About Klein Studio
Klein Studio (flux3klein.org) is an independent, unofficial website run by Zehong Liu, an independent developer. This site is not affiliated with, endorsed by, or sponsored by Black Forest Labs. The FLUX and Black Forest Labs names are used here only for necessary attribution and descriptive reference.
How the site works
This web tool provides browser access to the FLUX 3 Klein (FLUX 3 Image Klein) model by sending requests to the API of Black Forest Labs, the company that makes the model. You can generate new images from text prompts or upload a single image to edit it with text instructions.
How it is paid for
Every visitor receives 3 free images per day at 1K resolution without creating an account. To cover API and server costs, we sell one-time image credit packs with no recurring subscription. Payments are processed through Waffo, which acts as our merchant of record. You can read the full details on our pricing page.
Safety and moderation
Every request passes up to four automated checks: (1) the prompt is checked against our own list of blocked terms, which we update over time without redeploying; (2) the prompt text is checked by Waffo Prompt Sift, the content-safety check of our payment provider Waffo; (3) when you edit a photo, the image you upload is checked by an image model (Llama 4 Scout on Cloudflare Workers AI) before it is sent to the model; (4) every finished image is checked the same way before it is shown. The model also has its own safety filter, built into Black Forest Labs’ API. If one of our checks cannot give an answer, the request is refused; if Prompt Sift asks for a manual review, nothing is made and you can try again later (usually within an hour).
A refused request uses no credit. If the prompt or the uploaded image is refused, no free image is used either; if our check holds back a finished image, a free image still counts as used, because the model ran. Every refusal is recorded in a moderation log with the stage, the kind of content, the rule that refused it and the time. Images are never stored in the log. How long the log is kept is listed in our privacy policy. Please also review our acceptable use policy.
Contact
If you have questions about the site, your credits, or a refund request, email support@flux3klein.org.