🔀 Z2J Seed Mixer

Somewhere in a complex workflow you end up with more seeds than you know what to do with: a KSampler seed, a lora seed, a wildcard seed, a noise seed - and you'd like them all to agree on one number so a change anywhere propagates deterministically. Z2J Seed Mixer is the smallest node in ComfyUI-Zero2JSON and arguably the most honest one: it takes up to four integers and hashes them into one deterministic seed.

That's it. No profiles, no prompt generation, no vocabulary. It's a utility node from the pack's utility family, and it earns its place by solving a real coordination problem.

How it works

The four seeds are packed and fed through the same xxhash32 that powers the whole pack, producing a single 32-bit integer. Because it's a pure hash, the same four inputs give the same output every time, on any machine - the same determinism guarantee the README promises for generation, applied to seed combination instead. Output stays in the valid seed range (0 to 4294967295), so you can wire mixed_seed straight into a KSampler or back into any Z2J generation node.

The inputs and outputs

• seed_1 - required, the primary seed.
• seed_2, seed_3, seed_4 - optional, default 0. Leave them out and it just hashes seed_1 plus zeros, which still works but is a waste of the node.
• Output: mixed_seed (INT).

Where it's genuinely useful: tying the whole workflow to one master seed. Put a single seed into this node alongside a per-node offset, and every dependent node - samplers and Zero2JSON generators alike - derives its own value from that one number. Change the master, everything downstream moves coherently. If you just need a stable seed for one thing, this is overkill; if you're fighting drift across a dozen nodes, it's the cure.

Install

Same repo as the rest of the pack:

cd ComfyUI/custom_nodes
git clone https://github.com/MushroomFleet/ComfyUI-Zero2JSON
cd ComfyUI-Zero2JSON
pip install -r requirements.txt

Restart ComfyUI. Only dependency: xxhash>=3.0.0. ComfyUI Manager: search "ComfyUI-Zero2JSON".

Where people get burned

The honest limit: it mixes numbers, not intent. Two different seeds that happen to hash to the same mixed value are indistinguishable to this node, and people occasionally expect it to preserve some notion of "these two seeds were related." It doesn't - it's a deterministic blender, and that's the whole job. Also note the outputs are invisible unless wired somewhere: a lone SeedMixer floating in your graph shows nothing on its own, which trips up exactly the beginners this pack tends to attract.