Generate Mashup Music · V4.5ALL

Mashup is the Suno endpoint nobody talks about and everybody eventually wants: hand it two songs, get one that sounds like both. This node is the V4.5ALL version of it, and it's a genuinely fun thing to have on a canvas next to your image and video work - it's how you get a soundtrack that matches the mood of a render instead of a stock loop.

What it actually does

Nothing local happens. The node builds the request, ships it to KIE.ai, and then blocks the queue polling the task until it's done or timeout_seconds (default 1200) runs out. The KIE transport model for the call is ai-music-api/mashup; the version V4_5ALL rides inside the input payload. Result comes back as a real ComfyUI AUDIO object.

The part that surprises people: the two source tracks are URLs, not audio sockets. upload_url_list is a JSON array widget - literally this, pasted in:

[
  "https://example.com/track-a.mp3",
  "https://example.com/track-b.mp3"
]

Each URL has to be publicly reachable by KIE's servers. Upstream uses only the first two entries, so adding a third is wasted effort. That's the whole reason this node is fussier than the generation nodes, which upload media for you.

Inputs worth your time

upload_url_list is required, as above. style and title are both required here - the mashup endpoint won't infer them - and prompt is required as a widget even though the endpoint treats it as optional narrative colour. It only becomes lyrics when lyrics is empty, and lyrics overrides it.

Then the dials: variety (integer 0–4) is the one actually worth understanding. 0 locks the output to one style, 1 is balanced, 2 gives you clearly different takes, 3 "bold exploration", and 4 is, in the author's own words, "unreasonably varied". Leave it at 1 unless you're deliberately hunting. style_weight, weirdness_constraint and audio_weight are the usual 0–1 nudges; vocal_gender is documented as a probability tweak, not a guarantee.

duration and persona_model are in the widget list but the docs scope them to the V5.5/V6 family, so on V4.5ALL they do nothing. Ignore them.

Outputs

audio is the decoded mashup - wire it to SaveAudio or into a video pipeline. all_urls_json keeps every URL the response returned (Suno usually returns more than one take, and audio is just the first), url is the primary one, task_id is the KIE job ID. raw_json is the full provider payload, which is the honest way to debug a weird result. credits_consumed and credits_left come back as floats and are also printed on the node after each run.

Install

ComfyUI Manager, search the pack title ComfyUI-KIE-Nodes-Next, or:

cd ComfyUI/custom_nodes
git clone https://github.com/felipederosilva/ComfyUI-KIE-Nodes-Next

Restart afterwards. The pack's only dependencies are requests, Pillow, numpy and PyYAML - no checkpoints to download, nothing to put in models/. Then set the API key once: Settings → KIE.ai Nodes Next → Connection → Paste / replace KIE.ai API key. It's validated against KIE before saving, lives in Comfy's user config rather than your workflow, and displays as a masked fingerprint. KIE_API_KEY in the environment overrides it for headless boxes.

Where it bites

Dead URLs are the number one failure. A local file path, a localhost link, or a Google Drive preview page will not work - KIE has to fetch the audio itself. If you generated tracks in this same graph, push them somewhere public first (the pack ships upload utility nodes under KIE Next / Utility for exactly this).

Version drift. KIE's docs list V4.5ALL as (Discontinued) alongside V4/V4.5/V4.5PLUS/V5/V5.5, with V6/V6_MINI/V6_WILD as the live family. This node exists because the page still documents it; a flat rejection usually means the version retired and it's time to switch to the V6 mashup node.

It's metered. Every run costs credits whether or not you like the output, and a mashup gives you a handful of takes and no refund. Cheap enough for a few experiments, not a fidget toy.

Not local, by design. Your source URLs and prompt go to a third-party service. That's inherent to every closed-model node - fine for a personal render, worth a second thought for a client's unreleased track.