PVL Kontext Pro (fal.ai)

Flux Kontext came in two tiers: Pro and Max shipped as API-only in May 2025, and the Dev weights went open a month later. If you want the top tier - the one that never ran locally, the best of the Kontext line - an API is the only way to touch it. This node is that: it wraps fal.ai's fal-ai/flux-pro/kontext endpoint so you can drive the Pro model from a ComfyUI graph. It's the same "feed an image and a sentence" instruction editing Kontext made famous - watermark removal, clothing swaps, background replacement - just on the bigger, non-open sibling.

If you already have the open Dev weights and a GPU that fits 12B, you probably don't need this. But if you're on a weak machine, renting cloud time anyway, or just want the Pro-tier result without babysitting weights, this is the cleanest path. It's part of the pvlprk/comfyui-pvl-api-nodes pack, so it shares the install and the "every run costs fal credits" reality with its siblings.

How it works

The node base64-encodes your image and POSTs it with the prompt and settings to https://fal.run/fal-ai/flux-pro/kontext. Then it does something worth knowing about: it actively checks the response for trouble. If the API flags has_nsfw_concepts, it raises an error. If the returned image comes back all-black (a common "filtered/failed" signal), it raises an error instead of silently handing you a black frame. That's more defensive than most nodes in this pack, and it saves you from debugging mysterious black outputs.

Inputs that matter

• prompt and image are required - that's the whole editing interface.
• aspect_ratio gives you the full preset ladder (21:9, 16:9, 4:3, 3:2, 1:1, 2:3, 3:4, 9:16, 9:21; default 1:1) - a Kontext Pro nicety you don't always get on the Dev nodes.
• safety_tolerance (1-6, default 2) is passed through to the endpoint; higher tolerances allow more permissive content, but the node will still refuse if the API reports NSFW concepts.
• CFG (3.5), num_images (1-4), seed (-1 random), output_format (jpeg default / png), sync_mode.

One IMAGE output.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/pvlprk/comfyui-pvl-api-nodes

Restart and set FAL_KEY in the environment that launches ComfyUI (fal.ai/dashboard). Standard for the pack.

Where people get burned

• Pro is a paid, hosted model - treat every run as money. There's no local fallback and no free tier behavior; a single edit is a single API charge.
• It's fully cloud-bound. No Dev weights, no offline mode, no "run it on my 3090" escape hatch. If fal is down, so is your edit.
• The NSFW guardrail is real and enforced. safety_tolerance up doesn't bypass has_nsfw_concepts - the node hard-fails when the API flags content. If that's your workflow's need, the KB's pointer to Qwen-Image-Edit (Apache 2.0, uncensored) is the usual recommendation.
• Don't expect a mask. This is the pure instruction editor; for masked, region-limited edits reach for PVL Kontext Dev Inpaint in the same pack.