FLUX.2 Klein Base 9B LoRA API

About FLUX.2 Klein Base 9B LoRA

FLUX.2 Klein Base 9B LoRA runs Black Forest Labs' undistilled FLUX.2 [klein] Base 9B with up to three of your own LoRA files per request. Base is the build its makers recommend for fine-tuning and LoRA training: slower than the distilled klein 9B, with softer, more varied pictures.

Call it with the model name black-forest-labs/flux-2-klein-base-9b-lora/text-to-image on POST /jobs/createTask, from 4 credits per image ($0.04). New accounts get 30 free credits to try it in the Playground first.

Introduction

FLUX.2 Klein Base 9B LoRA Text to image draws one image from a written prompt on Black Forest Labs' FLUX.2 [klein] Base 9B, the undistilled 9B model its makers recommend for fine-tuning and LoRA training, with up to three of your own LoRA files loaded. Choose one of nine aspect ratios at 1k or 2k. Base is slower than the distilled klein 9B and gives softer, more varied pictures.

Choose a mode by starting material

Key features

The build LoRAs are trained on

A LoRA trained on klein Base 9B runs here on the model it was trained against, which is the cleanest place to judge it. LoRAs trained on the distilled klein 9B loaded as well in our tests; FLUX.1 and klein 4B LoRAs ran without an error and changed nothing.

Softer, more varied pictures

Without any LoRA, Base drew natural, film-like light and skin and more variety from seed to seed than the distilled build. Its makers run it at 50 sampling steps against four for the distilled build, which is why it takes longer.

Clean A/B checks

In our text-to-image tests a repeated seed returned identical pixels, so a pair of images with and without a LoRA shows exactly what the LoRA adds.

Request parameters

Pricing

Prices are in credits, the same credits you use on the website (1 credit = $0.01). The hold is taken when the task is accepted and settled to the actual charge when it finishes; failed tasks are refunded.

Each task is rounded up to whole credits, so one run at the lowest tier costs 4 credits per image ($0.04).

For an exact number before you run, send the same body to POST /jobs/quote.

Use cases

Checking a LoRA you trained

Run your file on Base at 1k or 2k and compare it against the same seed without it before you build on it or move it to the faster distilled build.

Natural stills

Portraits and interiors with soft light and believable skin, in nine shapes up to 2048 pixels, when you can wait half a minute per image.

Prompt guide & pro tips

Trigger first

Put the LoRA's trigger phrase at the start, then describe the picture in full sentences: subject, clothing, place, light and lens. There is no negative prompt, so state what you want to see.

One change per pair

Keep the seed fixed and change one thing at a time: the LoRA, its scale or one sentence. On Base the repeat is exact in text to image, so every difference you see comes from that one change.

Budget the time

About 20 seconds at 1k and around 35 at 2k in our tests, two to five times the distilled build. Send requests in parallel rather than waiting on each one, and use 1k while you are still choosing a scale.

API quick start

Call the FLUX.2 Klein Base 9B LoRA API in three steps

1. Create an API key. Sign in to PopNow and create a key in the API console. Keys start with sk-popnow- and use the same credits as the website.
2. Send the request. POST /jobs/createTask with model black-forest-labs/flux-2-klein-base-9b-lora/text-to-image and an input object that follows the parameter table. The response returns a task ID straight away.
3. Get the result. Poll GET /jobs/recordInfo with the task ID, or pass a callBackUrl and we post the result to it. Download the output links when the task succeeds.

# 1. Create the task. Keep the Idempotency-Key if you retry after a network error.
export IDEMPOTENCY_KEY="$(uuidgen)"
curl -X POST https://api.popnow.ai/api/v1/jobs/createTask \
  -H "Authorization: Bearer $POPNOW_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $IDEMPOTENCY_KEY" \
  -d '{
  "model": "black-forest-labs/flux-2-klein-base-9b-lora/text-to-image",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
    "aspect_ratio": "1:1",
    "resolution": "1k"
  }
}'

# 2. Copy data.taskId from the response, then poll until state is succeeded, failed, canceled or expired.
TASK_ID="TASK_ID_FROM_RESPONSE"
curl "https://api.popnow.ai/api/v1/jobs/recordInfo?taskId=$TASK_ID" \
  -H "Authorization: Bearer $POPNOW_API_KEY"

Replace the prompt and any links with your own. The API tab has the response, polling and callback reference.

FLUX.2 Klein Base 9B LoRA API questions

All FLUX models

FLUX.2 Klein 9B LoRA renders in about ten seconds with a more polished photographic finish.

• FLUX.2 Max APITop-tier FLUX: photoreal light and exact brand colorsFrom 11 credits per image
• FLUX 3 APIVideo with synced sound and a quick draft tierFrom 45 credits for a 5-second clip
• FLUX.2 Klein 9B LoRA APIFast FLUX.2 Klein 9B that loads up to three of your LoRAsFrom 3 credits per image
• FLUX.2 Klein Base 9B LoRA APIUndistilled Klein 9B for varied looks with your LoRAsFrom 4 credits per image
• FLUX.2 Klein 4B LoRA APISmall, quick FLUX.2 Klein 4B with your own LoRAsFrom 3 credits per image
• FLUX.2 Klein Base 4B LoRA APIUndistilled Klein 4B that loads your own LoRAsFrom 3 credits per image
• FLUX.2 Klein 9B APIFast FLUX edits that keep faces and poses intactFrom 2 credits per image
• FLUX.2 Klein 4B APIThe smallest, quickest FLUX for rapid draftsFrom 2 credits per image
• FLUX.2 Dev LoRA APIFLUX.2 Dev images and edits with your own LoRAsFrom 4 credits per image
• FLUX.2 Pro APIPhotoreal images with readable text and hex color controlFrom 5 credits per image
• FLUX.2 Flex APISpells headlines and labels exactly as writtenFrom 9 credits per image
• FLUX.2 Dev APIOpen-weights FLUX that can merge people into one sceneFrom 2 credits per image
• FLUX.1 Krea Dev LoRA APIPhotographic FLUX.1 Krea with your own LoRAsFrom 4 credits per image
• FLUX.1 Dev ControlNet LoRA APIPose, depth or edge control on FLUX.1 with your LoRAsFrom 6 credits per image
• FLUX.1 Fill Dev LoRA APIMasked inpainting on FLUX.1 Fill with your own LoRAsFrom 7 credits per image
• FLUX.1 Dev LoRA APIClassic FLUX.1 Dev with up to three of your LoRAsFrom 3 credits per image
• FLUX.1 Schnell LoRA APIFast FLUX.1 Schnell that loads your own LoRAsFrom 1 credit per image

Other image APIs

• Qwen Image 2.1 LoRA APIQwen Image 2.1 images and edits with up to three of your LoRAsFrom 5 credits per image
• MiniMax H3 Image LoRA APIH3 stills and edits with up to three of your LoRAsFrom 7 credits per image
• Anima Turbo LoRA APIAnime art with your own style or character LoRAsFrom 3 credits per image
• Krea 2 Turbo LoRA APIKrea 2 Turbo images and restyles with your own LoRAsFrom 4 credits per image
• P-Image LoRA APIFast P-Image renders and edits with one LoRA of your ownFrom 1 credit per image
• Z-Image Base LoRA APIZ-Image Base with up to three of your own LoRAsFrom 3 credits per image

More about FLUX.2 Klein Base 9B LoRA

Try it

FLUX.2 Klein Base 9B LoRA AI Image Generator onlineCreate images with FLUX.2 Klein Base 9B LoRA in PopNow

Docs

FLUX.2 Klein Base 9B LoRA model ID and input schema in the API docsPopNow API quickstart: your first request in five minutesImage generation guide for the PopNow APIWebhooks: get FLUX.2 Klein Base 9B LoRA results without polling