# Youchuan V8.1 Text-to-Image — Atlas Cloud API

> Youchuan V8.1 generates four images from a text prompt, with optional native 2K HD, a style reference, and aspect-ratio / stylize / chaos / weird controls.

This is the machine-readable API reference for **Youchuan V8.1 Text-to-Image** on Atlas Cloud,
a unified API platform for 400+ AI models across text, image, video, audio and 3D.

- **Model ID**: `youchuan/v8.1/text-to-image`
- **Built by**: MIDJOURNEY
- **Modality**: Image
- **Model page**: https://www.atlascloud.ai/models/youchuan/v8.1/text-to-image
- **API key**: https://www.atlascloud.ai/console/api-keys
- **Docs**: https://www.atlascloud.ai/docs

## Pricing on Atlas Cloud

- $0.086 per image
- Pay-as-you-go. No minimum spend, no subscription required.

> **These are the authoritative Atlas Cloud rates for this model.** Any price that
> appears in the vendor description further down refers to a different platform or
> a different model variant and does not apply here.

## Use this model from an AI agent

Atlas Cloud ships three first-party integration surfaces. All three authenticate
with the same API key via the `ATLASCLOUD_API_KEY` environment variable.

### MCP server

The official MCP server (`atlascloud-mcp`) exposes this model to any
MCP-compatible host — Claude Code, OpenAI Codex, Cursor, Gemini CLI, Goose,
Claude Desktop. One-line install:

```bash
# Claude Code
claude mcp add atlascloud -- npx -y atlascloud-mcp

# OpenAI Codex CLI
codex mcp add atlascloud -- npx -y atlascloud-mcp

# Gemini CLI
gemini mcp add atlascloud -- npx -y atlascloud-mcp

export ATLASCLOUD_API_KEY="your-api-key"
```

Then ask in plain English; the agent calls `atlas_generate_image` with `model: "youchuan/v8.1/text-to-image"`.
The server fetches each model's schema and validates parameters before submitting,
so invalid requests fail fast without spending credits.

MCP docs: https://www.atlascloud.ai/docs/mcp-server

### Agent Skills

`atlas-cloud-skills` is a portable skill package (API reference, code templates in
Python / Node.js / cURL, model IDs with pricing) for Claude Code, Cursor, Codex and
12+ other agents:

```bash
npx skills add AtlasCloudAI/atlas-cloud-skills
export ATLASCLOUD_API_KEY="your-api-key"
```

Skills docs: https://www.atlascloud.ai/docs/skills

### CLI

The `atlas` binary runs Atlas Cloud from a terminal or CI script. Async media jobs
are polled and downloaded automatically (use `--no-download` when a script only
needs the output URLs):

```bash
# Install (Homebrew, npm, or shell installer)
brew install AtlasCloudAI/tap/atlascloud
# npm install -g atlascloud-cli
# curl -fsSL https://raw.githubusercontent.com/AtlasCloudAI/cli/main/install.sh | sh

atlas auth login
atlas generate image youchuan/v8.1/text-to-image -p "Your prompt here"
```

CLI docs: https://www.atlascloud.ai/docs/cli

## HTTP API reference

- **Submit endpoint (POST)**: `https://api.atlascloud.ai/api/v1/model/generateImage` — start an async generation; returns a `prediction_id`
- **Poll endpoint (GET)**: `https://api.atlascloud.ai/api/v1/model/prediction/{prediction_id}` — poll this until the prediction finishes
- **Model ID**: `youchuan/v8.1/text-to-image`


## API Information

This model can be used via our HTTP API or more conveniently via our client libraries.
See the input and output schema below, as well as the usage examples.


### Input Schema

The API accepts the following input parameters:

- **`model`** (`string`, _required_):
  Model name.
  - Default: `"youchuan/v8.1/text-to-image"`

- **`prompt`** (`string`, _required_):
  Natural-language description of the image to generate. Maximum 1024 characters (Youchuan command flags embedded in the prompt are not counted toward the limit). Each task returns 4 images.
  - Default: `"A serene mountain lake at sunrise, photorealistic"`

- **`sref`** (`string`, _optional_):
  Optional URL of a style-reference image. Must be a publicly reachable https image URL.

- **`aspect_ratio`** (`string`, _optional_):
  Aspect ratio of the generated image.
  - Default: `"1:1"`
  - Options: "1:1", "9:16", "16:9", "4:3", "3:4", "2:3", "3:2", "9:21", "21:9"

- **`hd`** (`boolean`, _optional_):
  Enable native 2K HD generation. Costs 1.5x.
  - Default: `false`

- **`stylize`** (`integer`, _optional_):
  Controls how strongly the model's default aesthetic is applied (0-1000).
  - Default: `0`
  - Min: 0
  - Max: 1000

- **`chaos`** (`integer`, _optional_):
  Higher values produce more unusual and varied results (0-100).
  - Default: `0`
  - Min: 0
  - Max: 100

- **`weird`** (`integer`, _optional_):
  Makes results quirky and unconventional (0-3000).
  - Default: `0`
  - Min: 0
  - Max: 3000

- **`quality`** (`number`, _optional_):
  Controls image detail. 4 = higher detail at the same price (slower). v8.1 supports 1 or 4 only.
  - Default: `1`
  - Options: 1, 4

- **`seed`** (`integer`, _optional_):
  Use the same seed and prompt to get reproducible results. -1 = random.
  - Default: `-1`

- **`enable_base64_output`** (`boolean`, _optional_):
  If enabled, the output will be encoded into a BASE64 string instead of a URL.
  - Default: `false`



**Required Parameters Example**:

```json
{
  "model": "youchuan/v8.1/text-to-image",
  "prompt": "A serene mountain lake at sunrise, photorealistic"
}
```


**Full Example**:

```json
{
  "model": "youchuan/v8.1/text-to-image",
  "prompt": "A serene mountain lake at sunrise, photorealistic",
  "sref": "",
  "aspect_ratio": "1:1",
  "hd": false,
  "stylize": 0,
  "chaos": 0,
  "weird": 0,
  "quality": 1,
  "seed": -1,
  "enable_base64_output": false
}
```


### Output Schema

The API returns the following output format:


- **`id`** (`string`, _optional_):
  Unique identifier for the prediction, the ID of the prediction to get.

- **`urls`** (`object`, _optional_):
  Object containing related API endpoints.

- **`model`** (`string`, _optional_):
  Model ID used for the prediction.

- **`status`** (`string`, _optional_):
  Status of the task: created, processing, completed, or failed.

- **`outputs`** (`array[string]`, _optional_):
  Array of URLs to the generated images (empty when status is not completed).

- **`created_at`** (`string`, _optional_):
  ISO timestamp of when the request was created.



**Example Response**:

```json
{
  "id": "",
  "urls": {},
  "model": "",
  "status": "",
  "outputs": [
    ""
  ],
  "created_at": ""
}
```


## Usage Examples

### cURL

```bash
# Step 1: Start generation (async)
curl -X POST "https://api.atlascloud.ai/api/v1/model/generateImage" \
  -H "Authorization: Bearer $ATLASCLOUD_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "youchuan/v8.1/text-to-image",
  "prompt": "A serene mountain lake at sunrise, photorealistic",
  "sref": "",
  "aspect_ratio": "1:1",
  "hd": false,
  "stylize": 0,
  "chaos": 0,
  "weird": 0,
  "quality": 1,
  "seed": -1,
  "enable_base64_output": false
}'

# Response will contain: {"code": 200, "data": {"id": "prediction_id", "status": "processing"}}

# Step 2: Poll for result (replace {prediction_id} with the id returned above)
curl -X GET "https://api.atlascloud.ai/api/v1/model/prediction/{prediction_id}" \
  -H "Authorization: Bearer $ATLASCLOUD_API_KEY"

# Keep polling until status is "completed", "succeeded" or "failed"
# When completed, outputs will contain the generated content URL(s)
```

## Additional Resources

### Documentation

- [Model Playground](https://www.atlascloud.ai/models/youchuan/v8.1/text-to-image)

## About this model

_Vendor-supplied description. Any pricing or endpoint mentioned below refers to_
_other platforms — use the Atlas Cloud values above._

#### 1. Introduction

> **About Youchuan (悠船):** "Youchuan V8.1" is Midjourney's V8.1 model delivered through **Youchuan (悠船)**, Midjourney's officially authorized platform in China — self-branded *"Midjourney 中国实验室" (Midjourney China Lab)* and operated by Xiaochuan Creative (Shanghai) Network Technology Co., Ltd. (小船创意). Youchuan is a **legitimate, licensed distributor of Midjourney's models** (not a third-party clone): it offers the same Midjourney technology, localized for the Chinese market with priority access to new model versions.

**Youchuan V8.1** is the latest iteration of Midjourney's image-synthesis model. This README covers the two core generation endpoints:

- `youchuan/v8.1/text-to-image`
- `youchuan/v8.1/image-to-video`

It belongs to a larger Youchuan V8.1 family on this platform, which also includes `youchuan/v8.1/image-to-image`, `youchuan/v8.1/blend`, `youchuan/v8.1/style-transfer`, and `youchuan/v8.1/remove-background` (each documented separately).

Youchuan V8.1 is designed to produce high-aesthetic, prompt-faithful imagery at native 2K resolution with substantially faster generation than prior versions. It is built by Midjourney, an independent, self-funded San Francisco research lab (~11–50 staff) founded in August 2021 by David Holz, and is positioned as a speed- and quality-focused evolution of the company's image pipeline.

_(Description truncated. Full text on the model page.)_

---

Atlas Cloud — one API for 400+ AI models. Model page: https://www.atlascloud.ai/models/youchuan/v8.1/text-to-image · Docs: https://www.atlascloud.ai/docs