FLUX is Black Forest Labs' family of text-to-image and image-editing models, sold through a pay-per-use API rather than a subscription. It spans both open-weight releases such as FLUX.1 [dev] and FLUX.2 [dev], and commercial API-only models including FLUX.1 Kontext and FLUX.2 [pro].
Who builds it
FLUX is developed by Black Forest Labs, a company operating at bfl.ai that positions itself as a research-driven image-model lab rather than a consumer app. Instead of one single product, Black Forest Labs ships a line-up of models under the FLUX name, ranging from weights researchers and developers can download and run themselves to hosted, commercial-grade models accessed purely through the API. This dual structure — open-weight research releases alongside closed, paid production models — is the core of how Black Forest Labs positions itself against both open-source competitors and fully closed API vendors.
What it does
FLUX handles both generation from a text prompt and editing of existing images, with support for inpainting-style edits and legible text rendered inside an image. According to Black Forest Labs' own documentation and its FLUX.2 announcement, generation and editing are supported at resolutions up to 2048x2048 pixels, or roughly 4 megapixels. Because the model line spans open-weight and API-only variants, the practical capability available to a given user depends on which FLUX model they choose — a locally run FLUX.1 [dev] checkpoint versus the hosted FLUX.2 [pro] model accessed over the API.
Pricing
FLUX is a paid product: Black Forest Labs' pricing page prices API usage on a pay-per-use basis rather than offering a free-forever tier, and the API documentation confirms an EU hosting option for users with data-residency requirements. There is no published free tier for the hosted API in Black Forest Labs' own materials — access to the open-weight models by downloading and self-hosting them is the closest option to using FLUX without paying Black Forest Labs directly, though that path carries its own licensing conditions.
Rights and provenance
Rights depend on which FLUX model is in use. Black Forest Labs' Terms of Service and its FLUX.1 [dev] non-commercial license terms together define a commercial-use picture with limits, not a blanket allowance: output from the hosted, commercial API models is usable under the Terms of Service, while the downloadable open-weight [dev] models are licensed for non-commercial use unless a separate commercial license is obtained from Black Forest Labs. In both cases, ownership of generated output sits with the user rather than with Black Forest Labs, per the same Terms of Service and license documents. On the provenance side, Black Forest Labs' Hugging Face model card for FLUX.2-klein-9B documents C2PA-based content credentials, the same open industry standard for labeling AI-generated media that other major image models use.