FLUX 3 Klein Base API

About FLUX 3 Klein Base

Full-quality FLUX 3 Klein images and edits up to 2K.

Call it with the model name black-forest-labs/flux-3-klein-base/edit on POST /jobs/createTask, from 9 credits per image ($0.09).

Introduction

FLUX 3 Klein Base Image editing changes or combines one to three source images from a written instruction on Black Forest Labs' FLUX 3 Image Klein Base, the undistilled 5.6B checkpoint. Refer to sources as image 1, image 2 and image 3, keep the first image's shape with auto or pick one of fifteen, and choose 1k or 2k. Edits took about 20 to 40 seconds at 1k in our tests, and nothing is filtered.

Choose a mode by starting material

Key features

Garments from a product shot

Give the person as image 1 and a garment photographed on a hanger as image 2, and the edit dresses one in the other.

Same person, new place

Face, beard and build carried through a full change of outfit and setting: a hiker in a red jacket in a snowy forest became the same man in an open linen shirt on a cedar bench. Short, concrete instructions held faces best.

Combine up to three images

Two separate photos of two women became one scene on a sauna bench in matching dresses, both faces recognisable. With three sources, say what each one brings so nothing is dropped.

Request parameters

Pricing

Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.

Each task is rounded up to whole credits, so one run at the lowest tier costs 9 credits per image ($0.09).

For an exact number before you run, send the same body to POST /jobs/quote.

Use cases

Lookbooks and styling

Put a garment from a product photo on a model from another photo, in a new place and light, for lookbooks and mood boards.

Location and wardrobe changes

Move a person into a new setting and outfit in one pass while keeping who they are, for character sheets and series.

Prompt guide & pro tips

Use image numbers

Write image 1, image 2 and image 3 in upload order and give each a role: the woman from image 1, the dress from image 2. The first image also sets the shape when the aspect ratio is auto.

Protect first, then change

Start with what must stay the same, such as face, hair and build, then describe the change: garment, place, pose and light. The model may leave clothing in place, so say exactly what the person should wear.

API quick start

Call the FLUX 3 Klein Base API in three steps

1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
2. Send the request. POST /jobs/createTask with model black-forest-labs/flux-3-klein-base/edit and an input object that follows the parameter table. The response returns a task ID straight away.
3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.

# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "black-forest-labs/flux-3-klein-base/edit",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
    "image_urls": [
      "https://media.popnow.ai/influencer/examples/marco.webp"
    ],
    "aspect_ratio": "auto",
    "resolution": "1k",
    "output_format": "jpeg"
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

FLUX 3 Klein Base API questions

More about FLUX 3 Klein Base

Try it

FLUX 3 Klein Base AI Image Generator onlineCreate images with FLUX 3 Klein Base in PopNow

Endpoints

FLUX 3 Klein Base · Create Image

Docs

FLUX 3 Klein Base model ID and input schema in the API docsPopNow API quickstart: your first request in five minutesImage generation guide for the PopNow APIWebhooks: get FLUX 3 Klein Base results without polling