Flux 1.1 Pro Ultra

Name: Flux 1.1 Pro Ultra
Brand: Black Forest Labs
SKU: flux-pro-ultra
Price: 0.072 USD
Availability: InStock

Image generationAvailable

by Black Forest Labsflux-pro-ultra

FLUX 1.1 Pro in ultra mode. Up to 4 megapixel images with raw mode for photorealism.

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Price: $0.072/image
Aspect ratios: 1:1, 16:9, 9:16, 3:2, 2:3, 21:9, 9:21
Input → output: Text → Image
Developer: Black Forest Labs
Updated: September 23, 2026

Playground

Try Flux 1.1 Pro Ultra

Input & output

$0.072/image

Prompt

Aspect ratio(optional)

Advanced settings (2)

Output format(optional)

Raw

⌘/Ctrl + Enter

Output

Your image appears here.

This run

$0.072 · 7.2 credits

For accounts without a purchase: runs above 2 credits need a top-up.

New here?

10 free credits ($0.10) when you sign up with Google

Usable 24 hours after sign-up, up to 5 runs per day and at most 2 credits per run. Other sign-in methods start without credits.

Examples

Real outputs from the public examples of this model on Replicate, with the prompt and settings that produced them. They were not generated live on this page.

Open full size
Prompt
a majestic snow-capped mountain peak bathed in a warm glow of the setting sun
Settings
aspect_ratio

3:2
Open full size
Prompt
a close up of a miniature model of a small village nestled amidst a lush, verdant landscape, featuring a winding river and a backdrop of trees and buildings.
Settings
aspect_ratio

3:2
Open full size
Prompt
the serene interior of a cave, where a pool of water is nestled amidst an abundance of greenery. Sunlight filters through the cave opening, casting a soft glow on the surrounding foliage and the tranquil water below
Settings
aspect_ratio

3:2

Example prompts

Examples from the Railwail catalog. They were not generated live on this page.

Photorealistic Portrait
A close-up editorial portrait of an elderly fisherman with deep weathered wrinkles, bright blue eyes, wearing a cable-knit sweater, shot on medium format film with shallow depth of field, natural window light
Architecture
A stunning modern cliffside villa with floor-to-ceiling glass walls overlooking the Mediterranean Sea, infinity pool merging with the horizon, golden hour lighting, architectural photography style
Nature Macro
An extreme macro photograph of morning dew drops on a spider web, each droplet acting as a tiny lens refracting the sunrise behind it, bokeh background of wildflowers, National Geographic quality

About Flux 1.1 Pro Ultra

TL;DRAs of September 23, 2026

Flux 1.1 Pro Ultra is a model by Black Forest Labs in the Image generation category. On Railwail, Flux 1.1 Pro Ultra costs $0.072 per image. Supported aspect ratios: 1:1, 16:9, 9:16, 3:2, 2:3, 21:9, and 9:21.

Background

About Black Forest Labs

Founded 2024 · Freiburg, Germany

Black Forest Labs was founded in August 2024 by Robin Rombach, Patrick Esser, Andreas Blattmann and Dominik Lorenz, the team that created Latent Diffusion at LMU Munich and Stable Diffusion at Stability AI. Headquartered in Freiburg, Germany, the lab raised a $31M seed round led by Andreessen Horowitz and has since released the FLUX.1 family and FLUX 1.1 series. FLUX 1.1 [pro] (released October 2024) and the higher-resolution FLUX 1.1 [pro] Ultra (released November 2024) are the flagship commercial tiers, available only through the Black Forest Labs API and partner platforms such as Replicate, fal.ai and Together AI.

Visit Black Forest Labs

Architecture

Rectified-flow Diffusion Transformer (DiT) with native 4 MP rendering

FLUX 1.1 [pro] Ultra is Black Forest Labs' highest-quality commercial image model, released as an API-only tier in November 2024. It builds on the FLUX 1.1 [pro] backbone — a rectified-flow Diffusion Transformer trained with the flow-matching objective from the SD3 paper (Esser et al. 2024) — but is fine-tuned and architecturally extended to produce up to 4 megapixels (2048x2048 or 1568x2520) natively without tiling or super-resolution. Black Forest Labs reports that Ultra achieves these resolutions with the same speed as standard FLUX 1.1 [pro] thanks to architectural and inference optimisations including grouped attention, FP8 inference and improved noise schedules. A complementary 'Raw' mode is exposed that produces less stylised, more photographic outputs. The model uses T5-XXL plus CLIP-L text encoders, the standard 16x latent VAE and 28-50 flow-matching sampling steps.

Parameters: Undisclosed (substantially larger than 12B FLUX.1 backbone)
Context: 512 tokens

Capabilities

Native 4 MP rendering (up to 2048x2048 or 1568x2520)
State-of-the-art photorealism in the FLUX family
'Raw' mode for unstylised photographic look
Strong typography for an image model
Excellent prompt adherence via T5-XXL
Fast inference (~10-20s per 4MP image)
Available via Black Forest Labs API, Replicate, fal.ai, Together AI
Best for: print-quality marketing, large-format ads, editorial photography, premium creative.

Training & license

Pretrained on a large licensed image-text corpus; fine-tuned at high resolutions for the Ultra tier. Exact data is not disclosed.

License: Proprietary commercial license via Black Forest Labs API and approved partners. Pay-per-image pricing.

Safety testing: API-level safety filters covering CSAM, NCII, IP-protected characters and named living persons. Outputs may carry watermark metadata.

Known limitations

API only, no open weights
Higher per-image cost than dev/schnell tiers
Generation latency higher than 1 MP modes
No fine-tuning for external customers

Research papers

Pricing

Prices in US dollars. Usage is charged from prepaid credits.

Per image	$0.072 per image

1 credit = $0.01

Cost calculator

Price calculator

Runs

Total

$7.20

720 credits

Per run

$0.072 · 7.2 credits

Fixed price per run, known before the run starts.

API

Call Flux 1.1 Pro Ultra with your Railwail API key. Use this model ID in the request:

flux-pro-ultraAPI documentation Get an API key

curl https://railwail.com/api/v1/images/generations \
  -H "Authorization: Bearer $RAILWAIL_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "flux-pro-ultra",
    "prompt": "A lighthouse on a rocky coast at sunset, photorealistic"
  }'

import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["RAILWAIL_API_KEY"],
    base_url="https://railwail.com/api/v1",
)

image = client.images.generate(
    model="flux-pro-ultra",
    prompt="A lighthouse on a rocky coast at sunset, photorealistic",
)

print(image.data[0].url)

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.RAILWAIL_API_KEY,
  baseURL: "https://railwail.com/api/v1",
});

const image = await client.images.generate({
  model: "flux-pro-ultra",
  prompt: "A lighthouse on a rocky coast at sunset, photorealistic"
});

console.log(image.data[0].url);

// npm install railwail
import railwail from "railwail";

const rw = railwail(process.env.RAILWAIL_API_KEY);

const res = await rw.image("flux-pro-ultra", "A lighthouse on a rocky coast at sunset, photorealistic");

console.log(res.data[0].url);

Set your key as RAILWAIL_API_KEYCreate API key

Specifications

Model ID: flux-pro-ultra
Developer: Black Forest Labs
Category: Image generation
Input: Text
Output: Image
Output formats: JPG, PNG
Aspect ratios: 1:1, 16:9, 9:16, 3:2, 2:3, 21:9, 9:21
Billing: Fixed price, known before the run
Model size: Undisclosed (substantially larger than 12B FLUX.1 backbone)
License: Proprietary commercial license via Black Forest Labs API and approved partners. Pay-per-image pricing.
Catalog entry updated: September 23, 2026

Input parameters

Inputs and settings from the model's input schema. The example in the API section shows which of them the API accepts.

ParameterTypeDefaultAllowed values

promptrequired
Type: Text
Default: –
Allowed values: –
raw
Type: Yes/no
Default: false
Allowed values: –
aspect_ratio
Type: Choice
Default: 3:2
Allowed values: 1:1, 16:9, 9:16, 3:2, 2:3, 21:9, or 9:21
output_format
Type: Choice
Default: jpg
Allowed values: jpg or png

Use cases

What it is used for

Print-quality advertising creatives
Editorial and magazine illustration
Premium brand campaigns
Large-format poster and billboard imagery
Hero shots for e-commerce
Stock-photo-grade content

All models in Image generation

Frequently asked questions

What is Flux 1.1 Pro Ultra?

Flux 1.1 Pro Ultra is a model by Black Forest Labs in the Image generation category. On Railwail you can call it with an API key through the Railwail API.

How much does Flux 1.1 Pro Ultra cost on Railwail?

On Railwail, Flux 1.1 Pro Ultra costs $0.072 per image. The price is known before the run starts. Usage is paid from prepaid credits; 1 credit equals $0.01.

Which settings does Flux 1.1 Pro Ultra support?

According to its input schema, Flux 1.1 Pro Ultra knows these parameters: prompt, raw, aspect_ratio (1:1, 16:9, 9:16, 3:2, 2:3, 21:9, or 9:21), and output_format (jpg or png).

How fast is Flux 1.1 Pro Ultra?

There are not enough measured runs of Flux 1.1 Pro Ultra on Railwail yet to state a run time. It depends on the input, the settings and the load at the provider.

Is Flux 1.1 Pro Ultra better than FLUX 1.1 Pro?

That depends on the task. Flux 1.1 Pro Ultra (Black Forest Labs) and FLUX 1.1 Pro (Black Forest Labs) are both models in the Image generation category. The comparison page shows their prices and specifications side by side.

Compare Flux 1.1 Pro Ultra and FLUX 1.1 Pro

How do I use Flux 1.1 Pro Ultra through the API?

Create a Railwail API key and send your request with the model ID flux-pro-ultra. Code examples for curl, Python and JavaScript are in the API section of this page.

Comparable models

All in this category

FLUX 1.1 ProBlack Forest Labs
Black Forest Labs' flagship text-to-image model. Faster generation than FLUX.1 Pro at higher prompt adherence, with strong photorealism and reliable spatial composition. Runs as a hosted Replicate model.
$0.048/image
33 % cheaper per unit
Compare Flux 1.1 Pro Ultra vs. FLUX 1.1 Pro
Flux DevBlack Forest Labs
Black Forest Labs' development model. Fast, high-quality image generation with LoRA support.
$0.0384/image
47 % cheaper per unit
Compare Flux 1.1 Pro Ultra vs. Flux Dev
Google Imagen 4Google DeepMind
Google DeepMind's Imagen 4 text-to-image model, hosted on Replicate. Sharp detail, accurate text rendering, and strong prompt adherence across photographic and illustrated styles. Outputs up to 2K resolution.
$0.048/image
33 % cheaper per unit
Compare Flux 1.1 Pro Ultra vs. Google Imagen 4

Use Flux 1.1 Pro Ultra via the API

One API key for every model on Railwail. Usage is charged from prepaid credits, 1 credit = $0.01.

Get API key Browse all models

Playground

Try Flux 1.1 Pro Ultra

Examples

Example prompts

Photorealistic Portrait

Architecture

Nature Macro

About Flux 1.1 Pro Ultra

Background

About Black Forest Labs

Architecture

Capabilities

Training & license

Research papers

Pricing

Cost calculator

Price calculator

API

Specifications

Input parameters

Tags

Use cases

What it is used for

Frequently asked questions

What is Flux 1.1 Pro Ultra?

How much does Flux 1.1 Pro Ultra cost on Railwail?

Which settings does Flux 1.1 Pro Ultra support?

How fast is Flux 1.1 Pro Ultra?

Is Flux 1.1 Pro Ultra better than FLUX 1.1 Pro?

How do I use Flux 1.1 Pro Ultra through the API?

Comparable models

Use Flux 1.1 Pro Ultra via the API