How do I correctly join a separate date + time into ISO 8601 format?

[Bill_Maynard]

Hi guys!

Hoping someone can help me out because this has been driving me crazy.

I’m trying to create an RFC3339 (ISO 8601) datetime string in by joining a date and time coming from a Google Sheets form submission.

At the moment I have 2 set variable modules changing the different date and time input to the correct format separately:

But when I go to combine them together into a valid ISO 8601 string like:

2025-05-29T14:00:00Z By putting in the below:

I get the below issue

If it doesnt come back saying the variable value is empty, It’ll come back saying “2025-05-29” is not a valid date

I know the individual values are not empty and are in the correct format — so I’m guessing there’s a referencing issue or parsing quirk I’m missing.

Thanks in advance for any help!

[Probotic_Solutions]

Hi @Bill_Maynard,

Please try using the following formula:

{{formatDate(parseDate(trim(5.Date + space + 5.Time); "MM/DD/YYYY hh:mm A"); "YYYY-MM-DDTHH:mm:ss")}}Z

Make sure to replace:

• 5.Date with the date column from your sheet
• 5.Time with the time column from your sheet

I’ve attached a screenshot for reference.
If this helps, kindly mark it as a solution.

[Bill_Maynard]

Thank you so much!! Really appreciate it