Name: SDXL ControlNet Canny API: Edge-Guided Image Generation
Brand: magicapi
SKU: api-magicapi-image-to-image-generator-high-resolution-lucataco-sdxl-controlnet
Availability: InStock
Author: API Market

Shashank Agarwal

# ✏️ Canny Edge-Guided Image Generation API (lucataco SDXL ControlNet)

## Overview
SDXL ControlNet (Canny) generates an image with Stable Diffusion XL while following the edges of an input image. It is published by lucataco and described by its developer as "SDXL ControlNet - Canny".

Send an `image` and a text `prompt`. The ControlNet uses the Canny edges of the image to guide the layout of the new image, and `condition_scale` sets how strongly. Each request returns the URL of one image.

## Features
- **Edge-guided generation**: keeps the outlines and composition of your `image` while the `prompt` sets content and style.
- **Conditioning strength**: `condition_scale` (0 to 1, default 0.5) controls how closely the result follows the edges.
- **Negative prompt**: `negative_prompt` (default `low quality, bad quality, sketches`) lists what to avoid.
- **Inference steps**: `num_inference_steps` from 1 to 500 (default 50).
- **Seed**: set `seed` to reproduce a result; 0 (default) picks a random seed.

## Use Cases
1. **Concept art from sketches or line art**: turn outlines into finished scenes.
2. **Restyling a photo while keeping its layout**: same structure, new subject matter or style.
3. **Architecture and product visuals**: keep shapes and perspective from a reference while changing materials and lighting.
4. **Consistent compositions**: generate several styles of one layout by changing only the prompt.

## Visual Examples
### Example Input
Prompt: "aerial view, a futuristic research complex in a bright foggy jungle, hard lighting"

Input image (`image`):

![SDXL ControlNet example input image](https://blog.api.market/wp-content/uploads/2026/10/sdxl-controlnet-input-api-market.png)

Settings: `condition_scale` 0.5, `num_inference_steps` 50, `seed` 18457, `negative_prompt` `low quality, bad quality, sketches`.

### Example Output
![SDXL ControlNet output: aerial view of a futuristic research complex in a foggy jungle following the edges of the input image](https://blog.api.market/wp-content/uploads/2026/10/sdxl-controlnet-output-myr6vken-api-market.jpg)

## Input Parameters
| Field | Type | Required | Default | Allowed values | Description |
| --- | --- | --- | --- | --- | --- |
| `image` | string (URL) | No | none |  | Input image URL (jpeg, png, gif or webp). Its Canny edges guide the generated image |
| `prompt` | string | No | `aerial view, a futuristic research complex in a bright foggy jungle, hard lighting` |  | Input prompt |
| `negative_prompt` | string | No | `low quality, bad quality, sketches` |  | Input negative prompt |
| `num_inference_steps` | integer | No | `50` | 1 to 500 | Number of denoising steps |
| `condition_scale` | number | No | `0.5` | 0 to 1 | ControlNet conditioning scale for generalization |
| `seed` | integer | No | `0` |  | Random seed. Set to 0 to randomize the seed |

## Pricing
- **Pay As You Go (PAYG) pricing**: you only pay for what you use.
- **Price**: $0.016 per API unit.
- **1 API unit = 1 request with up to 14 seconds of processing.** A request that runs longer bills one more unit for each started 14-second block (for example, 20 seconds of processing is 2 units, $0.032).
- More `num_inference_steps` take longer and can use more units.
- **Example cost**: the example request below (50 steps) took 9.4 seconds of processing, which is 1 unit: $0.016.
- **Failed or cancelled predictions are not billed.**
- **GET requests to check prediction status** are free and don't count toward API unit usage.
- **No monthly subscription fee.**

## API Documentation

### Base URL
All API requests go to: `https://prod.api.market/api/v1/magicapi/image-to-image-generator-high-resolution-lucataco-sdxl-controlnet`

### Authentication
Send your api.market API key in the `x-api-market-key` header:
```
x-api-market-key: YOUR_API_MARKET_KEY
```

### Asynchronous Processing
**IMPORTANT**: This API is asynchronous. The flow is:
1. Send a POST request to `/predictions`. A successful request returns **201 Created** with a prediction `id` and a `status` of `starting` or `processing`.
2. Poll GET `/predictions/{id}` with that ID.
3. Keep polling while `status` is `starting` or `processing`.
4. Stop when `status` is `succeeded` (read `output`), `failed` or `canceled` (read `error`).

A polling interval of 1 second and an overall timeout of 600 seconds (10 minutes) work well.

### Endpoints

#### Create a Prediction
```bash
curl -X POST "https://prod.api.market/api/v1/magicapi/image-to-image-generator-high-resolution-lucataco-sdxl-controlnet/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "06d6fae3b75ab68a28cd2900afa6033166910dd09fd9751047043a5bbb4c184b",
    "input": {
      "seed": 18457,
      "image": "https://blog.api.market/wp-content/uploads/2026/10/sdxl-controlnet-input-api-market.png",
      "prompt": "aerial view, a futuristic research complex in a bright foggy jungle, hard lighting",
      "condition_scale": 0.5,
      "negative_prompt": "low quality, bad quality, sketches",
      "num_inference_steps": 50
    }
  }'
```

Response (201 Created):
```json
{
  "id": "myr6vken51rmt0d1cct8yn1258",
  "version": "06d6fae3b75ab68a28cd2900afa6033166910dd09fd9751047043a5bbb4c184b",
  "status": "starting",
  "created_at": "2026-10-22T10:42:49.425Z"
}
```

#### Check Prediction Status
```bash
curl -X GET "https://prod.api.market/api/v1/magicapi/image-to-image-generator-high-resolution-lucataco-sdxl-controlnet/predictions/{id}" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

Response when the prediction has finished (200 OK):
```json
{
  "id": "myr6vken51rmt0d1cct8yn1258",
  "status": "succeeded",
  "output": "https://blog.api.market/wp-content/uploads/2026/10/sdxl-controlnet-output-myr6vken-api-market.jpg",
  "error": null,
  "created_at": "2026-10-22T10:42:49.425Z",
  "started_at": "2026-10-22T10:42:57.374Z",
  "completed_at": "2026-10-22T10:43:06.768Z"
}
```

`output` is a single URL string pointing to the generated image.

### Status Codes
- **201 Created**: prediction created (POST `/predictions`). This is the normal success response.
- **200 OK**: prediction details returned (GET `/predictions/{id}`).
- **400 Bad Request**: invalid input, for example a `condition_scale` above 1 or `num_inference_steps` above 500.
- **401 Unauthorized**: missing or invalid API key.
- **404 Not Found**: no prediction with that ID.
- **429 Too Many Requests**: rate limit exceeded.
- **500 Internal Server Error** or **503 Service Unavailable**: temporary server problem; retry later.

## Rate Limits
All plans allow 10 requests per second. Requests above that return `429 Too Many Requests`; back off before retrying and honour any `Retry-After` header. Polling a prediction with GET is free but still counts toward the per-second limit, so poll every 1 to 5 seconds rather than in a tight loop.

## Error Handling
- Check the HTTP status code of every request and read the response body for the error message.
- A prediction can also end with `status` set to `failed`; the `error` field then explains why. Failed predictions are not billed.
- Retry 429, 500 and 503 responses with exponential backoff. Fix the input before retrying a 400.

## Implementation Guide
### Example Code

#### JavaScript
```javascript
const apiKey = "YOUR_API_MARKET_KEY";
const baseUrl = "https://prod.api.market/api/v1/magicapi/image-to-image-generator-high-resolution-lucataco-sdxl-controlnet";

async function createAndWaitForPrediction(input) {
  const response = await fetch(`${baseUrl}/predictions`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-market-key": apiKey
    },
    body: JSON.stringify({ version: "06d6fae3b75ab68a28cd2900afa6033166910dd09fd9751047043a5bbb4c184b", input })
  });

  if (response.status !== 201) {
    throw new Error(`API error: ${response.status} ${await response.text()}`);
  }

  const prediction = await response.json();
  return pollForResults(prediction.id);
}

const delay = (ms) => new Promise((resolve) => setTimeout(resolve, ms));

async function pollForResults(predictionId) {
  const maxTimeout = 600000;
  const pollInterval = 1000;
  const startTime = Date.now();

  while (Date.now() - startTime < maxTimeout) {
    const response = await fetch(`${baseUrl}/predictions/${predictionId}`, {
      headers: { "x-api-market-key": apiKey }
    });

    if (!response.ok) {
      throw new Error(`API error: ${response.status} ${await response.text()}`);
    }

    const prediction = await response.json();

    if (prediction.status === "succeeded") {
      return prediction.output;
    }

    if (prediction.status === "failed" || prediction.status === "canceled") {
      throw new Error(`Prediction ${prediction.status}: ${prediction.error || "Unknown error"}`);
    }

    await delay(pollInterval);
  }

  throw new Error("Prediction timed out after 10 minutes");
}

createAndWaitForPrediction({
  seed: 18457,
  image: "https://blog.api.market/wp-content/uploads/2026/10/sdxl-controlnet-input-api-market.png",
  prompt: "aerial view, a futuristic research complex in a bright foggy jungle, hard lighting",
  condition_scale: 0.5,
  negative_prompt: "low quality, bad quality, sketches",
  num_inference_steps: 50
}).then((output) => console.log(output));
```

#### Python
```python
import time
import requests

API_KEY = "YOUR_API_MARKET_KEY"
BASE_URL = "https://prod.api.market/api/v1/magicapi/image-to-image-generator-high-resolution-lucataco-sdxl-controlnet"


def create_and_wait_for_prediction(input_data):
    headers = {"Content-Type": "application/json", "x-api-market-key": API_KEY}
    response = requests.post(
        f"{BASE_URL}/predictions",
        headers=headers,
        json={"version": "06d6fae3b75ab68a28cd2900afa6033166910dd09fd9751047043a5bbb4c184b", "input": input_data},
    )

    if response.status_code != 201:
        raise Exception(f"API error: {response.status_code} {response.text}")

    return poll_for_results(response.json()["id"])


def poll_for_results(prediction_id):
    max_timeout = 600
    poll_interval = 1
    headers = {"x-api-market-key": API_KEY}
    start_time = time.time()

    while time.time() - start_time < max_timeout:
        response = requests.get(f"{BASE_URL}/predictions/{prediction_id}", headers=headers)

        if response.status_code != 200:
            raise Exception(f"API error: {response.status_code} {response.text}")

        prediction = response.json()

        if prediction["status"] == "succeeded":
            return prediction["output"]

        if prediction["status"] in ("failed", "canceled"):
            raise Exception(f"Prediction {prediction['status']}: {prediction.get('error') or 'Unknown error'}")

        time.sleep(poll_interval)

    raise Exception("Prediction timed out after 10 minutes")


print(create_and_wait_for_prediction({
    "seed": 18457,
    "image": "https://blog.api.market/wp-content/uploads/2026/10/sdxl-controlnet-input-api-market.png",
    "prompt": "aerial view, a futuristic research complex in a bright foggy jungle, hard lighting",
    "condition_scale": 0.5,
    "negative_prompt": "low quality, bad quality, sketches",
    "num_inference_steps": 50,
}))
```

## FAQ
- **What does the input image do?**
  - The ControlNet extracts the Canny edges of `image` and uses them to guide the layout of the generated image. The prompt decides what fills those outlines.
- **How closely does the result follow my image?**
  - `condition_scale` sets it: higher values (up to 1) follow the edges more strictly, lower values give the prompt more freedom. The default is 0.5.
- **How do I get the same image again?**
  - Send the same inputs with a fixed non-zero `seed`. A `seed` of 0 (the default) picks a random seed each time.
- **How much does a request cost?**
  - $0.016 for up to 14 seconds of processing, plus one unit per further started 14-second block. The example with 50 steps took 9.4 seconds and cost $0.016.
- **Is the 201 response from POST an error?**
  - No. 201 Created means the prediction was accepted. Use the returned `id` to poll GET `/predictions/{id}` until `status` is `succeeded`, `failed` or `canceled`.
- **What if my prediction fails?**
  - Failed predictions are not billed. Read the `error` field, adjust the input and try again.

## Contact Us
If you have any questions, reach out to us through the chat on the bottom right of the page. You can also email our support team at hello@magicapi.com.


Turn sketches, line art and photos into new images with SDXL ControlNet Canny: the result keeps your image's edges while the prompt sets the content.