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POST

Authorizations

x-key
string
header
required

Body

application/json

FLUX 3 Image Klein: text-to-image, or editing with up to 10 reference images.

prompt
string
required

Free-form prompt describing the image.

images

Optional reference image(s), each an http(s) URL or base64, one to 10 total. The first is the image being edited and sets the default output size.

aspect_ratio
default:auto

Output aspect ratio, as in flux-3-image. auto (default): for edits, the first reference's exact aspect; for text-to-image, a ratio picked from the prompt (prompt rewrite, else ratio keywords, else 16:9) at the requested tier. Ignored when width and height are set.

Available options:
21:9,
2:1,
16:9,
3:2,
7:5,
4:3,
5:4,
1:1,
4:5,
3:4,
5:7,
2:3,
9:16,
1:2,
9:21
resolution
enum<string> | null

Equal-area size tier, as in flux-3-image: 768sq, 1k, 1.5k, 2k or 4k. Omitted: 1k for text-to-image; for edits the first reference's own size, or its nearest tier when aspect_ratio is set. Ignored when width and height are set.

Available options:
768sq,
1k,
1.5k,
2k,
4k
width
integer | null

Exact output width in pixels, [64, 6256]; set together with height. Overrides resolution and aspect_ratio.

height
integer | null

Exact output height in pixels, [64, 6256]; width x height at most 16822272 pixels (16.8 MP, the largest 4k bin).

seed
integer | null

Seed for reproducibility; random when omitted.

Required range: 0 <= x <= 4294967295
safety_tolerance
integer
default:2

Harm moderation tolerance from 0 to 7, with 0 the strictest. The route and organization determine the approved maximum and per-category ceilings. Unapproved levels return 422 with approved levels.

Required range: 0 <= x <= 7
output_format
enum<string>
default:jpeg

Output image format: jpeg (default) or png.

Available options:
jpeg,
png
steps
integer | null

Denoising steps (default 16).

Required range: 1 <= x <= 16

Response

Successful Response

id
string
required
polling_url
string
required
cost
number | null

Cost in credits for this request

input_mp
number | null

Input megapixels (2 decimal places)

output_mp
number | null

Output megapixels (2 decimal places)