RWS Docs

Interpolation replaces placeholders with actual values at runtime, enabling integrations that adapt to different contexts, time periods, and data.

Type	Syntax	Use Case
Simple Variables	`{{ variableName }}`	Insert values from parameters
DateTime	`{{ now.format(YYYY-MM-DD) }}`	Current date/time with formatting

When to use

Use interpolation when you need to:

Insert parameter values into API URLs or paths
Add dynamic dates to requests (today, yesterday, last week)
Reference dates from extraction datapoints
Generate file names with timestamps
Build parameterized query strings

Simple Variables

Replace placeholders with values from your integration’s parameters. The variable name must match exactly.

// Input
"users/{{ userId }}/orders"
// Params
{ "userId": "123" }
// Output
"users/123/orders"

Using datapoints with simple variables

To interpolate a datapoint value, add a query param with the datapoint field name. The param name becomes available as a variable.

// Query Params
{ "userId": "{{ userId }}" }
// Path
"users/{{ userId }}/orders"
// If datapoint has userId = "456", output becomes
"users/456/orders"

DateTime Interpolation

Insert current dates, calculate relative dates, and format output for API requirements. DateTime interpolation supports three prefixes:

Prefix	Description	Example
`now`	Current date and time	`{{ now.format(YYYY-MM-DD) }}`
`today`	Alias for `now`	`{{ today.format(YYYY-MM-DD) }}`
`date()`	Date from a data field	`{{ date(order.createdAt).format(YYYY-MM-DD) }}`

After the prefix, chain operations with dots. Date operations apply in the order they are written and can be repeated:

Operation	Description	Example
`add(1.day)`	Move forward in time	`{{ now.add(1.day) }}`
`plus(1.day)`	Alias for `add`	`{{ now.plus(1.day) }}`
`subtract(1.month)`	Move backward in time	`{{ now.subtract(1.month) }}`
`remove(1.month)` / `minus(1.month)`	Aliases for `subtract`	`{{ now.minus(1.month) }}`
`set(date.15)`	Set a unit to a value	`{{ now.set(date.15) }}`
`startOf(month)`	Jump to the start of a period	`{{ now.startOf(month) }}`
`endOf(month)`	Jump to the end of a period	`{{ now.endOf(month) }}`
`format(YYYY-MM-DD)`	Output format	`{{ now.format(DD/MM/YYYY) }}`
`timezone(UTC)`	Timezone for the date (`tz` also works)	`{{ now.tz(UTC) }}`
`locale(pt-br)`	Language for formatted names	`{{ now.locale(pt-br).format(MMMM) }}`

A misspelled or unsupported operation fails the request with a clear error instead of being silently ignored.

Format Patterns

Use .format(pattern) to control output. Patterns follow dayjs format tokens.

Pattern	Output Example
`YYYY-MM-DD`	2026-01-12
`DD/MM/YYYY`	12/01/2026
`YYYY-MM-DDTHH:mm:ss`	2026-01-12T15:30:00
`HH:mm:ss`	15:30:00
`MMMM D, YYYY`	January 12, 2026

Timezone Conversion

Use .timezone(tz) to evaluate the date in a specific timezone. The default timezone is America/Sao_Paulo. tz is an alias for timezone.

{{ now.timezone(UTC).format(YYYY-MM-DDTHH:mm:ss) }}
{{ now.timezone(America/New_York).format(YYYY-MM-DD) }}
{{ now.tz(Europe/London).format(HH:mm:ss) }}

Locale

Use .locale(name) to output formatted names (month names, weekday names) in another language. The default is English; pt-br is available. A locale that is not available falls back to English.

{{ now.locale(pt-br).format(MMMM) }} // novembro
{{ now.format(MMMM) }} // November
{{ now.locale(xx-yy).format(MMMM) }} // November (unavailable locale falls back to English)

format, timezone, and locale are context settings: they can appear anywhere in the chain and their position does not change the result.

Date Arithmetic

Add or subtract time using .add(amount.unit) and .subtract(amount.unit) — the amount and the unit are separated by a dot. plus is an alias for add; remove and minus are aliases for subtract. Available units: day, week, month, quarter, year, hour, minute, second (plural forms also work)

{{ now.subtract(1.day).format(YYYY-MM-DD) }} // Yesterday
{{ now.remove(7.days).format(YYYY-MM-DD) }} // One week ago (alias)
{{ now.add(1.month).format(YYYY-MM-DD) }} // Next month
{{ now.plus(1.month).format(YYYY-MM-DD) }} // Next month (alias)
{{ now.minus(1.quarter).format(YYYY-MM-DD) }} // One quarter ago (alias)
{{ now.subtract(1.month, 2.days).format(YYYY-MM-DD) }} // Several units in one call

Period Boundaries

Use .startOf(unit) and .endOf(unit) to jump to the boundary of a period. endOf resolves real month lengths, including leap years. Available units: day, week, isoWeek, month, quarter, year, hour, minute, second

{{ now.startOf(month).format(YYYY-MM-DD) }} // First day of this month
{{ now.endOf(month).format(YYYY-MM-DD) }} // Last day of this month (28/29/30/31)
{{ now.startOf(quarter).format(YYYY-MM-DD) }} // First day of the quarter
{{ now.endOf(year).format(YYYY-MM-DD) }} // December 31st

week starts on Sunday; use isoWeek for weeks that start on Monday:

{{ now.startOf(week).format(YYYY-MM-DD) }} // Sunday
{{ now.startOf(isoWeek).format(YYYY-MM-DD) }} // Monday

Setting Units

Use .set(unit.value) to pin a unit to an exact value, keeping everything else.

Unit	Value range	Example
`date`	1–31 (day of the month)	`set(date.15)` → the 15th
`day`	0–6 (0 = Sunday … 6 = Saturday)	`set(day.1)` → Monday of this week
`month`	1–12 (1 = January, matching `MM`)	`set(month.1).set(date.1)` → January 1st
`year` / `hour` / `minute` / `second`	—	`set(hour.9)` → 09:xx

{{ now.set(date.5).format(YYYY-MM-DD) }} // The 5th of this month
{{ now.set(date.1, hour.0).format(YYYY-MM-DD HH:mm) }} // Several units in one call

Operation Order

Date operations run left to right, so chaining reads exactly like what happens — and the same operation can appear more than once:

// Last day of THIS month, then one day forward = first day of next month
{{ now.endOf(month).add(1.day).format(YYYY-MM-DD) }}

// One day back first, then that month's last day
{{ now.subtract(1.day).endOf(month).format(YYYY-MM-DD) }}

{{ now.startOf(week).startOf(day).format(YYYY-MM-DD) }} // Compounding works too

Using Data Fields

Reference dates from your extraction datapoints with the date() function. Pass the field path as the argument.

{{ date(order.createdAt).format(YYYY-MM-DD) }}
{{ date(user.lastLogin).add(30.days).format(YYYY-MM-DD) }}
{{ date(invoice.dueDate).subtract(7.days).format(YYYY-MM-DD) }}

This is useful when you need to calculate dates relative to data values rather than the current time.

Full Example

A monthly extraction that always covers the previous calendar month, whatever the length of the month:

// Query Params
{
  "start_date": "{{ today.subtract(1.month).startOf(month).format(YYYY-MM-DD) }}",
  "end_date": "{{ today.subtract(1.month).endOf(month).format(YYYY-MM-DD) }}"
}
// Running on 2026-03-10 produces
{
  "start_date": "2026-02-01",
  "end_date": "2026-02-28"
}

And a longer chain, read left to right: go back one quarter, jump to its start, land on the Monday of that week, at 9:00, with the whole expression evaluated in UTC:

{{ today.subtract(1.quarter).startOf(quarter).startOf(isoWeek).set(hour.9).timezone(UTC).format(YYYY-MM-DDTHH:mm:ss) }}

When a parameter is missing

If a {{ parameter }} referenced in a URL, header, or body has no value at runtime, the request is not sent. It fails with a clear parsing error naming the missing parameter. An empty string counts as missing: sending it would produce a malformed request (e.g. /items//details) that the target API would misroute instead of reject. Parameter names are case-sensitive and must match the data field exactly.

Connections

Business Rules

Extract

Load

Rate Limit

Monitoring

Dynamic Parameters

When to use

Simple Variables

Using datapoints with simple variables

DateTime Interpolation

Format Patterns

Timezone Conversion

Locale

Date Arithmetic

Period Boundaries

Setting Units

Operation Order

Using Data Fields

Full Example

When a parameter is missing

​When to use

​Simple Variables

​Using datapoints with simple variables

​DateTime Interpolation

​Format Patterns

​Timezone Conversion

​Locale

​Date Arithmetic

​Period Boundaries

​Setting Units

​Operation Order

​Using Data Fields

​Full Example

​When a parameter is missing

When to use

Simple Variables

Using datapoints with simple variables

DateTime Interpolation

Format Patterns

Timezone Conversion

Locale

Date Arithmetic

Period Boundaries

Setting Units

Operation Order

Using Data Fields

Full Example

When a parameter is missing