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POST
/
v3
/
async
/
flux-2-flex
Flux 2 Flex Image Gen
curl --request POST \
  --url https://api.novita.ai/v3/async/flux-2-flex \
  --header 'Authorization: <authorization>' \
  --header 'Content-Type: <content-type>' \
  --data '
{
  "seed": 123,
  "size": "<string>",
  "images": [
    {}
  ],
  "prompt": "<string>"
}
'
{
  "task_id": "<string>"
}
FLUX.2 [flex] from Black Forest Labs delivers fast, flexible text-to-image generation with enhanced realism, sharper text rendering, and built-in editing for rapid iteration: a ready-to-use REST inference API, best performance, no cold starts, and affordable pricing.
This is an asynchronous API; only the task_id will be returned. You should use the task_id to request the Task Result API to retrieve the video generation results.

​
Request Headers

​
Content-Type
string
required
Supports: application/json
​
Authorization
string
required
Bearer authentication format, for example: Bearer {{API Key}}.

​
Request Body

​
seed
integer
Random seed for generation. -1 means use a random seed. Range: -1 to 2147483647Value range: [-1, 2147483647]
​
size
string
Pixel size (width*height) of the output media. Each dimension ranges from 256 to 1536 pixels
​
images
array
A list of input image URLs for editing. Up to 3 images are supportedArray length: 1 - 3
​
prompt
string
required
A text prompt describing the expected editing effect for the image

​
Response

​
task_id
string
required
Use the task_id to request the Task Result API to retrieve the generated outputs.
Last modified on June 10, 2026