Looks like the function is actually called JSONTIME2EXCEL. Also, I’m just getting a #VALUE error for this formula, which I expected would work: =JSONTIME2EXCEL(“2021-12-31T03:00:00Z”), which is valid ISO8601.
Hi phraktle,
Thank you, I will see that the typo is corrected 
It seems, that the function in its current version supports only the following syntax:
YYYY-MM-DDThh:mm:ss.sssZ
If you add three zeros to your current string you should be good.
Try:
=JSONTIME2EXCEL(LEFT(B8,19)&".000Z")
With B8 = 2021-12-31T03:00:00Z
Further, I will open a feature request for the function to support further spellings.
Cheers
Tizian
Thanks! It’s not quite as simple as appending that suffix, since some timestamps do have a millisecond component (between zero and 3 digits) Anyway, it would be great if the function could parse all ISO8601 compliant timestamps.
You could also add the LEN() function to figure out the character amount and based on that use LEFT().
Anyhow, you are right, it would make a lot of sense to support the iso8601.