FLUX.1 Fill [dev]

FLUX.1 Fill [dev] is the inpainting specialist of the FLUX family, and this node wraps it the clever way: through ACE++, a task framework that turns "what do you want done?" into modes. Instead of one inpainting pipeline, you get three - portrait, subject, and local editing - plus a repainting-scale dial that trades identity preservation against prompt adherence. It's the most flexible editing node in the Runware pack, and also the easiest to confuse yourself with.

The model runs on Runware's hardware (runware:102@1), so you get FLUX-quality fills with zero local footprint.

How it works

A taskType: imageInference REST call. The input image(s) ride up as data URIs, and the ACE++ mode (acePlusPlus.type) tells the model what kind of task this is. The classic local ComfyUI "load image + mask + prompt" inpaint path is here too (seedImage, maskImage), so you're not forced into the ACE++ way - you just get both.

Inputs that matter

• acePlusPlus.images - required; the reference image(s). This is the ACE++ socket, distinct from seedImage.
• acePlusPlus.type - portrait / subject / local_editing. Portrait keeps a face recognizable, subject targets an object, local_editing is free-form region work. Pick per job.
• acePlusPlus.repaintingScale - 0–1. The whole interesting dial: 0 preserves original character/identity, 1 surrenders to the prompt. Start around the middle and nudge toward 0 when the edit keeps drifting off the subject.
• acePlusPlus.masks - optional masks for the ACE++ path.
• seedImage / maskImage / outpaint - the classic inpaint/outpaint route, if you prefer it.
• lora / controlNet / ipAdapters / pulid - the full builder socket suite. pulid is notable: face-ID preservation on top of portrait editing.
• layerDiffuse - toggle for transparent-image generation.
• steps / scheduler / CFGScale / strength / maskMargin - the standard diffusion dials, all off-by-default toggles with paired value widgets.

Install

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

Or ComfyUI Manager → search Runware → Install → restart. API key in ComfyUI Settings → Runware API key or RUNWARE_API_KEY.

Gotchas

• Two input paths (ACE++ vs classic mask) means two ways to get nothing. Pick one: if you're feeding acePlusPlus.images, configure the ACE++ settings; if you're doing classic inpaint, wire seedImage + maskImage and let acePlusPlus.type sit at its default.
• The off-by-default toggles are a deliberate design: values with usage rules start hidden so a default request never violates them. If a setting seems missing, flip its enable toggle first.
• advanced_json is the escape hatch (documented for hiresFix), and invalid JSON is silently ignored - so check your syntax if a tweak doesn't land.

Fill [dev] is the "one editor for everything" node - portraits, objects, local fixes, even transparent output. The ACE++ modes and repainting scale make it genuinely more capable than a plain inpaint wrapper. Just don't fight it by mixing both input paths.