Name: Image Variation API (FLUX.1 Redux [schnell])
Brand: magicapi
SKU: api-magicapi-fast-image-variation-api-black-forest-labs-flux-redux-schnell
Availability: InStock
Author: API Market

Shashank Agarwal

# ⚡ Fast Image Variation API (FLUX.1 Redux [schnell])

## Overview
FLUX.1 Redux [schnell] from Black Forest Labs creates variations of an image you provide. There is no text prompt: the input image in `redux_image` takes the place of the prompt, and the model generates new images based on it. It is a fast, efficient model meant for rapid iteration and experimentation.

Each request returns 1 to 4 images (set with `num_outputs`) as an array of URLs.

## Features
- **Image variations**: pass one image in `redux_image` and get new images conditioned on it.
- **Several outputs per request**: `num_outputs` from 1 to 4 (default 1).
- **Aspect ratio**: `1:1` (default), `16:9`, `21:9`, `3:2`, `2:3`, `4:5`, `5:4`, `3:4`, `4:3`, `9:16` or `9:21`.
- **Output size**: `megapixels` of `"1"` (default) or `"0.25"` for smaller images.
- **Steps**: `num_inference_steps` from 1 to 4 (default 4). Fewer steps are faster but lower quality.
- **Output control**: `output_format` of `webp` (default), `jpg` or `png`, and `output_quality` from 0 to 100 (default 80, not used for png).
- **Reproducible results**: set `seed` to repeat a generation.
- **Safety checker**: on by default; `disable_safety_checker` turns it off.

## Use Cases
1. **Exploring alternatives**: get several takes on a photo or illustration before choosing a direction.
2. **Reformatting a look**: produce variations of an image in another aspect ratio, for example `16:9` for a banner or `9:16` for a story.
3. **Ad and social testing**: create a few versions of one visual to compare in A/B tests.
4. **Fast drafts**: use `megapixels` `"0.25"` and fewer steps for quick previews, then generate the final at full size.

## Visual Examples

The example request sent only `redux_image`; every other field used its default (one `1:1` image, 1 megapixel, webp). The input image shows a woman in a yellow hooded raincoat on a wet city street at night under a neon sign.

### Input image
![Input image: a woman in a yellow hooded raincoat on a wet street at night under a neon sign](https://blog.api.market/wp-content/uploads/2026/09/kling-v2-1-input-api-market.webp)

### Output image
![Variation of the input image generated by FLUX.1 Redux schnell](https://blog.api.market/wp-content/uploads/2026/10/flux-redux-schnell-output-api-market.webp)

## Pricing
- Pay As You Go (PAYG) pricing: you only pay for what you use.
- Price: $0.0038 per API unit.
- 1 API unit = 1 output image. A request is billed for every image it returns, set by `num_outputs`:
  - `num_outputs` 1 (default): 1 unit = $0.0038
  - `num_outputs` 2: 2 units = $0.0076
  - `num_outputs` 3: 3 units = $0.0114
  - `num_outputs` 4: 4 units = $0.0152
- Failed or cancelled predictions are not billed.
- GET requests to check prediction status (GET /api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell/predictions/{id}) are free and don't count toward API unit usage.
- No monthly subscription fee.

## API Documentation

### Base URL
All API requests should be made to: `https://prod.api.market/api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell`

### Authentication
Include your api.market API key in the `x-api-market-key` header of every request:
```
x-api-market-key: YOUR_API_MARKET_KEY
```

### Asynchronous Processing
This API is asynchronous:

1. Send a POST request to `/predictions`. A successful request returns **201 Created** with a prediction `id` and a `status` of `starting` or `processing`. 201 means the prediction was accepted; it is not an error.
2. Poll GET `/predictions/{id}` (about once per second) while `status` is `starting` or `processing`.
3. Stop when `status` is `succeeded` (read the result from `output`), `failed` (see `error`) or `canceled`.

### Endpoints

#### Create a Prediction
```bash
curl -X POST "https://prod.api.market/api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "8a9ff6ce228b950c7079005fd0804f54c74c0113cda3f3c07eff10ab943f32a1",
    "input": {
      "redux_image": "https://blog.api.market/wp-content/uploads/2026/09/kling-v2-1-input-api-market.webp"
    }
  }'
```

Response (201 Created):
```json
{
  "id": "ufawqhfynnddngldkgtslldrkq",
  "version": "8a9ff6ce228b950c7079005fd0804f54c74c0113cda3f3c07eff10ab943f32a1",
  "status": "starting",
  "created_at": "2026-10-13T10:33:40.967Z"
}
```

#### Check Prediction Status
```bash
curl -X GET "https://prod.api.market/api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell/predictions/{id}" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

Response when the prediction has finished (200 OK):
```json
{
  "id": "ufawqhfynnddngldkgtslldrkq",
  "status": "succeeded",
  "output": [
    "https://blog.api.market/wp-content/uploads/2026/10/flux-redux-schnell-output-api-market.webp"
  ],
  "error": null,
  "created_at": "2026-10-13T10:33:40.967Z",
  "started_at": "2026-10-13T10:33:41.512Z",
  "completed_at": "2026-10-13T10:34:02.104Z"
}
```

### Input Parameters

| Name | Type | Default | Allowed values | Required | Description |
|------|------|---------|----------------|----------|-------------|
| `redux_image` | string (URI) |  | Image URL | Yes | Input image to condition your output on. This replaces the prompt for FLUX.1 Redux models. |
| `aspect_ratio` | string | `1:1` | `1:1`, `16:9`, `21:9`, `3:2`, `2:3`, `4:5`, `5:4`, `3:4`, `4:3`, `9:16`, `9:21` | No | Aspect ratio for the generated image. |
| `num_outputs` | integer | `1` | 1 to 4 | No | Number of outputs to generate. |
| `num_inference_steps` | integer | `4` | 1 to 4 | No | Number of denoising steps. 4 is recommended; fewer steps produce lower quality outputs, faster. |
| `seed` | integer |  | Any integer | No | Random seed. Set for reproducible generation. |
| `output_format` | string | `webp` | `webp`, `jpg`, `png` | No | Format of the output images. |
| `output_quality` | integer | `80` | 0 to 100 | No | Quality when saving the output images. 100 is best quality, 0 is lowest. Not relevant for png outputs. |
| `disable_safety_checker` | boolean | `false` | `true`, `false` | No | Disable the safety checker for generated images. |
| `megapixels` | string | `"1"` | `"1"`, `"0.25"` | No | Approximate number of megapixels for the generated image. Sent as a string. |

### Output
`output` is an array of URLs, one per generated image (up to 4).

### Status Codes

| Status code | Meaning | What to do |
|-------------|---------|------------|
| 200 OK | GET returned the prediction | Check `status`; keep polling while it is `starting` or `processing`. |
| 201 Created | POST accepted, prediction created | Success. Poll GET `/predictions/{id}` with the returned `id`. |
| 400 Bad Request | Invalid input (for example a missing `redux_image`, an unreachable image URL or `num_outputs` above 4) | Fix the request body and send it again. |
| 401 Unauthorized | Missing or invalid API key | Send a valid key in the `x-api-market-key` header. |
| 403 Forbidden | The key is not allowed to use this API | Check your subscription for this API. |
| 404 Not Found | Unknown prediction ID or wrong URL | Check the base URL and the prediction `id`. |
| 429 Too Many Requests | Rate limit exceeded | Wait and retry with backoff. |
| 500 Internal Server Error | Server-side error | Retry; if it keeps happening, contact us. |
| 503 Service Unavailable | Service temporarily unavailable | Retry after a short wait. |

### 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.

## Implementation Guide

### Example Code

#### JavaScript
```javascript
const apiKey = "YOUR_API_MARKET_KEY";
const baseUrl = "https://prod.api.market/api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell";

async function createAndWaitForPrediction(inputData) {
  // Step 1: create the prediction (201 Created on success)
  const response = await fetch(`${baseUrl}/predictions`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "x-api-market-key": apiKey
    },
    body: JSON.stringify({ version: "8a9ff6ce228b950c7079005fd0804f54c74c0113cda3f3c07eff10ab943f32a1", input: inputData })
  });

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

  const prediction = await response.json();

  // Step 2: poll for the result
  return await pollForResults(prediction.id);
}

function delay(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

async function pollForResults(predictionId) {
  const MAX_TIMEOUT = 600000; // 600 seconds (10 minutes)
  const POLL_INTERVAL = 1000; // 1 second between checks
  const startTime = Date.now();

  while (Date.now() - startTime < MAX_TIMEOUT) {
    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(POLL_INTERVAL);
  }

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

createAndWaitForPrediction({
  "redux_image": "https://blog.api.market/wp-content/uploads/2026/09/kling-v2-1-input-api-market.webp"
})
  .then(output => console.log(output))
  .catch(error => console.error(error));
```

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

API_KEY = "YOUR_API_MARKET_KEY"
BASE_URL = "https://prod.api.market/api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell"

def create_and_wait_for_prediction(input_data):
    # Step 1: create the prediction (201 Created on success)
    response = requests.post(
        f"{BASE_URL}/predictions",
        headers={"Content-Type": "application/json", "x-api-market-key": API_KEY},
        json={"version": "8a9ff6ce228b950c7079005fd0804f54c74c0113cda3f3c07eff10ab943f32a1", "input": input_data},
    )
    if response.status_code not in (200, 201):
        raise Exception(f"API error: {response.status_code} {response.text}")

    # Step 2: poll for the result
    return poll_for_results(response.json()["id"])

def poll_for_results(prediction_id):
    MAX_TIMEOUT = 600  # 600 seconds (10 minutes)
    POLL_INTERVAL = 1  # 1 second between checks
    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({
    "redux_image": "https://blog.api.market/wp-content/uploads/2026/09/kling-v2-1-input-api-market.webp"
}))
```

#### cURL
```bash
# Step 1: create a prediction (returns 201 Created with an id)
curl -X POST "https://prod.api.market/api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "8a9ff6ce228b950c7079005fd0804f54c74c0113cda3f3c07eff10ab943f32a1",
    "input": {
      "redux_image": "https://blog.api.market/wp-content/uploads/2026/09/kling-v2-1-input-api-market.webp"
    }
  }'

# Step 2: check the prediction (replace PREDICTION_ID with the id from step 1)
# Repeat about once per second until status is succeeded, failed or canceled.
curl -X GET "https://prod.api.market/api/v1/magicapi/fast-image-variation-api-black-forest-labs-flux-redux-schnell/predictions/PREDICTION_ID" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

### Performance Optimization
- Keep `num_inference_steps` at 4 for final images; lower it only for quick previews.
- Use `megapixels` `"0.25"` when you only need small previews.
- Ask for several images in one request with `num_outputs` instead of sending several requests (each image is billed the same either way).

## FAQ

**Do I need a text prompt?**
No. This model has no prompt field. The image in `redux_image` replaces the prompt.

**How many images can one request return?**
Up to 4, set with `num_outputs`. Each image is billed at $0.0038.

**Can I control the output size?**
You can choose the aspect ratio with `aspect_ratio` and the approximate size with `megapixels` (`"1"` or `"0.25"`).

**How do I get the same result again?**
Send the same input with the same `seed`.

## Contact Us

If you have any questions or need assistance, you can reach out to us through the embedded chat on the bottom right corner of the page or send an email to hello@magicapi.com.


Create variations of an input image with FLUX.1 Redux [schnell] by Black Forest Labs. No prompt needed, up to 4 images per request, $0.0038 per image.