FLUX by Black Forest Labs

FLUX is a family of open and pro text-to-image models from Black Forest Labs, prized for photorealism and prompt accuracy.

Overview

FLUX burst onto the scene as an open-weights model family from the team behind Stable Diffusion, and it quickly became a benchmark leader for image quality and prompt adherence. The family spans fast, freely downloadable versions for local use and commercial-grade pro models served via API. Because weights are available, FLUX powers countless third-party apps, fine-tunes, and ComfyUI workflows. The models handle hands, text, and complex compositions notably well.

Key Features

• Open-weight variants (schnell and dev) for local and research use
• Pro models with top-tier photorealism and typography via API
• Strong prompt adherence, including counting, spatial relations, and legible text
• Broad ecosystem support: ComfyUI, Automatic1111, and hosted apps
• Fine-tuning friendly with LoRA support for custom styles
• Fast generation speeds optimized for both consumer GPUs and servers

Pricing

Open-weight FLUX models are free under their licenses (non-commercial for some variants). Hosted API access to pro models is metered per image, and many third-party apps include FLUX in their own subscription plans.

Who Is It For

Developers, researchers, and creators who want local, customizable image generation or best-in-class quality through an API.

Popular Use Cases

Developers self-host FLUX for private, unlimited generation on consumer GPUs. Research labs fine-tune it for specialized domains like medical or satellite imagery. Creative agencies use API access for high-volume campaign imagery with strong prompt fidelity.

Tips for Best Results

Use schnell for fast drafts and dev or pro models for finals. Fine-tune with LoRAs when you need a repeatable brand or character look across thousands of images.

Workflow & Integration

Self-hosters wire FLUX into ComfyUI graphs with upscalers and ControlNet-style conditioning for production pipelines. Businesses call the hosted API for burst workloads while keeping local models for prototyping, and fine-tuned LoRAs are shared internally as reusable brand assets.

FAQ

Is FLUX free to use?

Yes for open-weight variants within their license terms; pro API models and commercial deployments are paid.

Does FLUX offer an API?

Yes, Black Forest Labs and many partners provide metered APIs for FLUX pro models.

How does FLUX compare to alternatives?

FLUX rivals top proprietary models on realism and control, with the added advantage of downloadable weights.

Can I fine-tune FLUX?

Yes, the open variants support LoRA fine-tuning with widely available community tooling.

What hardware do I need to run FLUX locally?

A modern GPU with 12GB+ VRAM is comfortable; optimizations exist for lower-memory cards.

Is FLUX really open source?

Weights are open under license terms that differ per variant — schnell is permissive, dev is non-commercial unless licensed.

Which tools run FLUX locally?

ComfyUI, Automatic1111 forks, and Diffusers all support FLUX models.