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Backgrounds

Full-frame pixel art scene art at any resolution up to 8K. Menu screens, level backdrops, parallax layers. Prompt-driven, or hand it a rough sketch and it keeps your composition.

Open to every key. In the web app this mode is subscriber-only; over the API it just spends top-up credits, no plan needed.

POST /backgrounds

POST /api/v1/backgrounds 4 CR EPIC · 15 CR MYTHIC

Field	Type	Notes
prompt	string	Max 1000 chars. Required unless a sketch is attached
sketch_b64	string	Optional rough drawing; the scene follows its composition. With a sketch, the prompt becomes layered instructions
style_notes	string	Max 500 chars of extra style direction
quality	string	`epic` (default) or `mythic`
width, height	int	Final output resolution, default 1920x1080, up to 7680x4320
pixel_scale	int	2 to 24, default 6. Size of one art pixel in the final image; higher = chunkier art
max_colours	int	Palette size, default 32
detail	int	1 minimal / 2 balanced (default) / 3 rich
contrast, saturation	float	1.0 = unchanged
crop_x, crop_y	float 0-1	Crop anchor when the generation canvas aspect differs from your target, default centred (0.5)

Python:

import base64, requests

r = requests.post(
    "https://spritelab.dev/api/v1/backgrounds",
    headers={"Authorization": "Bearer sl_live_YOUR_KEY"},
    json={
        "prompt": "misty pine forest at dawn, mountains behind, god rays",
        "width": 1920, "height": 1080,
        "pixel_scale": 6,
    },
    timeout=180,
)
r.raise_for_status()
out = r.json()
open("forest_1080.png", "wb").write(base64.b64decode(out["image_b64"]))
open("forest_native.png", "wb").write(base64.b64decode(out["native_b64"]))

Response envelope:

{
  "id": "c9d0…",
  "mode": "backgrounds",
  "image_b64": "…",           # final image at the requested resolution
  "native_b64": "…",          # native pixel grid: one image px per art px
  "width": 1920, "height": 1080,
  "grid_w": 320, "grid_h": 180,
  "cost": 4,
  "credits_remaining": 366
}

Notes

The final image is the native grid scaled up by a clean integer factor, so pixels stay square and crisp at any target resolution.
Big targets mean big responses. At 4K+ the base64 final can run to tens of MB. The lean pattern: take native_b64 and nearest-neighbour upscale it yourself; it's the same picture.
Scene art is opaque full-frame output. No transparency, no outline: different pipeline from sprites.