Remove image backgrounds in C#
MultipartFormDataContent is built into .NET's HttpClient, so this works in an ASP.NET Core service, a console tool, or a Unity editor script with no extra packages.
Remove a background
using var client = new HttpClient();
using var content = new MultipartFormDataContent();
content.Add(new StreamContent(File.OpenRead("photo.jpg")), "input", "photo.jpg");
content.Add(new StringContent("png"), "format");
client.DefaultRequestHeaders.Add("X-Api-Key", "your-api-key");
var response = await client.PostAsync("https://api.bgbuster.com/images/remove-background", content);
var json = await response.Content.ReadAsStringAsync();
Console.WriteLine(json);The request is a multipart POST to https://api.bgbuster.com/images/remove-background, authenticated with your API key in the X-Api-Key header. Pass the image as a file (input) or as a public URL string.
By default the response is JSON with a temporary download url. That URL stays valid for 24 hours — download and store the image yourself if you need it longer.
Need more than a plain removal? POST /images/edit takes the same kind of request and chains background removal together with resize, rotate, flip, blur, brightness/contrast/saturation, and trim — in whatever order you list them.
| Field | Type | Required | Description |
|---|---|---|---|
| input | File or string | Yes | Image file or a public URL to fetch it from. |
| output | "url" or "raw" | No | Return a temporary download URL, or the transformed image bytes directly. Defaults to "url". |
| format | "png" or "webp" | No | Output image format. Defaults to "png". |
| trim | boolean | No | Trim empty transparent space around the result. |
Default (output=url)
{
"id": "image-id",
"url": "https://..."
}With output=raw, save the image bytes directly instead of following a URL
using var client = new HttpClient();
using var content = new MultipartFormDataContent();
content.Add(new StreamContent(File.OpenRead("photo.jpg")), "input", "photo.jpg");
content.Add(new StringContent("png"), "format");
content.Add(new StringContent("raw"), "output");
client.DefaultRequestHeaders.Add("X-Api-Key", "your-api-key");
var response = await client.PostAsync("https://api.bgbuster.com/images/remove-background", content);
var bytes = await response.Content.ReadAsByteArrayAsync();
await File.WriteAllBytesAsync("result.png", bytes);| Status | Code | Meaning |
|---|---|---|
| 400 | IMAGE_TOO_LARGE | The input image exceeds the size limit. |
| 400 | IMAGE_DECODE_ERROR | The input file couldn't be decoded as an image. |
| 400 | INVALID_IMAGE_URL | The URL passed as input didn't return image content. |
| 400 | UPSTREAM_ERROR | The input URL couldn't be fetched. |
| 401 | UNAUTHORIZED | The API key is missing or invalid. |
| 402 | INSUFFICIENT_BALANCE | Your account is out of credits. |
| 403 | IMAGE_FORBIDDEN | The source CDN blocked the request for the input URL. |
| 429 | TOO_MANY_REQUESTS | Rate limit exceeded — retry after a short delay. |
| 500 | IMAGE_TRANSFORMATION_ERROR | The background removal step failed unexpectedly. |
- 1
Sign up with an email or a social login — no credit card required.
- 2
Buy a credit pack. Credits never expire, and you'll need a balance before the API accepts requests.
- 3
From the dashboard, go to API Keys and click Create API key.
- 4
Authenticate your requests
Send the key in the X-Api-Key header on every request to api.bgbuster.com.