDance	$0.11 in / $0.44 out per 1M	262K

Why use Hy4 preview through YepAPI?

✓One API key for all models — no separate accounts

✓OpenAI SDK compatible — just change the base URL

✓No monthly minimums — pay per token

✓Switch models with one line of code

✓Full provider passthrough — citations, search results, and all extras included

✓Streaming and non-streaming support on every model

✓Works with Cursor, Claude, LangChain, and any LLM tool

✓Unified billing across all providers

Hy4 preview API — pricing, context window & access

Hy4 preview is a mixture-of-experts model from Tencent with 49B active parameters out of 770B total, designed for coding agents, complex tool-use workflows and productivity tasks. It pairs a 1,048,576-token context window with up to 64,000 output tokens per response, at $1.23 per 1M input and $3.69 per 1M output tokens through YepAPI.

Through YepAPI you call Hy4 preview on an OpenAI-compatible endpoint with a single key — the same key that reaches GPT-6, Claude, Gemini, Grok and the SEO, SERP and scraping APIs. Input: text.

What is Hy4 preview?

Hy4 preview is a mixture-of-experts model from Tencent with 49B active parameters out of 770B total, designed for coding agents, complex tool-use workflows and productivity tasks. It offers a 1,048,576-token context window and up to 64,000 output tokens at $1.23 / $3.69 per 1M tokens. It accepts text as input, handles up to 1,048,576 tokens of context and returns up to 64,000 output tokens per call.

Build with Hy4 preview via YepAPI

YepAPI serves Hy4 preview on the OpenAI-compatible /v1/ai/chat endpoint. Point your base URL at YepAPI, add your key, and set the model string to hy4-preview (or the full tencent/hy4-preview). Function calling, structured outputs and reasoning settings pass straight through, and switching to any other model on the platform is a one-string change per request.

Hy4 preview API pricing — $1.23 / 1M input, $3.69 / 1M output

Hy4 preview costs $1.23 per 1M input tokens and $3.69 per 1M output tokens through YepAPI, pay per token with no minimums. Failed calls are never charged, and every request is itemised in your dashboard API Logs so you can see exactly what a 64,000-token response cost.

Hy4 preview use cases

Hy4 preview is a large, mid-priced model for coding agents and tool-heavy workflows; as a preview, expect it to change before a stable release.

Start generating in 30 seconds

Pay per call, no subscriptions.

Get API Key

What developers say

“Switched from SerpAPI and cut our SERP costs by 80%. Same data quality, way simpler billing.”
Marcus T.
SEO Platform Founder

“One API key for AI models, SERP data, and web scraping. Saved us from managing 4 separate providers.”
Priya S.
Full-Stack Developer

“The $5 free credit let us prototype our entire rank tracking feature before committing. No other API does that.”
Jake R.
Indie Hacker

Frequently asked questions

Hy4 preview costs $1.23 per 1M input tokens and $3.69 per 1M output tokens through YepAPI, billed per request with no monthly fee. For example, a chat reply (1K input + 500 output tokens) costs about $0.0031.

Sign up at yepapi.com (Google or email, about 30 seconds), open the dashboard and create an API key. The same key works for Hy4 preview and every other model — no separate Tencent account or waitlist.

Use "tencent/hy4-preview" as the model on /v1/ai/chat. The short alias "hy4-preview" also works.

Yes. Point the OpenAI SDK at https://api.yepapi.com/v1/ai with your YepAPI key and set model to "tencent/hy4-preview". Streaming works the same way, so existing OpenAI code only needs the base URL and key changed.

Hy4 preview supports a 1.0M token context window with up to 64K output tokens per request.