Name: BiRefNet API: Background Removal and Alpha Matting
Brand: magicapi
SKU: api-magicapi-background-removal-api-sprited-birefnet
Availability: InStock
Author: API Market

Shashank Agarwal

# ✂️ Background Removal API (Sprited BiRefNet)

## Overview
This listing runs BiRefNet background removal, published by Sprited. Its developer describes it as complete BiRefNet background removal with all 10 official variants plus the ToonOut anime model, and cutout or mask output.

Send an `image` and pick a `variant`. Each request returns the URL of one image: either a cutout with a transparent background (`cutout`, default) or the alpha matte (`mask`). Animated GIF and WebP inputs are supported and come back as an animated WebP with transparency.

## Features
- **11 variants**: `general` (default, all-purpose), `general-hr`, `portrait`, `matting`, `matting-hr`, `dynamic`, `dynamic-matting`, `lite`, `lite-2k`, `lite-matting` and `toonout` (anime and stylized images).
- **Cutout or mask**: `cutout` returns an RGBA image with the background removed; `mask` returns the single-channel alpha matte.
- **Animated input**: animated GIF and WebP are supported and returned as an animated WebP with transparency.
- **Edge controls**: `mask_blur` (0 to 64) softens edges, `mask_offset` (-64 to 64) grows or shrinks the matte, and `refine_fg` removes background color bleed on soft edges.
- **Resolution**: `resolution` 0 (default) uses the variant's native size (1024, or 2048 for HR and 2K variants); set up to 2048 to override.
- **Precision**: `fp32` (default) or `fp16`, which is somewhat faster and uses less memory with negligible quality difference.

## Use Cases
1. **Product photos**: cut products out for catalog and marketplace images.
2. **Portraits and profile pictures**: isolate people with the `portrait` or `matting` variants, as in the example.
3. **Anime and illustrations**: remove backgrounds from stylized art with `toonout`.
4. **Compositing masks**: get the alpha matte with `output_format` `mask` for use in your own editing pipeline.

## Visual Examples
### Example Input
![Input image](https://blog.api.market/wp-content/uploads/2026/10/birefnet-input-api-market.png)

Settings: `variant` `portrait`, `output_format` `cutout`, `resolution` `0`, `mask_blur` `0`, `mask_offset` `0`, `refine_fg` `false`.

### Example Output
![BiRefNet output: the subject cut out with a transparent background](https://blog.api.market/wp-content/uploads/2026/10/birefnet-output-t041e8qe-api-market.png)

## Input Parameters
| Field | Type | Required | Default | Allowed values | Description |
| --- | --- | --- | --- | --- | --- |
| `image` | string (URL) | Yes | none |  | Input image URL. Animated GIF and WebP are supported (returned as an animated WebP with transparency) |
| `variant` | string | No | `general` | `general`, `general-hr`, `portrait`, `matting`, `matting-hr`, `dynamic`, `dynamic-matting`, `lite`, `lite-2k`, `lite-matting`, `toonout` | Which BiRefNet model to use. `general` is the all-purpose default; `toonout` is the anime/stylized fine-tune; the rest are specialized BiRefNet models |
| `resolution` | integer | No | `0` | 0 to 2048 | Inference resolution (square). 0 uses the variant's native resolution (1024, or 2048 for HR/2K variants) |
| `output_format` | string | No | `cutout` | `cutout`, `mask` | `cutout` returns an RGBA image with the background removed; `mask` returns the raw single-channel alpha matte |
| `mask_blur` | integer | No | `0` | 0 to 64 | Gaussian blur radius applied to the matte (softer edges) |
| `mask_offset` | integer | No | `0` | -64 to 64 | Grow (+) or shrink (-) the matte by this many pixels |
| `refine_fg` | boolean | No | `false` |  | Refine foreground colors to remove background bleed on soft edges. Ignored for `mask` output |
| `precision` | string | No | `fp32` | `fp16`, `fp32` | GPU inference precision. `fp32` is full precision; `fp16` is somewhat faster and uses less memory, with negligible quality difference |

## Pricing
- **Pay As You Go (PAYG) pricing**: you only pay for what you use.
- **Price**: $0.0022 per API unit.
- **1 API unit = 1 request with up to 2 seconds of processing.** A request that takes longer uses one unit per started block of 2 seconds (for example, 5 seconds of processing uses 3 units, $0.0066).
- HR and 2K variants, larger `resolution` values and animated inputs take longer and can use more units.
- **Example cost**: the example request (`portrait` variant) took 10.6 seconds of processing, which is 6 units (6 x $0.0022) = **$0.0132**.
- **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/background-removal-api-sprited-birefnet`

### 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/background-removal-api-sprited-birefnet/predictions" \
  -H "Content-Type: application/json" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY" \
  -d '{
    "version": "21f2c4a9159af128ab9b9126401eebe7f8c5310841ed628b74a4c462df00da67",
    "input": {
      "image": "https://blog.api.market/wp-content/uploads/2026/10/birefnet-input-api-market.png",
      "variant": "portrait",
      "mask_blur": 0,
      "refine_fg": false,
      "resolution": 0,
      "mask_offset": 0,
      "output_format": "cutout"
    }
  }'
```

Response (201 Created):
```json
{
  "id": "t041e8qer9rmy0d1d1a9pb57km",
  "version": "21f2c4a9159af128ab9b9126401eebe7f8c5310841ed628b74a4c462df00da67",
  "status": "starting",
  "created_at": "2026-10-23T10:35:59.183Z"
}
```

#### Check Prediction Status
```bash
curl -X GET "https://prod.api.market/api/v1/magicapi/background-removal-api-sprited-birefnet/predictions/{id}" \
  -H "x-api-market-key: YOUR_API_MARKET_KEY"
```

Response when the prediction has finished (200 OK):
```json
{
  "id": "t041e8qer9rmy0d1d1a9pb57km",
  "status": "succeeded",
  "output": "https://blog.api.market/wp-content/uploads/2026/10/birefnet-output-t041e8qe-api-market.png",
  "error": null,
  "created_at": "2026-10-23T10:35:59.183Z",
  "started_at": "2026-10-23T10:35:59.683Z",
  "completed_at": "2026-10-23T10:36:09.792Z"
}
```

`output` is a single URL string pointing to the result image (a transparent cutout, or the mask when `output_format` is `mask`).

### 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 missing `image`, a `variant` that is not in the list, or a `mask_offset` outside -64 to 64.
- **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/background-removal-api-sprited-birefnet";

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: "21f2c4a9159af128ab9b9126401eebe7f8c5310841ed628b74a4c462df00da67", 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({
  "image": "https://blog.api.market/wp-content/uploads/2026/10/birefnet-input-api-market.png",
  "variant": "portrait",
  "mask_blur": 0,
  "refine_fg": false,
  "resolution": 0,
  "mask_offset": 0,
  "output_format": "cutout"
}).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/background-removal-api-sprited-birefnet"


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": "21f2c4a9159af128ab9b9126401eebe7f8c5310841ed628b74a4c462df00da67", "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")


output = create_and_wait_for_prediction({
    "image": "https://blog.api.market/wp-content/uploads/2026/10/birefnet-input-api-market.png",
    "variant": "portrait",
    "mask_blur": 0,
    "refine_fg": False,
    "resolution": 0,
    "mask_offset": 0,
    "output_format": "cutout"
})
print(output)
```

## FAQ
- **Which variant should I use?**
  - Start with `general`. Use `portrait` or the `matting` variants for people and fine edges such as hair, `toonout` for anime and stylized art, the `-hr` and `2k` variants for large images, and the `lite` variants for speed.
- **Can I get just the mask?**
  - Yes. Set `output_format` to `mask` to get the single-channel alpha matte instead of the cutout.
- **Does it work on animated images?**
  - Yes, for animated GIF and WebP. The result is an animated WebP with transparency. Video files are not supported.
- **How do I soften or tighten the edges?**
  - Raise `mask_blur` for softer edges, use a positive `mask_offset` to grow the matte or a negative one to shrink it, and turn on `refine_fg` to remove background color bleed.
- **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.


Remove backgrounds from photos, portraits, anime art and animated GIFs with BiRefNet, returning a transparent cutout or an alpha mask.