FLUX 3 Image

FLUX 3 Image is an image generation and editing model developed by Black Forest Labs (BFL). It generates images from written descriptions, combines up to ten reference images, and accepts bounding boxes to guide the placement or editing of individual elements.^[1] BFL's release notes date the product's release to October 1, 2026.^[2]

Background

BFL introduced the FLUX 3 family on July 23, 2026. The company described a shared architecture trained jointly on images, video, and audio, based on its Self-Flow research. Its rollout separated image synthesis and editing from FLUX 3 Video, action prediction, and a planned open-weight backbone called FLUX 3 Dev. The July announcement described image evaluations as preliminary and said image early access would follow in subsequent weeks. That announcement therefore documents the family and its planned rollout, rather than the October image release.^[3]

Generation and editing

A text prompt can describe a new scene without reference images or boxes. For editing, the request supplies an image and an instruction identifying the requested change. Multiple references can contribute different parts of a composition, such as a setting from one image and an object from another. BFL's overview also documents web and image search grounding, enabled by default; disabling it makes generation rely on the supplied prompt instead of external searches.^[1]

The product page describes native 2K and 4K generation and illustrates 4K output with an image measuring 5456 x 3072 pixels. Its agent workflow uses a language model to turn a short scene description and aspect ratio into a caption and an element table. The user can adjust that proposed layout before generation.^[4]

An edit does not always require a manually drawn box. The editing documentation says FLUX 3 Image expands instructions into a detailed prompt and, for many edits, identifies the named element and supplies a box automatically. The returned result.prompt exposes that expanded instruction. References can be identified by their position in the input list or by their content.^[6]

Bounding-box control

The layout prompt contains a scene caption followed by a JSON array. Each generated element has an id, a bbox, and a desc; the caption refers to the identifier in angle brackets. Coordinates are integers on a normalized 0-1000 grid, ordered [top, left, bottom, right], equivalent to [y_min, x_min, y_max, x_max]. The boxes are part of prompt, not a separate API parameter.^[5]

Editing rows use from, src_bbox, and tgt_bbox to connect source elements to their intended output positions. ref_image_0 identifies the first reference image.^[5]

Boxes guide placement and scale; the documentation explicitly says they are not clipping masks, and elements can extend beyond them.^[5]

API inputs and output

The service accepts POST https://api.bfl.ai/v1/flux-3-image, authenticated with an API key in the x-key header. Its request schema includes the following fields.^[7]

Resolution classes specify equal pixel areas; actual dimensions depend on the aspect ratio. With auto, a ratio requested in the prompt takes precedence, followed by the first reference's framing, with square output as the fallback.^[7]

Each reference must be at least 256 x 256 pixels and no larger than 16 megapixels.^[1] Generation and editing share the same endpoint without a mode field. The text-to-image guide warns that unsupported fields, including seed, width, and input_image, produce HTTP 422 validation errors.^[8]

Requests run asynchronously. Submission returns a task identifier and polling_url, which the client must use because it points to the region holding the task. The client polls until completion and downloads result.sample when the status becomes Ready; the image URL must be used within one hour. A completed result also reports the expanded prompt and generation duration.^[8]

The guide distinguishes blocked inputs from blocked outputs through Request Moderated and Content Moderated statuses. It also cautions that a failed task can return HTTP 503 with a normal JSON response: the status in that response determines what happened.^[8]

Access and pricing

BFL provides browser access through its playground and a Precise Editing tool.^[1][10] The latter accepts an uploaded image through file selection, drag-and-drop, or clipboard paste, and offers sample images for editing.^[10] BFL also advertises a commercial weights license allowing companies to fine-tune and deploy the image model on their own infrastructure.^[4]

The pricing documentation lists the following per-image charges, checked on October 2, 2026. API and playground prices are the same, with one credit worth US$0.01.^[9]

The pricing table does not list a separate 1.5k rate. The submission response includes the cost of the individual request.^[9]

Editing limits

BFL's editing guide qualifies its pixel-preservation claims: pixels outside edited boxes usually remain identical, but shadows, reflections, or nearby lighting can change. It also reports that newly requested elements sometimes fail to appear in very small boxes, citing boxes around 40 x 25 pixels in its tests. These are vendor-documented observations, not an independent guarantee of unchanged pixels. The guide advises giving text its own box and stating additions or removals in the written instruction as well as the element rows.^[6]

References

1. ^1 ^2 ^3 ^4Black Forest Labs. FLUX 3 Image. Documentation, accessed October 2, 2026.
2. ^Black Forest Labs. Release Notes. FLUX 3 Image entry, October 1, 2026.
3. ^Black Forest Labs. FLUX 3: Real World Models. July 23, 2026.
4. ^1 ^2Black Forest Labs. FLUX 3 Image. Product page, accessed October 2, 2026.
5. ^1 ^2 ^3 ^4 ^5 ^6 ^7Black Forest Labs. Bounding boxes with FLUX 3 Image. Documentation, accessed October 2, 2026.
6. ^1 ^2Black Forest Labs. FLUX 3 Image Editing. Documentation, accessed October 2, 2026.
7. ^1 ^2 ^3 ^4 ^5 ^6 ^7 ^8 ^9Black Forest Labs. Generate an image with FLUX 3. API reference, accessed October 2, 2026.
8. ^1 ^2 ^3Black Forest Labs. FLUX 3 Text to Image. Documentation, accessed October 2, 2026.
9. ^1 ^2 ^3 ^4 ^5 ^6Black Forest Labs. API pricing. FLUX 3 Image rates, accessed October 2, 2026.
10. ^1 ^2Black Forest Labs. Precise Editing. Browser tool, accessed October 2, 2026.