Typed parameters

Added in version 25.10

A script can declare parameters using the params block:

params {
    // Path to input data.
    input: Path

    // Whether to save intermediate files.
    save_intermeds: Boolean
}

workflow {
    analyze(params.input, params.save_intermeds)
}

Features

Parameters can use all standard types except the dataflow types (Channel and Value).

Typed parameters should only be referenced in the entry workflow or output block. Parameters can be passed to workflows and processes as explicit inputs.

The command line, params file, or config file can override the default value. Parameters from multiple sources are resolved in the order described in Pipeline parameters. Nextflow converts command-line parameters to the type set by their annotation.

A parameter that doesn't specify a default value is a required parameter. If a required parameter has no value at runtime, the run fails.

For more information about standard types, see Types.

Added in version 26.04

Boolean parameters that don't specify a default value default to false.