Kling Pro v1.0 Video Generation (fal)

Kling ships in tiers, and this is the older, cheaper Pro v1.0 endpoint. If Master is the hero-shot tier, Pro is the one you use to explore - it's less expensive per clip, which makes it the sensible place to iterate on prompts and framing before you spend real money on a premium render. This node runs it from ComfyUI, and it flexes three ways: text-to-video, image-to-video, and start-plus-end-frame.

What it actually does

Nothing runs on your machine. Prompt and optional images go to fal.ai, fal runs Kling Pro, and a clip comes back - no VRAM, no downloads, billed per generation. It's the same Kling motion quality lineage at a lower tier: not the absolute best the family offers, but solid, and cheap enough to actually experiment with.

The inputs that matter

• prompt (required): the scene and the action, in plain cinematic language.
• duration: 5 or 10 seconds. Ten roughly doubles the cost.
• aspect_ratio: 16:9, 9:16, or 1:1.
• image (optional): supply one to animate a still (image-to-video); leave it empty for text-to-video.
• tail_image (optional): a target end frame. Give it both image and tail_image and Kling generates a transition from one to the other.

That's the whole surface - no sampler, steps, or CFG, because all of that lives on fal's side. The output is a single STRING, the video URL; download it with the pack's Fal Save Media from URL node.

Installing it

Easiest: ComfyUI Manager → search ComfyUI-fal-API → install → restart. Manual:

cd ComfyUI/custom_nodes
git clone https://github.com/gokayfem/ComfyUI-fal-API.git
cd ComfyUI-fal-API
pip install -r requirements.txt

Restart ComfyUI. No model file; the dependencies are fal-client and a fal API key (in config.ini under [API], or the FAL_KEY env var). No key, no video.

Where people get burned

The honest note on this one is the version number: v1.0 is an older Kling generation. It's a great place to iterate cheaply, but if the motion quality feels a step behind what you've seen from Kling lately, that's expected - move your final render to a newer tier (v2.1 Pro or Master) once you've locked the prompt. Treat Pro v1.0 as your sketchpad, not your finish line.

Everything else is standard: the start-plus-end mode wants two compatible frames or the transition gets awkward, content-policy refusals on people surface as readable fal errors, and the Windows Portable import fix is .\python_embeded\python.exe -m pip install fal-client.