Flux 2 Klein 9b Text To Image

Flux 2 Klein 9b Text To Image

Playground

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FLUX.2 [klein] 9B is a high-quality text-to-image model with 9B parameters, offering enhanced realism and crisper text generation. Ready-to-use REST inference API, best performance, no cold starts, affordable pricing.

Features

FLUX.2 Klein 9B Text-to-Image is a powerful text-to-image generation model with 9B parameters. Describe your vision in text and get high-quality images with strong prompt adherence — delivering better detail and understanding than the 4B variant at an affordable price.


Why Choose This?

  • Enhanced quality 9B parameter model delivers richer detail and better prompt understanding than the 4B variant.

  • Strong prompt adherence Accurately interprets detailed prompts to generate images that match your description.

  • Flexible sizing Custom width and height controls for any aspect ratio.

  • Prompt Enhancer Built-in tool to automatically improve your prompts for better results.

  • Balanced performance More capable than 4B while remaining fast and affordable.


Parameters

ParameterRequiredDescription
promptYesText description of the image you want to generate
widthNoOutput width in pixels (default: 1024)
heightNoOutput height in pixels (default: 1024)
seedNoRandom seed for reproducibility (-1 for random)

How to Use

  1. Write your prompt — describe the image including subject, style, lighting, and mood.
  2. Set size — adjust width and height for your desired dimensions.
  3. Set seed — use -1 for random, or specify a number for reproducibility.
  4. Run — submit and download the generated image.

Pricing

ItemCost
Per image$0.01

Simple flat-rate pricing regardless of image size.


Best Use Cases

  • High-Quality Generation — When 4B quality isn’t enough but full-size models are overkill.
  • Production Work — Balanced quality and cost for professional content.
  • Creative Projects — Detailed illustrations, concept art, and visual designs.
  • Batch Generation — Affordable pricing enables large-scale image production.
  • Rapid Prototyping — Fast generation for creative iteration.

Pro Tips

  • Be specific in your prompts — include subject, style, lighting, colors, and atmosphere.
  • Use the same seed to reproduce identical outputs or compare prompt variations.
  • Start with 1024x1024 for balanced quality, adjust dimensions for specific needs.
  • Need custom styles? Try FLUX.2 Klein 9B Text-to-Image LoRA.

Notes

  • 9B model offers better detail than 4B at slightly higher cost.
  • For best results, write detailed, descriptive prompts.

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",
  "size": "1024*1024",
  "seed": -1
}
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-2-klein-9b/text-to-image" \
  -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 "${PREDICTION_ID}" ]; then
  printf 'Submission response did not contain a prediction id
' >&2
  exit 1
fi
RESULT_URL=$(printf '%s' "${TASK}" | jq -r '.urls.get // empty')
if [ -z "${RESULT_URL}" ]; then RESULT_URL="https://api.wavespeed.ai/api/v3/predictions/${PREDICTION_ID}/result"; fi

# 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) printf '%s\n' "${RESULT}" | jq . >&2; exit 1 ;;
    created|processing) sleep 2 ;;
    *) printf 'Unexpected status: %s
' "${STATUS}" >&2; exit 1 ;;
  esac
done

Parameters

Task Submission Parameters

Request Parameters

ParameterTypeRequiredDefaultRangeDescription
promptstringYes--
sizestringNo1024*1024--
seedintegerNo-1--
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.urls.getstringURL to retrieve the prediction result
data.statusstringStatus of the task: created, processing, completed, or failed
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.urls.getstringURL to poll for the prediction result
data.statusstringStatus: created, processing, completed, or failed
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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