Black Forest Labs allows fine-tuning of the Flux AI image generator

Black Forest Labs has quickly made a name for itself as the premier, high-quality, open source AI imaging startup—even surpassing quality of the models offered by Stability AI, where the founders of Black Forest Labs previously worked. It also briefly served as the default image generator in xAI’s Grok language model.

Today, Black Forest Labs takes this a step further, announcing the release on FLUX Pro Finetuning APIa tool that enables creators to customize generative AI models using their own images and concepts.

Designed for professionals in marketing, branding, storytelling and other creative industries, the API enables the customization of the company’s flagship FLUX Pro and FLUX Ultra models with a user-friendly approach.

Customization at scale

The FLUX Pro Finetuning API allows users to fine-tune generative text-to-image models with five to 20 training images, optionally accompanied by text descriptions.

This process results in custom models that maintain the generative flexibility of the FLUX Pro base models while aligning the results with specific creative visions. The tool supports multiple modes, including ‘character’, ‘product’, ‘style’ and ‘general’, making it adaptable to a wide variety of use cases.

Trained models can seamlessly integrate with endpoints such as FLUX.1 Fill, Depth, Canny, and Redux, as well as high-resolution generation capabilities up to four megapixels. Whether to create brand-aligned marketing visuals or detailed character art, the API improves precision and adaptability in AI-generated content.

Practical applications and use cases for brands, marketers and more

Using the FLUX Pro Finetuning API, professionals can create custom models that preserve essential design elements, character consistency, or brand properties. A survey conducted by Black Forest Labs showed that 68.9% of users prefer FLUX Pro’s fine-tuned results over competing services.

Some highlighted applications include:

• Inpainting: Using FLUX.1 Fill for iterative edits to refine images

• Structural control: Integration with FLUX.1 Depth to improve image generation with precise structural corrections

• Visual branding: Ensuring consistency in marketing materials and campaigns

Partnership with BurdaVerlag

Black Forest Labs has partnered with BurdaVerlaga leading German media and entertainment company to demonstrate the potential of the FLUX Pro Finetuning API. BurdaVerlag’s creative teams use the tool to develop custom FLUX models tailored to their brands, such as the children’s edition Lisi PONY.

With this integration, BurdaVerlag’s design teams can create visuals that reflect each brand’s identity while exploring new creative directions. The application programming interface (API) accelerated their production workflows, enabling the generation of high-quality content at scale.

Affordable prices and availability

The FLUX Pro Finetuning API is now available via API endpoints via the Flux.1 (dev) model. Prices for all FLUX models in the Black Forest Labs API are as follows:

• FLUX 1.1 (Professional) Ultra: $0.06 per image

• FLUX 1.1 (Professional): $0.04 per image

• FLUX.1 (professional): $0.05 per image

• FLUX.1 (dev): $0.025 per image

Getting started is easy

The fine-tuning process requires minimal user involvement. Upload training images in supported formats (JPG, JPEG, PNG or WebP) with resolution limited to one megapixel for optimal results. Advanced configuration options allow fine-grained control over the learning process, including number of iterations, learning rates, and trigger words for precise, fast integration.

Black Forest Labs also provided extensive resources including a Beta Guide for fine-tuning and Python scripts for easy implementation. Users can monitor progress, adjust parameters, and test results directly through API endpoints, ensuring a smooth and efficient workflow.

By combining flexibility, ease of use, and professional-grade results, the FLUX Pro Finetuning API sets a new standard for custom content creation in generative AI. With the tool now available, Black Forest Labs aims to transform the way individuals and organizations approach custom media generation, unlocking creative possibilities on an unprecedented scale.