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FLUX.1 Fill [pro]

FLUX.1 Fill [pro] is Black Forest Labs's dedicated inpainting model. It fills masked regions of images using text instructions while preserving the coherence, lighting, and style of the surrounding content.

Image Gen
index.ts
import { experimental_generateImage as generateImage } from 'ai';


const result = await generateImage({
  model: 'bfl/flux-pro-1.0-fill',
  prompt: 'A red balloon on a wooden table.'
});
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About FLUX.1 Fill [pro]

FLUX.1 Fill [pro] is a specialized model within Black Forest Labs's FLUX.1 lineup, available through AI Gateway since October 1, 2024 as part of the image-only model expansion. Unlike the Kontext models that focus on instruction-based editing, Fill Pro is specifically engineered for inpainting: generating content for a defined masked area within an existing image.

Inpainting requires a model that simultaneously understands the unmasked context (colors, textures, lighting direction, perspective, stylistic character) and generates new content for the masked region that blends seamlessly. FLUX.1 Fill [pro] treats this as its primary function, making it more appropriate for mask-based fill workflows than general-purpose editing models.

Practical applications include object removal and replacement, background extension (outpainting), e-commerce product photo cleanup, and generative content insertion (placing a new element by masking its target region and describing it in a text prompt).