LassoCut background removal API reference

LassoCut is a background removal API compatible with the remove.bg API: the same request shape, the same X-Api-Key header, and the same JSON error format. Point an existing integration at a new base URL and key, or start from the examples below. This page documents every request field, response header, error code and limit.

Moving from remove.bg? See the migration guide.

Basics

Base URL: https://api.lassocut.com/v1.0. Every request carries your key in the X-Api-Key header. Requests are multipart/form-data, application/x-www-form-urlencoded or application/json. The API follows the remove.bg API: if your code already calls it, see the migration guide. To try every request without writing code, open the LassoCut collection in Postman.

curl --fail-with-body -H "X-Api-Key: $LASSOCUT_API_KEY" -F "image_file=@photo.jpg" -o out.png \
     https://api.lassocut.com/v1.0/removebg

POST/removebg

Removes the background of one image. A successful call returns the image bytes with the headers listed below. Send Accept: application/json to get {"data": {"result_b64": "…", "foreground_top": …, …}} instead.

Code examples

The curl and Python examples were run against the production API on 27 September 2026 and returned a PNG.

Full walkthroughs, with options and common errors for each language: curl, Python, Node.js, PHP.

curl

curl --fail-with-body -H "X-Api-Key: $LASSOCUT_API_KEY" \
     -F "image_file=@photo.jpg" \
     -F "size=auto" \
     -o no-bg.png \
     https://api.lassocut.com/v1.0/removebg

Python (official package)

lassocut on PyPI: Python 3.10 or later, no dependencies, retries on temporary errors. Source and full options: GitHub.

pip install lassocut

from lassocut import LassoCut

client = LassoCut()   # reads LASSOCUT_API_KEY
result = client.remove_background("photo.jpg", size="preview")
result.save("no-bg.png")
print("credits charged:", result.credits_charged)

Python (requests)

import os, requests

r = requests.post(
    "https://api.lassocut.com/v1.0/removebg",
    headers={"X-Api-Key": os.environ["LASSOCUT_API_KEY"]},
    files={"image_file": open("photo.jpg", "rb")},
    data={"size": "auto"},
)
r.raise_for_status()
open("no-bg.png", "wb").write(r.content)
print("credits charged:", r.headers["X-Credits-Charged"])

Node.js (18 or later, fetch)

import { readFile, writeFile } from "node:fs/promises";

const form = new FormData();
form.append("image_file", new Blob([await readFile("photo.jpg")]), "photo.jpg");
form.append("size", "auto");

const res = await fetch("https://api.lassocut.com/v1.0/removebg", {
  method: "POST",
  headers: { "X-Api-Key": process.env.LASSOCUT_API_KEY },
  body: form,
});
if (!res.ok) throw new Error(JSON.stringify(await res.json()));
await writeFile("no-bg.png", Buffer.from(await res.arrayBuffer()));

PHP (cURL)

<?php
$ch = curl_init("https://api.lassocut.com/v1.0/removebg");
curl_setopt_array($ch, [
    CURLOPT_HTTPHEADER => ["X-Api-Key: " . getenv("LASSOCUT_API_KEY")],
    CURLOPT_POSTFIELDS => ["image_file" => new CURLFile("photo.jpg"), "size" => "auto"],
    CURLOPT_RETURNTRANSFER => true,
]);
$png = curl_exec($ch);
if (curl_getinfo($ch, CURLINFO_HTTP_CODE) === 200) {
    file_put_contents("no-bg.png", $png);
} else {
    echo $png;
}

Image source (exactly one)

Output

Framing

Background

Subject type

Shadows

add_shadow=true (the older remove.bg flag) is accepted for compatibility; it asks for the car shadow, so it draws nothing today: use shadow_type=cast or drop. Invalid values return invalid_shadow_angle or invalid_shadow_length.

curl --fail-with-body -H "X-Api-Key: $LASSOCUT_API_KEY" \
     -F "image_file=@product.jpg" \
     -F "bg_color=ffffff" \
     -F "shadow_type=cast" -F "shadow_angle=45" -F "shadow_length=medium" \
     -o product-shadow.jpg \
     https://api.lassocut.com/v1.0/removebg

Marketplace presets

One field, preset, frames the cut-out to a marketplace's image rules: canvas size, white background, how much of the canvas the product fills, file format and file-size cap. Values: amazon, ebay, etsy, shopify, zalando, instagram, or none (default). Anything else returns invalid_preset. The values of each preset are listed by GET /presets and explained on the marketplace presets page.

curl --fail-with-body -H "X-Api-Key: $LASSOCUT_API_KEY" \
     -F "image_file=@product.jpg" \
     -F "preset=amazon" \
     -D headers.txt -o amazon.jpg \
     https://api.lassocut.com/v1.0/removebg
grep -i "^x-preset\|^x-compliance" headers.txt

• With a preset, crop, crop_margin, scale and position are ignored; the ones you sent are listed in the X-Preset-Ignored header.
• The preset picks the output format when format is auto. An explicit format or bg_color overrides the preset and makes the result non-compliant (X-Compliance: fail).
• channels=alpha with a preset returns preset_needs_rgba.
• A shadow is allowed on every preset except zalando; shadow_type and its options work as in Shadows. With a cast or 3D shadow, ebay, etsy, shopify and instagram leave more room around the product (it fills 70% on eBay and Shopify, 65% on Etsy and Instagram) and move it slightly away from the shadow, so the shadow stays visible; amazon keeps its 85% rule, with a shorter shadow.
• If the product had to be enlarged above its source size to fill the canvas, the response carries X-Upscaled: true.

Compliant means compliant with the image rules LassoCut checks: a marketplace can still refuse a photo for other reasons (text, props, watermarks). Rules as published on 19 October 2026.

Availability: the API, the web tool, the batch tool, the Shopify app, the WordPress plugin (1.2.0), n8n (0.2.0), Zapier (1.2.0), Make, the command line (1.2.0), AI assistants through MCP (1.1.0), Figma and Photoshop (1.2.0) support presets today; GIMP supports the cast shadow only (no preset, its result is a layer).

Response headers

GET/presets

The marketplace presets and their rules. Public: no API key needed. The response is cached for one hour.

curl https://api.lassocut.com/v1.0/presets

{"data": [{"id": "amazon",
  "names": {"en": "Amazon", "fr": "Amazon", "es": "Amazon", "pt": "Amazon", "de": "Amazon"},
  "rule": {"en": "Pure white background, product fills 85% of a square image, 2000 px", "fr": "…", "es": "…", "pt": "…", "de": "…"},
  "canvas": [2000, 2000], "background": [255, 255, 255], "fill": 0.85,
  "fill_min": 0.85, "fill_shadow": 0.85,
  "format": "jpg", "max_bytes": 10485760, "shadow_allowed": true, "shadow_default": false}, …]}

fill is how much of the canvas the product fills, fill_shadow the same with a cast or 3D shadow, and fill_min the marketplace's own minimum where it has one (null otherwise). Rules as published on 19 October 2026. Sources: the Shopify help centre, the eBay picture policy, Zalando's partner pages and Google Merchant Center's image guidelines; Amazon (Seller Central), Etsy and Instagram publish theirs behind a sign-in. A few values are conservative defaults pending confirmation on the official page (Amazon fill and file size, Etsy file size, Zalando background): see the presets page.

POST/compose

Frames, shadows and colours a cut-out you already have. It does not remove any background: image_file must be a PNG with transparency (for example a result from /removebg). It takes the same preset, shadow_type, shadow_angle, shadow_length, shadow_opacity, bg_color and format fields, and returns the same response headers. Nothing is stored.

curl --fail-with-body -H "X-Api-Key: $LASSOCUT_API_KEY" \
     -F "image_file=@cutout.png" \
     -F "preset=amazon" \
     -F "shadow_type=cast" \
     -D headers.txt -o amazon.jpg \
     https://api.lassocut.com/v1.0/compose

• Never charged: every result carries X-Credits-Charged: 0, and an error costs nothing either.
• Rate limit: counted on the larger of the image and the preset's canvas. Without a key, each visitor has a much smaller budget than an account.
• With an API key: up to full size. Without a key: up to 0.25 megapixels and 10 MB.
• bg_image_url and bg_image_file are not supported (compose_bg_image_unsupported).
• An image without transparency returns compose_needs_cutout; a size above the anonymous limit without a key returns compose_needs_account.

GET/account

Your balance. Free of charge.

{"data": {"attributes": {
  "credits": {"total": 200.0, "subscription": 0.0, "payg": 200.0, "enterprise": 0.0},
  "api": {"free_calls": 10, "sizes": "all"}}}}

Each account gets 50 free calls per calendar month, up to 10 a day, used before paid credits. Free calls cover previews only; full-size and 50 MP images always use credits. free_calls is the free previews you can use now: at most 10 today and what is left of the 50 this month.

POST/improve

Sends us an image the API got wrong, so the models can learn from it. Fields: image_file, image_file_b64 or image_url, plus optional image_filename and tag. Free of charge. Images sent here are kept; images sent to /removebg are not.

Errors

Errors return JSON: {"errors": [{"code": "…", "title": "…", "detail": "…"}]}. Nothing is charged on an error.

Limits

• Upload size: 22 MB.
• Output resolution: up to 25 MP (full) or 50 MP (50MP); PNG output up to 10 MP.
• Rate limit: 500 megapixel-images per minute per account. An image counts as its size in megapixels, rounded up, with a minimum of 1.
• The first call after a quiet period can take several seconds longer while a GPU starts.