Car Cutout + Shadow (Base64)#

Base URL: https://api.withoutbg.com · Spec: openapi.json

Remove background from a car photo and return both the RGBA cutout and a soft cast-shadow mask as separate Base64 PNGs in one JSON body.

Cost: 1 credit on HTTP 200.

The cutout does not bake the shadow in; use shadow_base64 to composite or edit on the client. Window reconstruction is on by default (reconstruct_windows=true); set reconstruct_windows=false to skip. For a single RGBA with baked shadow, use /v1.0/car-image-without-background-base64 with include_shadow=true. No binary sibling. No image-type sidecar.

Endpoint#

POST /v1.0/car-cutout-and-shadow-base64

Base URL: https://api.withoutbg.com

Authentication#

Provide your API key in the request header:

API key header

X-API-Key: <your_api_key>

Request#

Content-Type: application/json

Fields#

image_base64 (string, required) — Input image as a raw Base64 string (no `data:` URI prefix). Supported formats: JPEG, PNG, WebP, AVIF, HEIC, TIFF, BMP, GIF. Maximum decoded size: 20.0 MB. Invalid Base64, non-image data, unsupported formats, or oversize payloads fail with HTTP 422.
reconstruct_windows (boolean, optional) — When true (default), run car window reconstruction on the cutout: opens glass interiors while keeping the car outline. Shadow is predicted from the BiRefNet silhouette regardless. Set false to skip window reconstruction.

Response#

Success Content-Type: application/json

Body fields#

input_dimensions (array<integer>, required) — Decoded input size as `[width, height]` (pixels).
processed_dimensions (array<integer>, required) — Size after server prep downscale (longest-side / megapixel caps) as `[width, height]`. Distinct from model inference resolution (~1024 long side).
was_downscaled (boolean, required) — True when the input was downscaled during server prep.
img_without_background_base64 (string, required) — Car cutout as Base64 PNG (RGBA) with transparent background. Shadow is not baked in; use `shadow_base64` to composite yourself. Prepend `data:image/png;base64,` to display in a browser.
shadow_base64 (string, required) — Soft cast-shadow mask as Base64 grayscale PNG (0 = no shadow, 255 = full shadow). Not composited into the cutout; for client-side editing/compositing. Prepend `data:image/png;base64,` to display in a browser.

Errors#

Status	Description	Detail
`401`	Invalid API Key	Invalid API Key
`402`	Insufficient credit. Please top up API credits.	Insufficient credit. Please top up API credits.
`403`	Credits Expired. Please top up API credits. If you have existing credits, they will be reactivated.	Credits Expired. Please top up API credits. If you have existing credits, they will be reactivated.
`422`	Validation error. Includes invalid Base64, non-image payloads, unsupported formats, and decoded size over 20.0 MB.	[object Object]
`429`	Rate limit exceeded (product policy: 30 requests/minute per API key). May be returned by the API gateway. Retry with exponential backoff.	{"error":"Too Many Requests","status":429,"message":"Rate limit exceeded. Please try again later"}
`500`	Internal Server Error	Internal Server Error. Please contact support: contact@withoutbg.com

Example (cURL)#

cURL

curl -X POST \
  -H "X-API-Key: $WITHOUTBG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"image_base64":"<raw_base64>"}' \
  "https://api.withoutbg.com/v1.0/car-cutout-and-shadow-base64"

Car Background Removal (Binary) — POST /v1.0/car-image-without-background
Car Background Removal (Base64) — POST /v1.0/car-image-without-background-base64

Contract sections are generated at build time from OpenAPI. Markdown mirror: /docs/pro-model/car-cutout-and-shadow-base64.md