If node

The If node splits a flow in two. It evaluates a condition and sends the flow down either the true port or the false port — the basic building block for "do this, otherwise do that".

Component id: flowrunner/if.

Two ways to write the condition

If supports two condition formats. If a structured expression is present it wins; otherwise the engine falls back to a text condition.

Structured expression (expression)

A structured expression is the format the visual condition builder produces. It's a tree of comparisons combined with and / or groups. Each comparison has a left operand, an operator, and (for most operators) a right operand. Operands are either a reference (variable.field) or a literal.

Supported operators:

Operator	Meaning	Right side
== / !=	equal / not equal	required
> < >= <=	numeric comparison	required
contains	left string contains right string	required
startsWith / endsWith	string prefix / suffix	required
truthy	left value is truthy	none
falsy	left value is falsy	none

Groups combine children: an and group is true when every child is true; an or group is true when any child is true. An empty group evaluates to true.

Text condition (condition)

When no structured expression is set, the engine reads the condition string and runs a small, deliberately-limited evaluator. It supports a single comparison — no &&, ||, parentheses, or function calls:

start.age >= 18
response.status == 200
start.role != "admin"
result.count            # bare ref → truthy check

Both sides may be references or literals. Literals are numbers, "quoted strings", true, false, or null. A dotted token like start.age reads from refs; a bare token is treated as a namespace lookup.

Config

Field	Required	Description
expression	No	Structured condition tree (kind: 'group' | 'cmp'). Used when present.
condition	No	Text condition string. Used as the fallback when there is no structured expression.

Ports

Port	Followed when
true	The condition evaluated to true.
false	The condition evaluated to false.

If evaluating the condition throws an error, the flow goes down false — unless you have wired an error port, in which case the failure routes there instead.

Example

Route paying customers differently from free users:

If  condition: start.plan == "pro"
  true  → grant premium access
  false → show upgrade prompt

TIP

For anything more complex than one comparison — multiple conditions combined with and/or — use the structured expression builder rather than the text condition, which only handles a single comparison.

See also

• Switch node
• ForEach node
• Working with flow data
• Node reference overview