Notion Date field accepts "now" but rejects all date manipulation functions - Invalid date in parameter 'start'

Questions
, ,
1

Hi everyone,

I’ve been building a scenario to automatically generate Notion database entries for specific dates each month, and I’ve hit a very specific issue with Notion’s date field that I can’t resolve.

The finding:

Passing now directly into Notion’s Date > Start Time field works perfectly — the entry is created with today’s date.

However, ANY date manipulation function wrapped around now fails with:

BundleValidationError — Validation failed for 1 parameter(s). Invalid date in parameter ‘start’.

Functions I’ve tried that all fail:

  • addDays(now; 0) — even adding zero days fails
  • addDays(now; 1)
  • addDays(now; 3.i - 1) (where 3.i is a Repeater counter)
  • addDays(parseDate(2.month_start; "YYYY-MM-DD"); 3.i - 1)
  • formatDate(addDays(now; 1); "YYYY-MM-DD")
  • formatDate(addDays(now; 1); "YYYY-MM-DDTHH:mm:ssZ")
  • startOf(addMonths(now; 2); "month")
  • setDay(now; 20)
  • now + (3.i - 1) * 86400000

All return the same error. Only now alone works.

What I’m trying to achieve:
I need to pass a calculated date (e.g. the 1st of a month two months from now, stepped through 31 days using a Repeater) into Notion’s Date field.

Question:
How do you pass a calculated or offset date into Notion’s Date > Start Time field in Make? Is there a specific function or approach that returns a date type that Notion’s module will accept?

Any help appreciated — this is the last piece of an otherwise working scenario!

3

Notion’s date field is picky about what format it actually accepts from Make — the module validation strips out the timestamp metadata that functions like addDays return, even though the raw value looks correct. Try wrapping your final expression in formatDate with the exact ISO format Notion expects, then map it to a text field first to verify what’s actually coming through before pointing it at the date field.