> ## Documentation Index
> Fetch the complete documentation index at: https://docs.samsa.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Remove a background
> Submit a background-removal job — one source image — and get a transparent PNG back.
Remove the background from one source `image`, producing a transparent PNG. The call
returns **`202 Accepted`** with a job `id`; poll
[`GET /images/background-removals/{id}`](/api-reference/image-ops/get-background-removal)
for the result. The `image` takes **exactly one** of `image_id`, `url`, or
`base64` + `mime_type`. There is **no model parameter** — v1 uses the default
background-removal model. Requires the `images.transform` scope.
## Example: one source per mode
```bash image_id theme={null}
curl -X POST https://api.samsa.ai/public/v1/images/background-removals \
-H "Authorization: Bearer $SAMSA_API_KEY" \
-H "Content-Type: application/json" \
-d '{ "image": { "image_id": "123e4567-e89b-12d3-a456-426614174000" } }'
```
```bash url theme={null}
curl -X POST https://api.samsa.ai/public/v1/images/background-removals \
-H "Authorization: Bearer $SAMSA_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"image": { "url": "https://cdn.example.com/photo.png" },
"webhook_url": "https://example.com/webhooks/samsa"
}'
```
```bash base64 theme={null}
curl -X POST https://api.samsa.ai/public/v1/images/background-removals \
-H "Authorization: Bearer $SAMSA_API_KEY" \
-H "Content-Type: application/json" \
-d '{ "image": { "base64": "iVBORw0KGgoAAAANSUhEUg...", "mime_type": "image/png" } }'
```
The normal (charged) path returns a `pending` job:
```json 202 Accepted theme={null}
{
"id": "f7a8b9c0-1d2e-4f3a-4b5c-6d7e8f9a0b1c",
"status": "pending",
"estimated_credits": 1
}
```
**Cost = 1 credit on a miss; 0 on a cache hit.** When the source is an `image_id`
you own and a background-removed result already exists for it, the submit returns
`202` with `status: "completed"` and `estimated_credits: 0` **immediately** — no
new job is queued and your organization's concurrency cap is not consumed. Every
other case (an `https` `url`/`base64` source, or an owned `image_id` with no ready
result) is the normal charged path above.
```json 202 Accepted (cache hit) theme={null}
{
"id": "f7a8b9c0-1d2e-4f3a-4b5c-6d7e8f9a0b1c",
"status": "completed",
"estimated_credits": 0
}
```
## Errors
| Status | Code | When |
| ------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `402` | [`insufficient_credits`](/guides/errors#insufficient_credits) / [`insufficient_team_credits`](/guides/errors#insufficient_team_credits) / [`insufficient_unallocated_credits`](/guides/errors#insufficient_unallocated_credits) | The balance this credential can spend is below the job cost. Organizations with at least one active team get the team-aware codes instead of `insufficient_credits` (budget-exempt system organizations excepted). An operational failure inside the deduction can still surface as the generic `insufficient_credits`, whatever the regime. |
| `402` | [`subscription_inactive`](/guides/errors#subscription_inactive) | The organization has no usable subscription. |
| `403` | [`missing_scope`](/guides/errors#missing_scope) | Key lacks the `images.transform` scope. |
| `404` | [`not_found`](/guides/errors#not_found) | The source `image_id` is unknown, or not owned by the API key's creator — an image another member of your organization created is a `404` too. |
| `422` | [`validation_error`](/guides/errors#validation_error) | Zero or multiple source modes supplied. |
| `429` | [`rate_limited`](/guides/errors#rate_limited) / [`too_many_active_jobs`](/guides/errors#too_many_active_jobs) | Per-key rate window or per-org concurrency cap exceeded. |
## OpenAPI
````yaml api-reference/openapi.json POST /images/background-removals
openapi: 3.1.0
info:
title: Samsa API
description: >-
The Samsa public REST API. Authenticate with an organization API key as a
bearer token (`Authorization: Bearer samsa_sk_...`). Errors follow a single
envelope shape; every response carries an `X-Request-ID`.
version: 1.0.0
servers:
- url: https://api.samsa.ai/public/v1
security:
- BearerAuth: []
paths:
/images/background-removals:
post:
tags:
- Images
summary: Remove an image's background (transparent PNG)
description: >-
Submits a background-removal job — one source `image` — and returns
`202` immediately with the job `id` and a credit estimate; poll `GET
/images/background-removals/{id}` for the result (a transparent PNG).
The source is exactly one of `image_id` (an image in your organization's
context), an https `url`, or `base64`+`mime_type`. There is NO model
parameter — v1 uses the default background-removal model. **Cost = 1
credit on a miss; 0 on a cache HIT.** When the source is an `image_id`
you own and a background-removed result already exists for it, the
submit returns `202` with `status: "completed"` and `estimated_credits:
0` immediately — no new job is queued and the per-org concurrency cap is
not consumed (an at-cap org still gets its cached result); if a
`webhook_url` was given the `completed` event fires right away. Every
other case (an https `url`/`base64` source, or an owned `image_id` with
no ready result) is the normal charged path: `202` with `status:
"pending"` and `estimated_credits: 1`. Common errors: a foreign or
unknown `image_id` returns `404`; missing credits or no usable org
subscription returns `402`; the per-key rate limit or per-org
concurrency cap returns `429`. Requires the `images.transform` scope.
operationId: create_image_background_removal_images_background_removals_post
requestBody:
content:
application/json:
schema:
$ref: '#/components/schemas/PublicBackgroundRemovalRequest'
required: true
responses:
'202':
description: Successful Response
content:
application/json:
schema:
$ref: '#/components/schemas/PublicTransformAccepted'
'401':
description: Missing, invalid, expired, or revoked API key.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
'402':
description: Insufficient credits, or no usable org subscription.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
'403':
description: The API key lacks the required scope for this operation.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
'404':
description: Generation, or a referenced model/palette, not found.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
'409':
description: A referenced model is not ready for generation.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
'422':
description: Request validation failed (prompt, engine, resolution, ...).
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
'429':
description: Per-key rate limit or per-org concurrency cap exceeded.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
'500':
description: Internal server error.
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorEnvelope'
components:
schemas:
PublicBackgroundRemovalRequest:
properties:
image:
$ref: '#/components/schemas/PublicImageEditSource'
description: >-
The source image: exactly one of `image_id`, an https `url`, or
`base64`+`mime_type`.
webhook_url:
anyOf:
- type: string
- type: 'null'
title: Webhook Url
description: >-
Optional https webhook notified once on terminal status (signed per
the webhook signature scheme; see the webhooks docs). On a cache hit
the `completed` event fires immediately.
examples:
- https://example.com/webhooks/samsa
type: object
required:
- image
title: PublicBackgroundRemovalRequest
description: >-
`POST /images/background-removals` body (SAM-820 / S8.8 — ADR §7, §8,
§10).
Remove the background from ONE source `image`, producing a transparent
PNG.
The source is exactly one of `image_id` (an image in your organization's
context), an https `url`, or `base64`+`mime_type`. There is NO model
parameter — v1 uses the default background-removal model.
**Cost = 1 credit on a miss; 0 on a cache HIT.** When the source is an
`image_id` you own and a background-removed result already exists for
it, the
submit returns `202` with `status: "completed"` and `estimated_credits:
0`
immediately (no new job is queued and the org's concurrency cap is not
consumed). Every other case (an https `url`/`base64` source, or an owned
`image_id` with no ready result) is the normal charged path: `202` with
`status: "pending"` and `estimated_credits: 1`.
examples:
- image:
image_id: 123e4567-e89b-12d3-a456-426614174000
- image:
url: https://cdn.example.com/photo.png
webhook_url: https://example.com/webhooks/samsa
- image:
base64: iVBORw0KGgoAAAANSUhEUg...
mime_type: image/png
PublicTransformAccepted:
properties:
id:
type: string
format: uuid
title: Id
description: The job id — poll the op's `GET .../{id}` endpoint.
status:
$ref: '#/components/schemas/PublicImageStatus'
description: >-
Initial status: `pending` (job queued — enter the polling flow), or
`completed` with `estimated_credits: 0` when `background-removals` /
`vectorizations` serve an owned-image cache hit (the result is
immediately available).
examples:
- pending
estimated_credits:
type: integer
title: Estimated Credits
description: >-
Credits this job is expected to cost — `0` on a cache-hit
`completed` response.
examples:
- 5
type: object
required:
- id
- status
- estimated_credits
title: PublicTransformAccepted
description: >-
Shared `202` body for the transform-op submits (SAM-813 / S8 wave).
Every `POST /images/` returns the async job handle
`{id, status, estimated_credits}`. The initial `status` is `pending`
(the
job is queued), with ONE exception: `background-removals` and
`vectorizations` answer an owned-`image_id` cache hit (a ready result
already exists for that image) with `status: "completed"` and
`estimated_credits: 0` — no new job is queued, the `completed` webhook
event is emitted immediately for a supplied `webhook_url`, and the
result
is already available from the op's `GET .../{id}` endpoint. The other
transform ops (`img2img`, `variations`, `resizes`, `upscales`) always
start `pending`.
ErrorEnvelope:
properties:
error:
$ref: '#/components/schemas/ErrorDetail'
type: object
required:
- error
title: ErrorEnvelope
description: The complete public error body — an ``error`` object wrapper (ADR §5).
PublicImageEditSource:
properties:
image_id:
anyOf:
- type: string
format: uuid
- type: 'null'
title: Image Id
description: Id of an image in your organization's context to edit.
url:
anyOf:
- type: string
- type: 'null'
title: Url
description: https URL of the source image (downloaded under SSRF guards).
examples:
- https://cdn.example.com/photo.png
base64:
anyOf:
- type: string
- type: 'null'
title: Base64
description: Base64-encoded source image bytes (send with `mime_type`).
mime_type:
anyOf:
- type: string
- type: 'null'
title: Mime Type
description: >-
MIME type for a base64 source — one of: image/jpeg, image/png,
image/webp.
examples:
- image/png
type: object
title: PublicImageEditSource
description: >-
The source image for an edit — exactly one of three modes (ticket §1).
* `image_id` — an image already in the key creator's context (owned by
the key
creator; ownership is enforced in the route -> `404` on a miss).
* `url` — an `https` URL the server downloads under the SSRF guard
(§7.4).
* `base64` + `mime_type` — inline bytes (`mime_type` in the allow-list).
Exactly one mode must be supplied; zero or more than one is a `422`.
`url` / `base64` rasters must decode to at most **33,554,432 pixels**
(32 MP, width x height) — a larger source returns `422` naming the
source
param, before any charge (same ceiling the resize op documents).
PublicImageStatus:
type: string
enum:
- pending
- processing
- completed
- failed
- cancelled
title: PublicImageStatus
description: >-
Public image-job status — the lower-cased internal ``TaskStatus``.
Deliberately the plain lower-cased internal value (NOT the ADR §7.2
``PENDING -> queued`` remap): the ticket's 202 uses ``status:
"pending"`` and
its fixtures say ``pending/processing/completed/failed``, and this keeps
the
public surface consistent with the already-shipped models API
(``PublicModelStatus``).
ErrorDetail:
properties:
type:
type: string
title: Type
examples:
- authentication_error
code:
type: string
title: Code
examples:
- invalid_api_key
message:
type: string
title: Message
examples:
- The provided API key is invalid, expired, or revoked.
request_id:
type: string
title: Request Id
examples:
- 8f14e45fceea167a5a36dedd4bea2543
param:
anyOf:
- type: string
- type: 'null'
title: Param
description: Present on validation errors — names the offending field.
examples:
- aspect_ratio
type: object
required:
- type
- code
- message
- request_id
title: ErrorDetail
description: The ``error`` object of the public envelope (ADR §5).
securitySchemes:
BearerAuth:
type: http
scheme: bearer
description: >-
Organization API key as a bearer token: `Authorization: Bearer
samsa_sk_...`.
````