FLUX.1 [dev]

Open-weight text-to-image model with advanced prompt adherence, anatomically accurate details, and powerful tools for inpainting, outpainting, and structural…

Try FLUX.1 [dev] in the Workbench

Run this model interactively, tune parameters, and compare outputs.

Model ID: flux-1-dev

black-forest-labs/FLUX.1-dev is a 12 billion parameter image generation model (rectified flow transformer, guidance-distilled) designed for non-commercial, research, and personal use.

It excels in generating high-quality, diverse images from text prompts, with strong prompt adherence and competitive performance on challenging details such as hands and faces. Its open weights and efficiency make it particularly valuable for researchers and developers who need transparency, adaptability, and the ability to fine-tune for specialized domains.

Some other noteworthy features of black-forest-labs/FLUX.1-dev include advanced control tools—such as inpainting, outpainting, structural guidance (depth and edge conditioning), and image remixing—enabling precise editing and re-creation of both real and generated images for research and creative workflows.

Metric	Value
Parameter Count	12 billion
Mixture of Experts	No
Context Length	Unknown
Multilingual	No
Quantized*	No

*Quantization is specific to the inference provider and the model may be offered with different quantization levels by other providers.

Example request

Use the Workbench as a request builder: configure parameters for this model in the UI, then open the API tab to copy the exact cURL or Python call.

Sync

See the image generation reference for more details.

Minimal

cURL

curl -X POST https://hub.oxen.ai/api/ai/images/generate \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "flux-1-dev",
  "prompt": "A beautiful landscape painting of a serene lake with mountains in the background"
}'

import os
import requests

response = requests.post(
    "https://hub.oxen.ai/api/ai/images/generate",
    headers={
        "Content-Type": "application/json",
        "Authorization": f"Bearer {os.environ['OXEN_API_KEY']}",
    },
    json={
        "model": "flux-1-dev",
        "prompt": "A beautiful landscape painting of a serene lake with mountains in the background"
    },
)
response.raise_for_status()
print(response.json())

All parameters

cURL

curl -X POST https://hub.oxen.ai/api/ai/images/generate \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "flux-1-dev",
  "prompt": "A beautiful landscape painting of a serene lake with mountains in the background",
  "negative_prompt": " ",
  "aspect_ratio": "16:9",
  "image_size": "optimize_for_quality",
  "num_inference_steps": 30,
  "guidance": 3,
  "output_format": "webp",
  "output_quality": 80,
  "disable_safety_checker": false
}'

import os
import requests

response = requests.post(
    "https://hub.oxen.ai/api/ai/images/generate",
    headers={
        "Content-Type": "application/json",
        "Authorization": f"Bearer {os.environ['OXEN_API_KEY']}",
    },
    json={
        "model": "flux-1-dev",
        "prompt": "A beautiful landscape painting of a serene lake with mountains in the background",
        "negative_prompt": " ",
        "aspect_ratio": "16:9",
        "image_size": "optimize_for_quality",
        "num_inference_steps": 30,
        "guidance": 3,
        "output_format": "webp",
        "output_quality": 80,
        "disable_safety_checker": false
    },
)
response.raise_for_status()
print(response.json())

Async

See the async queue reference for more details.

Minimal

cURL

# Enqueue, capture the generation id.
GEN_ID=$(curl -s -X POST https://hub.oxen.ai/api/ai/queue \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "flux-1-dev",
  "prompt": "A beautiful landscape painting of a serene lake with mountains in the background"
}' | jq -r '.generations[0].generation_id')

# Poll the single generation until it 404s (terminal state).
while curl -s -o /dev/null -w "%{http_code}" \
    -H "Authorization: Bearer $OXEN_API_KEY" \
    "https://hub.oxen.ai/api/ai/queue/$GEN_ID" | grep -q "^200$"; do
  sleep 5
done
echo "Done. See the 'Async with SSE' tab to receive the result URL."

import os
import time
import requests

HEADERS = {
    "Content-Type": "application/json",
    "Authorization": f"Bearer {os.environ['OXEN_API_KEY']}",
}

enqueue = requests.post(
    "https://hub.oxen.ai/api/ai/queue",
    headers=HEADERS,
    json={
        "model": "flux-1-dev",
        "prompt": "A beautiful landscape painting of a serene lake with mountains in the background"
    },
)
enqueue.raise_for_status()
generation_id = enqueue.json()["generations"][0]["generation_id"]

while True:
    resp = requests.get(
        f"https://hub.oxen.ai/api/ai/queue/{generation_id}",
        headers=HEADERS,
    )
    if resp.status_code == 404:
        break
    time.sleep(5)
print("Done. See the 'Async with SSE' tab to receive the result URL.")

All parameters

cURL

# Enqueue, capture the generation id.
GEN_ID=$(curl -s -X POST https://hub.oxen.ai/api/ai/queue \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "flux-1-dev",
  "prompt": "A beautiful landscape painting of a serene lake with mountains in the background",
  "negative_prompt": " ",
  "aspect_ratio": "16:9",
  "image_size": "optimize_for_quality",
  "num_inference_steps": 30,
  "guidance": 3,
  "output_format": "webp",
  "output_quality": 80,
  "disable_safety_checker": false
}' | jq -r '.generations[0].generation_id')

# Poll the single generation until it 404s (terminal state).
while curl -s -o /dev/null -w "%{http_code}" \
    -H "Authorization: Bearer $OXEN_API_KEY" \
    "https://hub.oxen.ai/api/ai/queue/$GEN_ID" | grep -q "^200$"; do
  sleep 5
done
echo "Done. See the 'Async with SSE' tab to receive the result URL."

import os
import time
import requests

HEADERS = {
    "Content-Type": "application/json",
    "Authorization": f"Bearer {os.environ['OXEN_API_KEY']}",
}

enqueue = requests.post(
    "https://hub.oxen.ai/api/ai/queue",
    headers=HEADERS,
    json={
        "model": "flux-1-dev",
        "prompt": "A beautiful landscape painting of a serene lake with mountains in the background",
        "negative_prompt": " ",
        "aspect_ratio": "16:9",
        "image_size": "optimize_for_quality",
        "num_inference_steps": 30,
        "guidance": 3,
        "output_format": "webp",
        "output_quality": 80,
        "disable_safety_checker": false
    },
)
enqueue.raise_for_status()
generation_id = enqueue.json()["generations"][0]["generation_id"]

while True:
    resp = requests.get(
        f"https://hub.oxen.ai/api/ai/queue/{generation_id}",
        headers=HEADERS,
    )
    if resp.status_code == 404:
        break
    time.sleep(5)
print("Done. See the 'Async with SSE' tab to receive the result URL.")

Async with SSE

See the async queue reference for more details.

Minimal

cURL

# Enqueue, capture the generation id.
GEN_ID=$(curl -s -X POST https://hub.oxen.ai/api/ai/queue \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "flux-1-dev",
  "prompt": "A beautiful landscape painting of a serene lake with mountains in the background"
}' | jq -r '.generations[0].generation_id')

# Stream the SSE channel, grab the data line that follows a
# media_generation_completed event for our id, and pretty-print it.
curl -sN -H "Authorization: Bearer $OXEN_API_KEY" https://hub.oxen.ai/api/events \
  | awk -v id="$GEN_ID" '
    /^event: media_generation_completed$/ { expect=1; next }
    /^data: / && expect {
      payload = substr($0, 7)
      if (index(payload, "\"generation_id\":\"" id "\"")) { print payload; exit }
      expect = 0
    }
  ' | jq .

import json
import os
import requests

API_KEY = os.environ["OXEN_API_KEY"]
AUTH = {"Authorization": f"Bearer {API_KEY}"}

enqueue = requests.post(
    "https://hub.oxen.ai/api/ai/queue",
    headers={**AUTH, "Content-Type": "application/json"},
    json={
        "model": "flux-1-dev",
        "prompt": "A beautiful landscape painting of a serene lake with mountains in the background"
    },
)
enqueue.raise_for_status()
generation_id = enqueue.json()["generations"][0]["generation_id"]

with requests.get(
    "https://hub.oxen.ai/api/events",
    headers=AUTH,
    stream=True,
) as stream:
    event_name = None
    for line in stream.iter_lines(decode_unicode=True):
        if line.startswith("event: "):
            event_name = line.removeprefix("event: ")
        elif line.startswith("data: ") and event_name == "media_generation_completed":
            payload = json.loads(line.removeprefix("data: "))
            if payload.get("generation_id") == generation_id:
                print(payload)
                break

All parameters

cURL

# Enqueue, capture the generation id.
GEN_ID=$(curl -s -X POST https://hub.oxen.ai/api/ai/queue \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $OXEN_API_KEY" \
  -d '{
  "model": "flux-1-dev",
  "prompt": "A beautiful landscape painting of a serene lake with mountains in the background",
  "negative_prompt": " ",
  "aspect_ratio": "16:9",
  "image_size": "optimize_for_quality",
  "num_inference_steps": 30,
  "guidance": 3,
  "output_format": "webp",
  "output_quality": 80,
  "disable_safety_checker": false
}' | jq -r '.generations[0].generation_id')

# Stream the SSE channel, grab the data line that follows a
# media_generation_completed event for our id, and pretty-print it.
curl -sN -H "Authorization: Bearer $OXEN_API_KEY" https://hub.oxen.ai/api/events \
  | awk -v id="$GEN_ID" '
    /^event: media_generation_completed$/ { expect=1; next }
    /^data: / && expect {
      payload = substr($0, 7)
      if (index(payload, "\"generation_id\":\"" id "\"")) { print payload; exit }
      expect = 0
    }
  ' | jq .

import json
import os
import requests

API_KEY = os.environ["OXEN_API_KEY"]
AUTH = {"Authorization": f"Bearer {API_KEY}"}

enqueue = requests.post(
    "https://hub.oxen.ai/api/ai/queue",
    headers={**AUTH, "Content-Type": "application/json"},
    json={
        "model": "flux-1-dev",
        "prompt": "A beautiful landscape painting of a serene lake with mountains in the background",
        "negative_prompt": " ",
        "aspect_ratio": "16:9",
        "image_size": "optimize_for_quality",
        "num_inference_steps": 30,
        "guidance": 3,
        "output_format": "webp",
        "output_quality": 80,
        "disable_safety_checker": false
    },
)
enqueue.raise_for_status()
generation_id = enqueue.json()["generations"][0]["generation_id"]

with requests.get(
    "https://hub.oxen.ai/api/events",
    headers=AUTH,
    stream=True,
) as stream:
    event_name = None
    for line in stream.iter_lines(decode_unicode=True):
        if line.startswith("event: "):
            event_name = line.removeprefix("event: ")
        elif line.startswith("data: ") and event_name == "media_generation_completed":
            payload = json.loads(line.removeprefix("data: "))
            if payload.get("generation_id") == generation_id:
                print(payload)
                break

Fetch model details

The models endpoint returns the full model object, including its json_request_schema.

curl -H "Authorization: Bearer $OXEN_API_KEY" https://hub.oxen.ai/api/ai/models/flux-1-dev

Request parameters

Required parameters

Field	Type	Default	Description
prompt	string	"A beautiful landscape painting of a serene lake with mountains in the background"	Prompt for generated image

Optional parameters

Field	Type	Default	Description
negative_prompt	string	" "	Negative prompt for generated image
aspect_ratio	string	"16:9"	Aspect ratio for the generated image One of: 1:1, 16:9, 9:16, 4:3, 3:4, 3:2, 2:3.
image_size	string	"optimize_for_quality"	Image size for the generated image One of: optimize_for_quality, optimize_for_speed.
num_inference_steps	integer	30	Number of denoising steps. Recommended range is 28-50, and lower number of steps produce lower quality outputs, faster. Range: 1 – 50.
guidance	number	3	Guidance for generated image. Lower values can give more realistic images. Good values to try are 2, 2.5, 3 and 3.5 Range: 0 – 10.
seed	integer	—	Random seed. Set for reproducible generation
output_format	string	"webp"	Format of the output images One of: webp, jpg, png.
output_quality	integer	80	Quality when saving the output images, from 0 to 100. 100 is best quality, 0 is lowest quality. Not relevant for .png outputs Range: 0 – 100.
disable_safety_checker	boolean	false	Disable safety checker for generated images.