RFC: Variable length node inputs

[huchenlei]

Summary

This RFC proposes adding support for variable-length inputs in ComfyUI nodes, allowing a single node to accept a dynamic number of inputs. The feature introduces a new var_length input type configuration that enables nodes to handle multiple inputs through either socket connections or widget inputs, with configurable minimum and maximum input counts. This eliminates the need for multiple fixed-input node variants or chained node connections, resulting in cleaner workflows and more maintainable code.

Links

• Full Rendered Proposal

• Discussion Thread

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[huchenlei]

Note: 2025-04-29

Implementation scoping:

Backend change

Detect the connection groups, e.g. cond_1, cond_2, ..., and compress them into a single list/tuple before binding to node func args.

Frontend change

When configuring node, the var length inputs need to be properly detected and mapped. Ref: https://github.com/Comfy-Org/ComfyUI_frontend/blob/df723b56dab789bd0e9302c8793e73a4b658a1c0/src/services/litegraphService.ts#L231

Multiple var length arg should be supported.