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Flux 2 Klein 4b Text To Image

Flux 2 Klein 4b Text To Image

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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

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

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$0.008

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.

Authentication

For authentication details, please refer to the Authentication Guide.

API Endpoints

Submit Task & Query Result


# Submit the task
curl --location --request POST "https://api.wavespeed.ai/api/v3/wavespeed-ai/flux-2-klein-4b/text-to-image" \
--header "Content-Type: application/json" \
--header "Authorization: Bearer ${WAVESPEED_API_KEY}" \
--data-raw '{
    "size": "1024*1024",
    "seed": -1,
    "enable_sync_mode": false,
    "enable_base64_output": false
}'

# Get the result
curl --location --request GET "https://api.wavespeed.ai/api/v3/predictions/${requestId}/result" \
--header "Authorization: Bearer ${WAVESPEED_API_KEY}"

Parameters

Task Submission Parameters

Request Parameters

ParameterTypeRequiredDefaultRangeDescription
promptstringYes-
sizestringNo1024*1024256 ~ 1536 per dimension
seedintegerNo-1-1 ~ 2147483647
enable_sync_modebooleanNofalse-If set to true, the function will wait for the result to be generated and uploaded before returning the response. It allows you to get the result directly in the response. This property is only available through the API.
enable_base64_outputbooleanNofalse-If enabled, the output will be encoded into a BASE64 string instead of a URL. This property is only available through the API.

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.outputsarrayArray of URLs to the generated content (empty when status is not completed)
data.urlsobjectObject containing related API endpoints
data.urls.getstringURL to retrieve the prediction result
data.has_nsfw_contentsarrayArray of boolean values indicating NSFW detection for each output
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, the ID of the prediction to get
data.modelstringModel ID used for the prediction
data.outputsstringArray of URLs to the generated content (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
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