Flux 2 Klein Base 4B Text to Image | High-Quality Text-to-Image API

FLUX.2 Klein Base 4B Text-to-Image

FLUX.2 Klein Base 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

Parameter	Required	Description
prompt	Yes	Text description of the image you want to generate
width	No	Output width in pixels (default: 1024)
height	No	Output height in pixels (default: 1024)
seed	No	Random seed for reproducibility (-1 for random)

How to Use

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

Pricing

Item	Cost
Per image	$0.01

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

Flux 2 Klein Base 4b Text To Image API — Quick start

Grab a WaveSpeedAI API key, then call POST https://api.wavespeed.ai/api/v3/wavespeed-ai/flux-2-klein-base-4b/text-to-image with your input as JSON. The endpoint returns a prediction id; poll the prediction endpoint until status flips to completed, then read the output URL from data.outputs[0]. Examples for Flux 2 Klein Base 4b Text To Image below.

HTTP example

# Submit the prediction
curl -X POST "https://api.wavespeed.ai/api/v3/wavespeed-ai/flux-2-klein-base-4b/text-to-image" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $WAVESPEED_API_KEY" \
  -d '{
    "prompt": "A cinematic shot of a city at sunset, soft golden light",
    "size": "1024*1024",
    "seed": -1,
    "enable_sync_mode": false,
    "enable_base64_output": false
}'

# Response includes a prediction id. Poll for the result:
curl -X GET "https://api.wavespeed.ai/api/v3/predictions/{request_id}/result" \
  -H "Authorization: Bearer $WAVESPEED_API_KEY"

# When status is "completed", read the output from data.outputs[0].

Node.js example

// npm install wavespeed
const WaveSpeed = require('wavespeed');

const client = new WaveSpeed(); // reads WAVESPEED_API_KEY from env

const result = await client.run("wavespeed-ai/flux-2-klein-base-4b/text-to-image", {
        "prompt": "A cinematic shot of a city at sunset, soft golden light",
        "size": "1024*1024",
        "seed": -1,
        "enable_sync_mode": false,
        "enable_base64_output": false
});

console.log(result.outputs[0]); // → URL of the generated output

Python example

# pip install wavespeed
import wavespeed

output = wavespeed.run(
    "wavespeed-ai/flux-2-klein-base-4b/text-to-image",
    {
    "prompt": "A cinematic shot of a city at sunset, soft golden light",
    "size": "1024*1024",
    "seed": -1,
    "enable_sync_mode": false,
    "enable_base64_output": false
}
)

print(output["outputs"][0])  # → URL of the generated output

Flux 2 Klein Base 4b Text To Image API — Frequently asked questions

What is the Flux 2 Klein Base 4b Text To Image API?

Flux 2 Klein Base 4b Text To Image is a WaveSpeedAI model for image generation, exposed as a REST API on WaveSpeedAI. FLUX.2 [klein] Base 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. You can call it programmatically or try it from the playground above.

How do I call the Flux 2 Klein Base 4b Text To Image API?

POST your input parameters to the model's REST endpoint (shown in the API tab of this playground) with your WaveSpeedAI API key in the Authorization header. Submission returns a prediction ID; poll the prediction endpoint until status flips to "completed", then read the output URL from the result. The playground generates a ready-to-paste code sample in Python, JavaScript, or cURL for whatever inputs you've set. Full request/response shape is documented at https://wavespeed.ai/docs/docs-api/wavespeed-ai/flux-2-klein-base-4b-text-to-image.

How much does Flux 2 Klein Base 4b Text To Image cost per run?

Flux 2 Klein Base 4b Text To Image starts at $0.010 per run. That figure is the base price — the final charge scales with the parameters you set in the form (output size, length, count, references, or whatever knobs this model exposes), so a higher-quality or larger output costs more than a minimal one. The exact cost for your current input is shown live next to the Generate button before you submit, and the actual per-call charge is recorded on the prediction afterwards.

What inputs does Flux 2 Klein Base 4b Text To Image accept?

Key inputs: `prompt`, `size`, `seed`, `enable_base64_output`, `enable_sync_mode`. The full JSON schema (types, defaults, allowed values) is rendered above the Generate button and mirrored in the API reference at https://wavespeed.ai/docs/docs-api/wavespeed-ai/flux-2-klein-base-4b-text-to-image.

How do I get started with the Flux 2 Klein Base 4b Text To Image API?

Sign up for a free WaveSpeedAI account to claim starter credits, copy your API key from /accesskey, then call the endpoint shown in the API tab of the playground. The playground also auto-generates a code sample in Python, JavaScript, or cURL for the parameters you've set.

Can I use Flux 2 Klein Base 4b Text To Image outputs commercially?

Commercial usage rights depend on the model's license, set by its provider (WaveSpeedAI). The license summary appears on the model card above; see WaveSpeedAI's Terms of Service for platform-level conditions.

ExamplesView all

Related Models

README

FLUX.2 Klein Base 4B Text-to-Image

Why Choose This?

Parameters

How to Use

Pricing

Best Use Cases

Pro Tips

Notes

Related Models

Flux 2 Klein Base 4b Text To Image API — Quick start

Flux 2 Klein Base 4b Text To Image API — Frequently asked questions