Flux 3 Klein Image Base Edit LoRA API Documentation

Flux 3 Klein Image Base Edit LoRA API Documentation

Playground

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FLUX 3 Klein Base Image Edit LoRA edits and composes images from up to 3 reference images and a text prompt with up to 3 custom LoRA weights, with 1K or 2K output. Ready-to-use REST inference API, best performance, no coldstarts, affordable pricing.

Features

FLUX 3 Klein Base Image Edit LoRA runs the full, non-distilled FLUX 3 Klein checkpoint for maximum fidelity (slower and priced higher than Distilled) from Black Forest Labs (5.6B open weights). Edit existing images, or combine up to 3 reference images, with a natural-language instruction. Apply up to 3 custom LoRA weights in the same request.


Why Choose This?

  • Reference-guided editing
    Pass 1 to 3 reference images; the first image sets the output shape unless aspect_ratio is given.

  • Multi-reference composition
    Combine subjects and scenes from several images into one result.

  • LoRA support
    Apply up to 3 LoRAs, each as {path, scale}.

  • Text rendering
    Clear, readable text inside generated images.

  • Layout control with bounding boxes
    Append a JSON list of boxes on a 0 to 1000 grid to place elements; in edits, refer to the n-th reference as <ref_image_n>.

  • 1K and 2K output
    Choose 1k (~1 megapixel) or 2k (~4 megapixels) at 15 aspect ratios.

  • Multiple output formats
    Export as jpeg, png, or webp.

  • Seed control
    Use a fixed seed to reproduce a result, or -1 for random.


Parameters

ParameterRequiredDescription
promptYesText prompt describing the desired edit.
imagesYesReference image URLs. Supports between 1 and 3 images.
lorasNoUp to 3 LoRA objects. Each item uses {path, scale}.
resolutionNoOutput resolution tier: 1k or 2k. Default: 1k.
aspect_ratioNoOutput aspect ratio. Default: follows the first reference image.
output_formatNojpeg, png, or webp. Default: jpeg.
seedNoRandom seed. Use -1 for a random seed.

Pricing

  • 1k: $0.050 with one reference image, plus $0.025 for each additional reference image.
  • 2k: $0.185 with one reference image, plus $0.050 for each additional reference image.

How to Use

  1. Write a prompt — Describe the subject, composition, background, lighting, and style in full sentences.
  2. Add reference images — Provide 1 to 3 image URLs in images.
  3. Add LoRAs (optional) — Up to 3, each with its own scale.
  4. Choose resolution and aspect ratio (optional).
  5. Submit — Retrieve the finished image from the result.

Authentication

For authentication details, please refer to the Authentication Guide.

API Endpoints

Submit Task & Query Result

set -euo pipefail

export WAVESPEED_API_KEY="your-api-key"

REQUEST_BODY=$(cat <<'JSON'
{
  "prompt": "A cinematic ocean wave at sunrise, highly detailed",
  "images": [
    "https://interactive-examples.mdn.mozilla.net/media/cc0-images/painted-hand-298-332.jpg"
  ],
  "aspect_ratio": "1:1",
  "resolution": "1k",
  "output_format": "jpeg"
}
JSON
)

# 1. Submit the prediction.
SUBMIT_RESPONSE=$(curl --silent --show-error --fail-with-body \
  -X POST "https://api.wavespeed.ai/api/v3/wavespeed-ai/flux-3-klein-image-base/edit-lora" \
  -H "Authorization: Bearer ${WAVESPEED_API_KEY}" \
  -H "Content-Type: application/json" \
  -d "${REQUEST_BODY}")

TASK=$(printf '%s' "${SUBMIT_RESPONSE}" | jq 'if type == "object" and has("data") then .data else . end')
PREDICTION_ID=$(printf '%s' "${TASK}" | jq -r '.id // empty')
if [ -z "${PREDICTION_ID}" ]; then
  printf 'Submission response did not contain a prediction id
' >&2
  exit 1
fi
RESULT_URL="https://api.wavespeed.ai/api/v3/predictions/${PREDICTION_ID}/result"

# 2. Poll until the prediction finishes.
while true; do
  RESPONSE=$(curl --silent --show-error --fail-with-body \
    "${RESULT_URL}" \
    -H "Authorization: Bearer ${WAVESPEED_API_KEY}")
  RESULT=$(printf '%s' "${RESPONSE}" | jq 'if type == "object" and has("data") then .data else . end')
  STATUS=$(printf '%s' "${RESULT}" | jq -r '.status // empty')

  case "${STATUS}" in
    completed) printf '%s\n' "${RESULT}" | jq '.outputs'; break ;;
    failed|cancelled|timeout|deleted) printf '%s\n' "${RESULT}" | jq . >&2; exit 1 ;;
    *) sleep 2 ;;
  esac
done

Parameters

Task Submission Parameters

Request Parameters

ParameterTypeRequiredDefaultRangeDescription
promptstringYes-The edit instruction describing the desired result. To place or move elements with bounding boxes, refer to the n-th reference as <ref_image_n>.
imagesarray<string>Yes-1 ~ 3 itemsReference images to edit from (1 to 3 URLs). The first image also sets the output aspect ratio unless aspect_ratio is given.
aspect_ratiostringNo-1:1, 1:2, 2:1, 1:3, 3:1, 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 9:21, 21:9The output aspect ratio. Defaults to the first reference image.
resolutionstringNo1k1k, 2kTotal output resolution tier: 1k (~1 megapixel) or 2k (~4 megapixels).
output_formatstringNojpegjpeg, png, webpThe format of the output image.
lorasarray<object>No0 ~ 3 itemsList of LoRAs to apply (max 3).
loras[].pathstringYes---
loras[].scalenumberNo10 ~ 4-
seedintegerNo--The random seed. -1 means random.
enable_sync_modebooleanNofalse-If set to `true`, the request attempts to wait for the generated result and return outputs in the same response. If the result is not ready within the sync wait window, the API can return a timeout body while the task continues processing. This option is only available via the API and is supported only by some models.
enable_base64_outputbooleanNofalse-If set to `true`, the prediction's `output` strings are returned as **naked base64** (no `data:<mime>;base64,` prefix). When `false` (default), outputs are returned as URLs pointing to our CDN.

Response Parameters

ParameterTypeDescription
codeintegerHTTP status code (e.g., 200 for success)
messagestringStatus message (e.g., “success”)
data.idstringUnique identifier for the prediction, Task Id
data.modelstringModel ID used for the prediction
data.outputsarrayOutput values, usually URL strings; some models return text strings or structured result objects (empty when status is not completed)
data.urlsobjectObject containing related API endpoints
data.statusstringTask status. completed is successful; failed, cancelled, timeout, and deleted are failure terminal statuses.
data.created_atstringISO timestamp of when the request was created (e.g., “2023-04-01T12:34:56.789Z”)
data.errorstringError message (empty if no error occurred)
data.timingsobjectObject containing timing details
data.timings.inferenceintegerInference time in milliseconds

Result Request Parameters

ParameterTypeRequiredDefaultDescription
idstringYes-Task ID

Result Response Parameters

ParameterTypeDescription
codeintegerHTTP status code (e.g., 200 for success)
messagestringStatus message (e.g., “success”)
dataobjectThe prediction data object containing all details
data.idstringUnique identifier for the prediction
data.modelstringModel ID used for the prediction
data.outputsarray<string | object>Array of generated outputs (empty when status is not completed). Items are usually URL strings, but may be text strings or structured result objects, depending on the model.
data.urlsobjectObject containing related API endpoints
data.statusstringStatus: completed is successful; failed, cancelled, timeout, and deleted are failure terminal statuses
data.created_atstringISO timestamp of when the request was created
data.errorstringError message (empty if no error occurred)
data.timingsobjectObject containing timing details
data.timings.inferenceintegerInference time in milliseconds
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