Flux 2 Klein 4b Text To Image

Flux 2 Klein 4b Text To Image

Playground

FLUX.2 [klein] 4B is a compact 4-billion-parameter text-to-image model that delivers fast generation with quality results. Ready-to-use REST inference API, best performance, no cold starts, affordable pricing.

Features

FLUX.2 Klein 4B Text-to-Image is a lightweight yet capable text-to-image generation model. Describe your vision in text and get quality images with fast generation — the most affordable option in the FLUX.2 Klein family.

Why Choose This?

• Fast and affordable 4B parameter model optimized for quick turnaround at the lowest cost in the Klein series.

• Good prompt adherence Accurately interprets 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.

• Best value Ideal for rapid prototyping, batch processing, and budget-conscious projects.

Parameters

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

Simple flat-rate pricing regardless of image size.

Best Use Cases

• Rapid Prototyping — Quickly test ideas and concepts at minimal cost.
• Batch Generation — Lowest cost enables large-scale image production.
• Creative Exploration — Iterate on prompts without budget concerns.
• Drafts and Mockups — Generate initial visuals before refining with higher-tier models.
• Learning and Testing — Experiment with prompting techniques affordably.

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 higher quality? Try FLUX.2 Klein 9B Text-to-Image.
• Need custom styles? Try FLUX.2 Klein 4B Text-to-Image LoRA.

Notes

• Most affordable option in the FLUX.2 Klein series.
• For best results, write detailed, descriptive prompts.

Related Models

• FLUX.2 Klein 4B Text-to-Image LoRA — With LoRA support for custom styles.
• FLUX.2 Klein 4B Edit — Image editing model.
• FLUX.2 Klein 9B Text-to-Image — Higher quality 9B version.
• FLUX.2 Pro — Flagship-quality text-to-image generation.

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-4b/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

Response Parameters

Result Request Parameters

Result Response Parameters