Black Forest Labs

FLUX 1.1 Pro

flux-1.1-pro

Black Forest Labs' flagship text-to-image model, roughly 6 times faster than Flux.1 Pro with better prompt adherence, ideal for image generation at scale

flux-1.1-pro

Try flux-1.1-pro

Input

Showcases

View all showcases

Output

image

Fill in the parameters and run — results show up here.

Pricing

flux-1.1-pro per image

Unit Price	$0.050

Overview

flux-1.1-pro is a production-oriented text-to-image and image-to-image model from Black Forest Labs, which developers can call through the unified HiAPI.ai interface. It supports generating images directly from text prompts, and can also perform image-conditioned generation by attaching a reference image URL; its prompt adherence is strong, making it suitable for business workflows that require stable output of high-quality images. Aspect ratios cover common specifications such as 1:1, 16:9, 3:2, 4:5, and 9:16, and custom sizes are also supported. Output format and quality are adjustable, making it easy to integrate into batch image generation and automated production pipelines.

Key Highlights

Dual text-to-image and image-to-image modes — the same interface supports both pure prompt-based generation and image-conditioned generation by passing in a reference image URL, reducing the need to switch between multiple models.
Reproducible generation control — supports a fixed seed, so repeated calls yield consistent results, which is convenient for regression testing and reproducing batch tasks.
Output parameters adjustable as needed — offers aspect ratio, custom size, webp/jpg/png format, and output quality options to suit different downstream uses.
Designed for production workflows — the parameter structure is complete, making it suitable for integration into automated batch image generation and stable delivery business processes.

Capabilities

Text-to-image generation: generates images directly with prompt as the core input, suitable for creative work and asset production starting without source material.

Reference-image-conditioned generation: pass in a jpeg, png, gif, or webp reference image URL via image_prompt to generate based on existing visuals.

Canvas and size control: includes multiple common aspect ratios; when custom is selected, width and height can be set from 256 to 1440 pixels and are aligned to multiples of 32.

Output format and quality: choose webp, jpg, or png output and set output quality from 0 to 100; png output is not affected by the quality parameter.

Reproducible generation and detail adjustment: a fixed seed reproduces results, prompt_upsampling can automatically rewrite prompts, and safety_tolerance can adjust how permissive content filtering is.

Use Cases

Batch image generation for marketing and advertising assets — operations and marketing teams input campaign copy and produce promotional images in multiple aspect ratios for ad channels and landing pages.
Product visualization scene images — e-commerce teams use product descriptions or reference images as input to generate product scene images for detail pages and presentation materials.
Illustration production for content creators — creators input prompts based on article topics and produce illustrations with a consistent style for article content and social media publishing.
Visual presentation for design prototypes — designers use concept descriptions or reference images as input to quickly produce visual drafts for proposal discussions and prototype direction confirmation.
Image generation nodes in automated workflows — engineering teams integrate the interface into pipelines to stably produce images with fixed parameters and seeds for large-scale content production.

Limitations and Selection Advice

It only outputs static images and does not support video or other modalities; generation results depend on prompt quality, and complex or specific requirements need multiple rounds of tuning. The maximum width and height is 1440 pixels, custom sizes are aligned to 32-pixel multiples, and oversized requirements need to be handled separately. Output quality is mainly adjusted for webp/jpg; the quality parameter does not take effect for png. Lowering the safety tolerance may affect the pass rate of image generation. If a task requires video generation or batch control beyond the scope of a single image, a model with the corresponding modality should be used instead.

Frequently asked questions

View all FAQs →

What is FLUX1.1 [pro] best for?

Generate polished photography, architecture, food, nature, and commercial visuals with custom sizing and prompt upsampling controls.
Does FLUX1.1 [pro] accept reference images?

No. This route is text-to-image only.
Which output settings are supported?

The page exposes Custom width / height and Custom, 1:1, 16:9, 9:16; use the Playground contract for the final available set.
How is FLUX1.1 [pro] billed?

Billing is per successful generated image. Resolution or quality differences, when present, are reflected by the live page price.

Create a generation task

POST https://api.hiapi.ai/v1/tasks

Headers

AuthorizationstringRequired

Account API key. Required on every request. Example: Bearer YOUR_HIAPI_API_KEY. Get your API key

Content-TypestringOptional

The request body is always parsed as JSON; when sent, only application/json (optionally with charset) is accepted — any other value returns 415. Example: application/json.

Idempotency-KeystringOptional

Idempotency key, up to 255 bytes. Retries with the same key from the same account create the task only once; replays return the original taskId.

Idempotency key

On network timeouts or client retries, the same key creates the task only once — no double charges (scope: the API key's account). Use a business-unique identifier as the key (e.g. "order-42"); replays return the original taskId, and keys expire 24 hours after the first request. See the Unified Async API overview for the full scenario matrix.

Body

modelstringRequired

Current fixed value: flux-1.1-pro

routestringOptional

Current fixed value: default

inputobjectRequired

Business parameters for flux-1.1-pro and route default — see the parameter table below.

seedintegerOptional

Random seed used to produce reproducible results; when the same seed and other parameters are identical, the same generation can be reproduced.

widthintegerOptionalmin 256max 1440

Custom image width, used only when aspect_ratio is custom; the value is rounded to the nearest multiple of 32.

heightintegerOptionalmin 256max 1440

Custom image height, used only when aspect_ratio is custom; the value is rounded to the nearest multiple of 32.

promptstringRequired

The text prompt used for image generation.

aspect_ratiostringOptionalDefault: "1:1"

The aspect ratio of the generated image, default 1:1.

Options:custom1:116:93:22:34:55:49:16

Show all (2)

3:44:3

image_promptstringOptional

Optional reference image URL; the format must be jpeg, png, gif, or webp.

output_formatstringOptionalDefault: "webp"

The format of the output image, default webp.

Options:webpjpgpng

output_qualityintegerOptionalDefault: 80min 0max 100

The quality used when saving the output image, an integer from 0 to 100, default 80; has no effect on png output.

safety_toleranceintegerOptionalDefault: 2min 1max 6

Safety tolerance, ranging from 1 to 6, where 1 is the strictest and 6 is the most permissive, default 2.

prompt_upsamplingbooleanOptionalDefault: false

Whether to automatically rewrite the prompt to increase generation creativity, default false.

callbackobjectOptional

Terminal-state notification config. When omitted, no callback is delivered — poll the task yourself. See the callback note below.

Callbacks (Webhook)

Provide callback.url when creating a task and HiAPI POSTs to your service once the task reaches a terminal state — no polling needed. The callback payload mirrors the task detail structure; signature verification, delivery retries and idempotency are documented on the Unified Async API overview page.

urlstringRequired

Required when callback is present. A POST is sent to this URL once the task reaches a terminal state; must be a valid http(s) URL.

whenstringOptionalDefault: "final"

Only final is supported today — notified on both success and fail.

Options:final

storagestringOptionalDefault: "temp"

Artifact storage tier: temp (default, retained about 7 days) or persistent (long-term, billed by size). Insufficient balance or exceeding the storage cap silently downgrades to temp; the effective tier is shown in the task detail response.

Options:temppersistent

Request examples

# Submit an async task; returns a taskId immediately (no waiting for generation)
curl -X POST "https://api.hiapi.ai/v1/tasks" \
  -H "Authorization: Bearer $HIAPI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "flux-1.1-pro",
  "input": {
    "prompt": "…",
    "aspect_ratio": "1:1",
    "output_format": "webp",
    "output_quality": 80,
    "safety_tolerance": 2,
    "prompt_upsampling": false
  }
}'

const res = await fetch("https://api.hiapi.ai/v1/tasks", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.HIAPI_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "flux-1.1-pro",
    input: {
      "prompt": "…",
      "aspect_ratio": "1:1",
      "output_format": "webp",
      "output_quality": 80,
      "safety_tolerance": 2,
      "prompt_upsampling": false
    }
  }),
});
const task = await res.json();
// { code: 200, message: "success", data: { taskId } }

import os, requests

res = requests.post(
    "https://api.hiapi.ai/v1/tasks",
    headers={"Authorization": f"Bearer {os.environ['HIAPI_API_KEY']}"},
    json={
        "model": "flux-1.1-pro",
        "input": {
          "prompt": "…",
          "aspect_ratio": "1:1",
          "output_format": "webp",
          "output_quality": 80,
          "safety_tolerance": 2,
          "prompt_upsampling": False
        }
    },
)
print(res.json())  # { code, message, data: { taskId } }

200 OK

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "tk-hiapi-01HZTQ8BX2N3GM3YFK4Z9D7VQR"
  }
}

400 Bad Request

{
  "code": 400,
  "message": "invalid request",
  "data": null,
  "error_code": "INVALID_REQUEST"
}

Get task detail

GET https://api.hiapi.ai/v1/tasks/:id

Response fields

taskIdstringRequired

Task ID, always prefixed with tk-hiapi-.

modelstringRequired

Resolved full model name. Tasks submitted with the route parameter return base@route (e.g. gpt-image-2/text-to-image@ext); otherwise identical to the name passed at creation.

routestringOptional

Present only when the task was submitted with an explicit route parameter; echoes the submitted value.

statusstringRequired

Task status.

Status values

queued Queued, not started yet. handling Being processed. archiving Processing finished, artifacts being prepared. success Terminal: completed, artifacts available (output returned). fail Terminal: failed (error returned). After submission, check status: success and fail are terminal, everything else is non-terminal. Poll every 1–3 seconds until terminal. On success, download artifacts from output[].url and transfer them before expireAt; pass storage: "persistent" at creation time when long-term retention is needed.

creatednumberRequired

Task creation time (Unix seconds).

completednumberRequired

Unix seconds when the task reached a terminal state; fixed to 0 while not terminal.

outputarrayOptional

Present only when status == success. Artifact list — always an array; a single task may return multiple types at once (e.g. video + first_frame).

Array [ object ]

Array items

urlstringRequired

Artifact URL, directly downloadable.

typestringRequired

Current possible values: video, image, audio, first_frame, last_frame, thumbnail; more may be added later.

expireAtnumberRequired

Unix seconds until which the artifact remains accessible; download or transfer before it expires.

errorobjectOptional

Present only when status == fail.

codestringRequired

Business error code.

messagestringRequired

Error description.

Response examples

Success

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "tk-hiapi-01HZTQ8BX2N3GM3YFK4Z9D7VQR",
    "model": "happyhorse-1-0",
    "status": "success",
    "created": 1777282033,
    "completed": 1777282099,
    "output": [
      {
        "url": "https://cdn.hiapi.ai/tasks/.../video.mp4",
        "type": "video",
        "expireAt": 1777886899
      }
    ]
  }
}

Processing (non-terminal)

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "tk-hiapi-...",
    "model": "happyhorse-1-0",
    "status": "archiving",
    "created": 1777282033,
    "completed": 0
  }
}

Failed

{
  "code": 200,
  "message": "success",
  "data": {
    "taskId": "tk-hiapi-...",
    "model": "happyhorse-1-0",
    "status": "fail",
    "created": 1777282033,
    "completed": 1777282099,
    "error": {
      "code": "TASK_FAILED",
      "message": "task failed"
    }
  }
}