Expression

Type key: expression_node
Group: Data
Category: data
Tier: CORE

The Expression node evaluates dynamic expressions to compute new fields, perform calculations, transform strings, and apply conditional logic. It is more powerful than simple {{tag}} replacement and is the go-to tool for computed fields without writing PHP.

Handles

Handle	Direction	Description
`input`	Input	Receives data from the preceding node
`output`	Output	Emits input data with computed fields added/replaced

Configuration

Field	Type	Default	Description
`expressions`	array	`[]`	Array of expression definitions
`pass_through_input`	boolean	`true`	Include all original input fields in the output
`evaluation_mode`	enum	`per_record`	`per_record` or `dataset`

Expression Object

{
    "field": "price_with_tax",
    "expression": "{{input.price}} * 1.22"
}

Property	Description
`field`	Output field name where the result is stored
`expression`	The expression to evaluate

Expression Syntax

Arithmetic

{{input.subtotal}} + {{input.shipping}}
{{input.quantity}} * {{input.unit_price}}
{{input.total}} / {{input.count}}
{{input.value}} % 100

Comparison (returns boolean)

{{input.score}} > 80
{{input.age}} >= 18
{{input.status}} == "active"

Ternary Operator

{{input.quantity}} >= 10 ? 0.15 : 0.05
{{input.vip}} == true ? "VIP" : "Standard"

String Concatenation

{{input.first_name}} + " " + {{input.last_name}}

Built-in Functions

String Functions

Function	Description	Example
`$upper(str)`	Convert to uppercase	`$upper({{input.name}})`
`$lower(str)`	Convert to lowercase	`$lower({{input.email}})`
`$trim(str)`	Remove whitespace	`$trim({{input.code}})`
`$length(str)`	String length	`$length({{input.description}})`
`$replace(str, search, replace)`	Replace substring	`$replace({{input.text}}, "foo", "bar")`
`$contains(str, needle)`	Check substring	`$contains({{input.tags}}, "urgent")`
`$substr(str, start, length)`	Extract substring	`$substr({{input.code}}, 0, 3)`

Math Functions

Function	Description	Example
`$round(num, decimals)`	Round to N decimal places	`$round({{input.price}}, 2)`
`$floor(num)`	Round down	`$floor({{input.score}})`
`$ceil(num)`	Round up	`$ceil({{input.average}})`
`$abs(num)`	Absolute value	`$abs({{input.delta}})`
`$min(a, b)`	Minimum	`$min({{input.a}}, {{input.b}})`
`$max(a, b)`	Maximum	`$max({{input.a}}, {{input.b}})`

Date Functions

Function	Description	Example
`$dateFormat(date, format)`	Format a date	`$dateFormat({{input.created_at}}, "d/m/Y")`
`$dateDiff(date1, date2, unit)`	Difference between dates	`$dateDiff({{input.start}}, {{now}}, "days")`
`$dateAdd(date, amount, unit)`	Add time to a date	`$dateAdd({{input.date}}, 7, "days")`
`$now()`	Current datetime string	`$now()`

Currency Functions

Function	Description	Example
`$currency(value, code, locale, decimals)`	Format a number as currency string	`$currency({{input.total}}, "EUR", "it_IT", 2)`
`$currency_it(value, decimals)`	Shortcut for EUR + italian locale	`$currency_it({{input.total}}, 2)`

Function signature:

$currency(value, currencyCode = 'EUR', locale = 'it_IT', decimals = 2)

value: numeric value to format
currencyCode: ISO-like code (e.g. EUR, USD, GBP, CHF, JPY)
locale: formatting style hint (e.g. it_IT, en_US, de_DE)
decimals: number of decimal digits

Important: locale must be a quoted string literal:

$currency({{input.total}}, "USD", "en_US", 2)   // ✅
$currency({{input.total}}, "USD", en_US, 2)     // ❌

Examples by locale:

$currency({{input.total}}, "EUR", "it_IT", 2)   // 4.048,00 €
$currency({{input.total}}, "USD", "en_US", 2)   // $ 4,048.00

Important: currency helpers do not divide by 100 automatically. If your values are in cents, divide explicitly:

$currency({{input.total}} / 100, "EUR", "it_IT", 2)

Evaluation Modes

`per_record`

Expressions are evaluated once per item in the dataset. Use this when the input is a single record or when processing inside a For Each loop.

`dataset`

Expressions are evaluated once against the entire dataset object. Use this for meta-level computations that operate on the whole context (e.g. counting records, computing totals across the dataset).

Examples

Calculate Total with VAT

Expression node — VAT calculation example

{
    "field": "total_with_vat",
    "expression": "{{input.subtotal}} * 1.22"
}

::: info 💾 Try this example Download the workflow JSON — open an empty workflow and import the file. :::

Expression inside For Each (greeting per user)

With For Each, each iteration exposes the current item as input. An Expression node in per_record mode can build fields such as a personalized greeting from {{input.name}}.

Expression node inside ForEach — greeting per user

::: info 💾 Try this example Download the workflow JSON — open an empty workflow and import the file. :::

Conditional Discount

{
    "field": "discount_rate",
    "expression": "{{input.quantity}} >= 10 ? 0.15 : 0.05"
}

Clean and Normalize Name

{
    "field": "clean_name",
    "expression": "$upper($trim({{input.name}}))"
}

Days Since Created

{
    "field": "days_since_registration",
    "expression": "$dateDiff({{input.created_at}}, $now(), \"days\")"
}

Notes

When pass_through_input: true, all original fields are preserved and new computed fields are added alongside them
When pass_through_input: false, only the fields listed in expressions appear in the output
Expression evaluation errors (division by zero, invalid types) result in null for that field, not a node failure
For complex logic that outgrows the expression engine, use the PHP Code node