EvoLink Kling O3 Text-to-Video (Official)

EvoLink_KlingO3T2V is the plain text-to-video member of Kling's newest generation, and it's the least fussy node in the O3 family: prompt in, up to 4K clip out, no reference images required. Kling's O3 line is the current flagship from Kuaishou, and this node carries the full feature set - up to 4K, generated sound, any duration from 3 to 15 seconds. If you want a hero-quality clip straight from a description, this is the Kling node that does it without any extra inputs to manage.

The inputs that matter

• prompt (required) - shot and motion description, up to 2500 characters, Chinese-friendly. The tooltip points at multi-shot setups in the API docs if you want to go advanced.
• duration - 3–15 seconds, default 5, billed by duration.
• quality - 720p (default), 1080p, or 4k.
• aspect_ratio - 16:9 (default), 9:16, or 1:1. Vertical shorts → 9:16.
• sound - off (default) or on. Generated sound effects; this is where the O3 tier beats Kling Turbo, which doesn't support sound at all.

Then the pack-standard api_key and timeout_seconds (1200).

How it works

The job posts to POST /v1/videos/generations as kling-o3-text-to-video, and the pack polls the task until the clip completes, showing a progress bar on the node. The finished video downloads to your machine as a VIDEO object - wire video into a native Save Video node to keep it. The other outputs are task_id (dashboard logs), status_info (model/runtime/credits), result_urls (24h expiry), and response_json. Failed or blocked jobs don't charge, and rerunning unchanged params reuses ComfyUI's cache.

Because the output is a VIDEO type, you need a recent ComfyUI with comfy_api support - old installs error with a message about missing VIDEO output.

Installing

No GPU, no model files, only requests:

cd ComfyUI/custom_nodes
git clone https://github.com/deeplearning-goethe/comfyui-evolink.git

then fully restart ComfyUI, or install via ComfyUI Manager by searching EvoLink.

Troubleshooting

Pack-standard errors (401 key, 402 balance, 403 access, 429 rate limit) and the VPN note - whitelist api.evolink.ai and files-api.evolink.ai. Budget-wise, remember 4K costs a lot more than 720p per run; use the cheap tier for drafts and keep 4K for the keepers. And if you enable sound, expect the run to take longer - audio generation rides along with the video pass, and the timeout default of 1200s exists for a reason.