Claude

fal-aiflux-2-pro

Inference

Commercial use

Partner

Text-to-image generation with FLUX.2 [pro] from Black Forest Labs. Optimized for maximum quality, exceptional photorealism and artistic images.

Learn more about Flux 2 Pro

Inference

Commercial use

Partner

Playground API

API

1. Calling the API#

Install the client#

The client provides a convenient way to interact with the model API.

npm install --save @fal-ai/client

Migrate to @fal-ai/client

The @fal-ai/serverless-client package has been deprecated in favor of @fal-ai/client. Install the new package and update your imports — see client setup.

Setup your API Key#

Set FAL_KEY as an environment variable in your runtime.

export FAL_KEY="YOUR_API_KEY"

Submit a request#

The client API handles the API submit protocol. It will handle the request status updates and return the result when the request is completed.

import { fal } from "@fal-ai/client";

const result = await fal.subscribe("fal-ai/flux-2-pro/edit", {
  input: {
    prompt: "Place realistic flames emerging from the top of the coffee cup, dancing above the rim",
    image_urls: ["https://storage.googleapis.com/falserverless/example_inputs/flux2_pro_edit_input.png"]
  },
  logs: true,
  onQueueUpdate: (update) => {
    if (update.status === "IN_PROGRESS") {
      update.logs.map((log) => log.message).forEach(console.log);
    }
  },
});
console.log(result.data);
console.log(result.requestId);

2. Authentication#

The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.

API Key#

In an environment where you cannot set environment variables, you can configure the API key manually on the client.

import { fal } from "@fal-ai/client";

fal.config({
  credentials: "YOUR_FAL_KEY"
});

Protect your API Key

When running code on the client-side (e.g. in a browser, mobile app or GUI applications), make sure to not expose your FAL_KEY. Instead, use a server-side proxy to make requests to the API. For more information, check out our server-side integration guide.

3. Queue#

Long-running requests

For long-running requests, such as training jobs or models with slower inference times, it is recommended to check the Queue status and rely on Webhooks instead of blocking while waiting for the result.

Submit a request#

The client API provides a convenient way to submit requests to the model.

import { fal } from "@fal-ai/client";

const { request_id } = await fal.queue.submit("fal-ai/flux-2-pro/edit", {
  input: {
    prompt: "Place realistic flames emerging from the top of the coffee cup, dancing above the rim",
    image_urls: ["https://storage.googleapis.com/falserverless/example_inputs/flux2_pro_edit_input.png"]
  },
  webhookUrl: "https://optional.webhook.url/for/results",
});

Fetch request status#

You can fetch the status of a request to check if it is completed or still in progress.

import { fal } from "@fal-ai/client";

const status = await fal.queue.status("fal-ai/flux-2-pro/edit", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
  logs: true,
});

Get the result#

Once the request is completed, you can fetch the result. See the Output Schema for the expected result format.

import { fal } from "@fal-ai/client";

const result = await fal.queue.result("fal-ai/flux-2-pro/edit", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
});
console.log(result.data);
console.log(result.requestId);

4. Files#

Some attributes in the API accept file URLs as input. Whenever that's the case you can pass your own URL or a Base64 data URI.

Data URI (base64)#

You can pass a Base64 data URI as a file input. The API will handle the file decoding for you. Keep in mind that for large files, this alternative although convenient can impact the request performance.

Hosted files (URL)#

You can also pass your own URLs as long as they are publicly accessible. Be aware that some hosts might block cross-site requests, rate-limit, or consider the request as a bot.

Uploading files#

We provide a convenient file storage that allows you to upload files and use them in your requests. You can upload files using the client API and use the returned URL in your requests.

import { fal } from "@fal-ai/client";

const file = new File(["Hello, World!"], "hello.txt", { type: "text/plain" });
const url = await fal.storage.upload(file);

Auto uploads

The client will auto-upload the file for you if you pass a binary object (e.g. File, Data).

Read more about file handling in our file upload guide.

5. Schema#

Input#

prompt string* required

The prompt to generate an image from.

image_size ImageSize | Enum

The size of the generated image. If auto, the size will be determined by the model. Default value: auto

Possible enum values: auto, square_hd, square, portrait_4_3, portrait_16_9, landscape_4_3, landscape_16_9

Note: For custom image sizes, you can pass the width and height as an object:

"image_size": {
  "width": 1280,
  "height": 720
}

seed integer

The seed to use for the generation.

safety_tolerance SafetyToleranceEnum

API only

The safety tolerance level for the generated image. 1 being the most strict and 5 being the most permissive. Default value: "2"

Possible enum values: 1, 2, 3, 4, 5

Note: This property is only available through API calls.

enable_safety_checker boolean

Whether to enable the safety checker. Disabling it requires account authorization; unauthorized requests are always checked. Default value: true

output_format OutputFormatEnum

The format of the generated image. Default value: "jpeg"

Possible enum values: jpeg, png

sync_mode boolean

If True, the media will be returned as a data URI and the output data won't be available in the request history.

image_urls list<string>* required

List of URLs of input images for editing

{
  "prompt": "Place realistic flames emerging from the top of the coffee cup, dancing above the rim",
  "image_size": "auto",
  "safety_tolerance": "2",
  "enable_safety_checker": true,
  "output_format": "jpeg",
  "image_urls": [
    "https://storage.googleapis.com/falserverless/example_inputs/flux2_pro_edit_input.png"
  ]
}

Output#

images list<ImageFile>* required

The generated images.

seed integer* required

The seed used for the generation.

{
  "images": [
    {
      "url": "https://storage.googleapis.com/falserverless/example_outputs/flux2_pro_edit_output.png"
    }
  ]
}

Other types#

ImageSize#

width integer

The width of the generated image. Default value: 512

height integer

The height of the generated image. Default value: 512

ImageFile#

url string* required

The URL where the file can be downloaded from.

content_type string

The mime type of the file.

file_name string

The name of the file. It will be auto-generated if not provided.

file_size integer

The size of the file in bytes.

width integer

The width of the image

height integer

The height of the image

Related Models

API

1. Calling the API#

Install the client#

The client provides a convenient way to interact with the model API.

npm install --save @fal-ai/client

Migrate to @fal-ai/client

The @fal-ai/serverless-client package has been deprecated in favor of @fal-ai/client. Install the new package and update your imports — see client setup.

Setup your API Key#

Set FAL_KEY as an environment variable in your runtime.

export FAL_KEY="YOUR_API_KEY"

Submit a request#

The client API handles the API submit protocol. It will handle the request status updates and return the result when the request is completed.

import { fal } from "@fal-ai/client";

const result = await fal.subscribe("fal-ai/flux-2-pro/edit", {
  input: {
    prompt: "Place realistic flames emerging from the top of the coffee cup, dancing above the rim",
    image_urls: ["https://storage.googleapis.com/falserverless/example_inputs/flux2_pro_edit_input.png"]
  },
  logs: true,
  onQueueUpdate: (update) => {
    if (update.status === "IN_PROGRESS") {
      update.logs.map((log) => log.message).forEach(console.log);
    }
  },
});
console.log(result.data);
console.log(result.requestId);

2. Authentication#

The API uses an API Key for authentication. It is recommended you set the FAL_KEY environment variable in your runtime when possible.

API Key#

In an environment where you cannot set environment variables, you can configure the API key manually on the client.

import { fal } from "@fal-ai/client";

fal.config({
  credentials: "YOUR_FAL_KEY"
});

Protect your API Key

3. Queue#

Long-running requests

Submit a request#

The client API provides a convenient way to submit requests to the model.

import { fal } from "@fal-ai/client";

const { request_id } = await fal.queue.submit("fal-ai/flux-2-pro/edit", {
  input: {
    prompt: "Place realistic flames emerging from the top of the coffee cup, dancing above the rim",
    image_urls: ["https://storage.googleapis.com/falserverless/example_inputs/flux2_pro_edit_input.png"]
  },
  webhookUrl: "https://optional.webhook.url/for/results",
});

Fetch request status#

You can fetch the status of a request to check if it is completed or still in progress.

import { fal } from "@fal-ai/client";

const status = await fal.queue.status("fal-ai/flux-2-pro/edit", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b",
  logs: true,
});

Get the result#

Once the request is completed, you can fetch the result. See the Output Schema for the expected result format.

import { fal } from "@fal-ai/client";

const result = await fal.queue.result("fal-ai/flux-2-pro/edit", {
  requestId: "764cabcf-b745-4b3e-ae38-1200304cf45b"
});
console.log(result.data);
console.log(result.requestId);

4. Files#

Some attributes in the API accept file URLs as input. Whenever that's the case you can pass your own URL or a Base64 data URI.

Data URI (base64)#

Hosted files (URL)#

You can also pass your own URLs as long as they are publicly accessible. Be aware that some hosts might block cross-site requests, rate-limit, or consider the request as a bot.

Uploading files#

We provide a convenient file storage that allows you to upload files and use them in your requests. You can upload files using the client API and use the returned URL in your requests.

import { fal } from "@fal-ai/client";

const file = new File(["Hello, World!"], "hello.txt", { type: "text/plain" });
const url = await fal.storage.upload(file);

Auto uploads

The client will auto-upload the file for you if you pass a binary object (e.g. File, Data).

Read more about file handling in our file upload guide.

5. Schema#

Input#

prompt string* required

The prompt to generate an image from.

image_size ImageSize | Enum

The size of the generated image. If auto, the size will be determined by the model. Default value: auto

Possible enum values: auto, square_hd, square, portrait_4_3, portrait_16_9, landscape_4_3, landscape_16_9

Note: For custom image sizes, you can pass the width and height as an object:

"image_size": {
  "width": 1280,
  "height": 720
}

seed integer

The seed to use for the generation.

safety_tolerance SafetyToleranceEnum

API only

The safety tolerance level for the generated image. 1 being the most strict and 5 being the most permissive. Default value: "2"

Possible enum values: 1, 2, 3, 4, 5

Note: This property is only available through API calls.

enable_safety_checker boolean

Whether to enable the safety checker. Disabling it requires account authorization; unauthorized requests are always checked. Default value: true

output_format OutputFormatEnum

The format of the generated image. Default value: "jpeg"

Possible enum values: jpeg, png

sync_mode boolean

If True, the media will be returned as a data URI and the output data won't be available in the request history.

image_urls list<string>* required

List of URLs of input images for editing

{
  "prompt": "Place realistic flames emerging from the top of the coffee cup, dancing above the rim",
  "image_size": "auto",
  "safety_tolerance": "2",
  "enable_safety_checker": true,
  "output_format": "jpeg",
  "image_urls": [
    "https://storage.googleapis.com/falserverless/example_inputs/flux2_pro_edit_input.png"
  ]
}

Output#

images list<ImageFile>* required

The generated images.

seed integer* required

The seed used for the generation.

{
  "images": [
    {
      "url": "https://storage.googleapis.com/falserverless/example_outputs/flux2_pro_edit_output.png"
    }
  ]
}

Other types#

ImageSize#

width integer

The width of the generated image. Default value: 512

height integer

The height of the generated image. Default value: 512

ImageFile#

url string* required

The URL where the file can be downloaded from.

content_type string

The mime type of the file.

file_name string

The name of the file. It will be auto-generated if not provided.

file_size integer

The size of the file in bytes.

width integer

The width of the image

height integer

The height of the image

Related Models

FLUX 2 Pro Edit Image to Image API Docs | fal