> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nunchux.ai/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Authenticate every request with your API key in the `X-API-Key` header or `Authorization: Bearer`. Keys start with `sk-nunchux-`.
> Image generation is synchronous: the image is in the response.
> Video generation is asynchronous: submit the job, poll its task until it reaches a terminal status, then download the output promptly, because output URLs expire.

# Performance Tiers

> Balance speed and cost with the performance tiers of the Nunchux Image API.

# Performance Tiers

### Balance speed and cost with performance tiers

## Available Tiers

### Nunchux Optimized models

The Radical Speed tier delivers the lowest latency, while Radical Value gives the lowest cost per image. Both tiers run on Nunchux's proprietary Model Optimizer and Inference Engine. Together they give the best tradeoff between speed, cost, and quality on the market.

These tiers apply to the FLUX, Qwen and HiDream O1 models. Ideogram 4 has three other tiers: Turbo (12 steps), Balanced (20 steps) and Quality (48 steps). The step count selects the tier, and the price is per image. The LTX video models have two other tiers, 720p and 1080p. The output size selects the tier, and the price is per second of video.

### Partner models

Partner models do not use the Nunchux tiers. Each one prices on its own terms, such as output size, resolution, or mode. See the [pricing page](https://nunchux.ai/pricing) for current per-model rates.

## Tier Comparison

| Tier | Speed | Cost | Quality | Use Case |
| - | - | - | - | - |
| `radical_speed` | Fastest | Low | High | Real-time apps, previews |
| `radical_value` | Fast | Lowest | High | High-volume batch, cost-sensitive jobs |

<Tip>
  What tier should I choose?

  Use Radical Speed if the response time is important. Use Radical Value if cost per image is more important across large batches.
</Tip>

## Send a Tier in a Request

Set the `tier` field in your API request:

```bash theme={"system"}
curl -X POST https://api.nunchux.ai/v1/images/generations \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nunchux-qwen-image-2512",
    "tier": "radical_speed",
    "prompt": "a beautiful mountain landscape",
    "width": 1024,
    "height": 1024
  }'
```

## Tier and Model Combinations

Each tier and model combination has a different use. The Qwen model with the Radical Speed tier gives the lowest latency. Use this combination for real-time previews and interactive applications.

```bash theme={"system"}
# Fastest generation: Qwen Image 2512 + radical_speed
curl -X POST https://api.nunchux.ai/v1/images/generations \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nunchux-qwen-image-2512",
    "tier": "radical_speed",
    "prompt": "real-time preview render",
    "width": 1024,
    "height": 1024
  }'
```

A small model such as Klein 4B with the Radical Value tier gives the lowest cost per image. Use this combination for high-volume batch jobs.

```bash theme={"system"}
# Lowest cost: Klein 4B + radical_value
curl -X POST https://api.nunchux.ai/v1/images/generations \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nunchux-flux.2-klein-4b",
    "tier": "radical_value",
    "prompt": "high-volume batch icon design",
    "width": 1024,
    "height": 1024
  }'
```

<Info>
  Workflow Recommendations

  * For development and test, use Radical Speed. It has the lowest latency.
  * For high-volume batch jobs, use Radical Value. It has the lowest cost per image.
  * For production, use Radical Speed if latency is important. Use Radical Value if cost per image is more important.
</Info>

## Error Handling

If you send a tier that a model does not support, the API returns an error.

```json theme={"system"}
{
  "detail": "unknown tier 'turbo'; allowed values: radical_speed, radical_value"
}
```

Check the model's page to make sure that it supports the tier you send. See the [Error Handling](/errors) guide for more information.


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