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black-forest-labs/flux-2-flex/editFrom 18 credits per image· Edit Image

FLUX.2 [flex] editing takes one to three source images and an instruction such as new light, a combined scene or added text. It works at 1k and keeps the source shape or offers nine shapes.

Call it with the model name black-forest-labs/flux-2-flex/edit on POST /jobs/createTask, from 18 credits per image ($0.18). New accounts get 30 free credits to try it in the Playground first.

  • Create Image
  • Edit Image
  • Up to 2K
  • Up to 3 reference images
  • 9 aspect ratios
by Black Forest LabsGet API keyFLUX.2 Flex examples and prompts →

Introduction

FLUX.2 [flex] Edit runs Black Forest Labs' FLUX.2 [flex] on images you already have. It takes one to three sources and an instruction, such as new light, a new scene or added lettering, and returns a 1k result in the source shape or one of nine shapes.

Choose a mode by starting material

What you haveMode
a written briefFLUX.2 [flex] Text to image
images to change or combineFLUX.2 [flex] Edit

Key features

Relighting with the subject kept

In our test a daytime portrait became a rainy night with wet stones, shop-window light and raindrops, while the woman, her coat and her pose stayed as they were.

Compositing with several sources

Refer to each source by number and say how they combine. Our perfume test placed a bottle from one photo onto a marble ledge from another and matched the light and reflection.

Text added over the result

Quote any headline or label you want added. Our composite came back with the headline spelled as written; a "No." in a label can come back as the numero sign.

Request parameters

ParameterRequiredDescription
aspect_ratioNoThe shape of the frame: wide, square or tall. auto · 1:1 · 16:9 · 9:16 · 4:3 · 3:4 · 3:2 · 2:3 · 21:9 · 9:21 · Default: auto
image_urlsYesPhotos to edit or combine. Say in the prompt what each one adds.
promptYesSay what to change and what must stay the same.
resolutionNoOutput size. Bigger sizes look sharper and cost more. 1k · Default: 1k
seedNoReuse the same number to get a repeatable result. ≥ 0 · ≤ 2147483647

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.

OptionCredits per image≈ USD
Standard17.31$0.17

Each task is rounded up to whole credits, so one run at the lowest tier costs 18 credits per image ($0.18).

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

Use cases

Product scenes

Move a packshot into a styled setting and add a label or a headline.

Mood and weather variations

Show one clothed portrait at dusk, in rain or under neon for a client choosing a direction.

Scenery and everyday images

Change the time of day, the season or the background of a landscape or street scene.

Prompt guide & pro tips

Say what stays

After the change, list the face, outfit and pose that must remain the same.

Number your sources

Write image 1 and image 2 in the prompt so each source has a clear role.

Choose auto to keep the framing

With auto the result follows the size of your first source. Pick a fixed shape only when you want to reframe.

Allow one to two minutes

Edits took 45 to 120 seconds in our tests.

API quick start

Call the FLUX.2 Flex 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-flex/edit 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-flex/edit",
  "input": {
    "prompt": "A ceramic teapot on a linen cloth, soft window light, muted palette",
    "image_urls": [
      "https://media.popnow.ai/influencer/examples/marco.webp"
    ],
    "aspect_ratio": "auto",
    "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 Flex API questions

How much does the FLUX.2 Flex API cost?

FLUX.2 Flex starts at 18 credits ($0.18) per image with Edit Image, its cheapest task. Credits are the same as on the website (1 credit = $0.01), new accounts get 30 free credits, and failed tasks are refunded.

What is the model name for FLUX.2 Flex in the API?

Put black-forest-labs/flux-2-flex/text-to-image for Create Image; black-forest-labs/flux-2-flex/edit for Edit Image in the model field of POST /jobs/createTask.

What is FLUX.2 [flex] best at?

Lettering and layout. In our tests a movie poster with a title, a tagline and a release line, an album cover with a script title, and a tea-tin label all came back with every quoted line spelled as written.

Do hex colour codes work?

Mostly. A code next to a large object or the colour grade is followed closely; on a small line of lettering the shade can shift. In our poster test the release line was asked for in a strong red and came back as a lighter salmon.

Can I tune steps or guidance?

No. Those settings are not offered here. You control the result with the prompt, the aspect ratio, the size tier and the seed.

Why does editing stop at 1k?

Edits with several source images at 2k kept failing in our tests, so editing is offered at 1k only. Text to image offers both 1k and 2k.

FLUX.2 [flex] or another FLUX.2 model?

Pick flex when the picture is mostly about type and layout. The other FLUX.2 models trade differently between speed, realism and openness; compare them on the FLUX.2 family pages.

What are the limits of the FLUX.2 Flex API?

Resolutions: 1K; Aspect ratios: auto · 1:1 · 16:9 · 9:16 · 4:3 · 3:4 +4; Reference images: 3; Prompt length (characters): 5,000; Largest upload: 10 MB. Requests outside these limits are rejected before anything is charged.

Can I try FLUX.2 Flex without writing code?

Yes. The Playground runs FLUX.2 Flex on your PopNow credits, needs no API key, and shows the matching code for every run.

All FLUX models

FLUX.2 Pro is quicker and cheaper for photographic work with lighter text.

More about FLUX.2 Flex