Is None

Nifty Is None answers the single most useful question in ComfyUI logic: "is this input actually connected and holding a value?" It takes anything in and hands you a BOOL saying whether it's None - which in ComfyUI terms means "not connected, or explicitly set to None."

That one boolean is the root of every conditional graph. Optional inputs are everywhere: an image from a failed detection, an optional mask slot, a LoRA that a workflow variant doesn't load. Before you can route around a missing value, you have to know it's missing - and this node is the clean way to ask.

The inputs that matter

• input - any type, fully optional. Leave it unconnected and the node answers "yes, it's None."
• negate - flip the result. On, it returns True when the input isn't None (a "Has Value" test).

Output: BOOLEAN - True if input is None, before negation.

How to actually use it

The standard pattern pairs it with one of Nifty Nodes' switches. Is None → Nifty Input Switch: if the value is None, route to a fallback; otherwise pass the real value through. That's the skeleton of half the conditional workflows people post about, and Nifty's logic suite is built so the two snap together - Is None's BOOL feeds boolean directly, and the lazy Input Switch then only evaluates the branch you actually need.

The negate toggle is easy to overlook and genuinely handy: it lets you read the node as "Has Value" without adding an inverter, which keeps small graphs tidy. And since the input accepts any type, the same node guards images, latents, strings, and even custom BUNDLE values.

One thing worth knowing: "not connected" and "connected but empty" are treated the same way here. If you need to distinguish an explicit empty string from a missing connection, this isn't the tool - but for almost every routing decision, None-or-not is exactly the right question.

Install

Same pack as everything else here: ComfyUI Manager → search "Nifty Nodes", or

cd ComfyUI/custom_nodes
git clone https://github.com/Stibo/comfyui-nifty-nodes

Restart ComfyUI. Nifty Nodes is a recent v3-API pack (v2.1.0, mid-2026), so keep ComfyUI updated. The node is dead simple, but it's the predicate that powers the entire logic suite - install the pack for the switches, and this is the node that makes them answer the right question.