Flux 3 Klein API
black-forest-labs/flux-3-kleinImageMake images with Flux 3 Klein through UberLLM: $0.008 per image. Requests are served by third-party providers. Made by flux. No UberLLM fee on requests. Adding credit by card costs 5.5% + $0.50.
Here, sellers serve it through their own provider accounts. Where the capacity comes from
How much does Flux 3 Klein cost per image?
On October 31, 2026, Flux 3 Klein costs $0.008 per image through UberLLM. Prices come from sellers on the UberLLM market and change during the day. A picture that fails costs nothing, and UberLLM adds no fee.
Flux 3 Klein pricing
Prices as of 18:00 UTC.
Each request is sent to an available third-party provider for this model and retried if the provider fails before it starts answering. No UberLLM fee on requests. Adding credit by card costs 5.5% + $0.50.
How to use it
One request with your UberLLM key; the image comes back in the answer.
# Make an image: the answer comes back when it is ready.
curl https://api.uberllm.dev/v1/images/generations \
-H "Authorization: Bearer $UBERLLM_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model": "black-forest-labs/flux-3-klein", "prompt": "a red apple on a white table", "n": 1, "size": "1024x1024"}'
# → {"created": …, "data": [{"url": "https://api.uberllm.dev/v1/media/artifacts/<id>/0"}]}
# (or "b64_json" when you send "response_format": "b64_json")
# Download it
curl -L -o image.png -H "Authorization: Bearer $UBERLLM_API_KEY" "https://api.uberllm.dev/v1/media/artifacts/<id>/0"The clip lengths, sizes and other choices this model takes: GET https://api.uberllm.dev/v1/models/black-forest-labs/flux-3-klein. Add "validate": true to see the most a request can cost without paying. Guide
Flux 3 Klein API FAQ
How do I make an image with Flux 3 Klein?
Send a POST to https://api.uberllm.dev/v1/images/generations with your UberLLM key, model "black-forest-labs/flux-3-klein" and a prompt. The image comes back in the answer.
Compared with other providers: One API for text, image and video