Acceptable date and timestamp formats for profile and event properties reference
You will learn
Learn which date and time formats Klaviyo recognizes in event and profile properties sent through our APIs or in a CSV upload. These formats apply to property values. For the Create Event API’s time field, use an ISO 8601 timestamp, such as 2014-09-30T13:34:08Z.
Acceptable date and timestamp formats
For a date without a time, use YYYY-MM-DD, MM/DD/YYYY, or MM/DD/YY. Slash-separated dates use month/day/year. If you need a midnight timestamp, use 00:00:00 for the time. To keep a calendar date without adding a time, follow the CSV data-type guidance below.
If you do not include seconds on your timestamps, they will default to 0. For example, a timestamp of 2014-09-30 13:34 would be submitted to Klaviyo as 2014-09-30 13:34:00.
The following examples show supported timestamp formats for September 30, 2014. They use different times, timezone offsets, and levels of precision:
2014-09-30 13:34:08
2014-09-30 13:34:08+00:00
09/30/2014 13:34:08
09/30/14 13:34:08
09/30/2014 13:34
09/30/14 13:34
2014-09-30T13:34:08
2014-09-30 13:34:08.000001
2014-09-30T13:34:08.000001
2014-09-30 13:34:08.000001-04:00
1412098448 (Unix time in seconds)
If you need help reformatting your dates in a spreadsheet before converting it to a CSV file, head to our article, Formatting dates for CSV files.
Choose a data type for a CSV upload
When importing custom profile properties, use the Data Type column to select Date for timestamps, including Unix time in seconds. If a timestamp has no timezone offset, Klaviyo treats it as UTC.
When you import a date without a time, a default time of midnight UTC is applied when you select Date. This can shift the calendar date used by date-property triggered flows based on the profile’s timezone, or your account’s timezone when the profile’s timezone is unknown. For that reason, if you only have the date (no time) to upload, keep it in a supported date-only format and select Text.
Below is an example of what this CSV file may look like as you upload it with the correct date/time formats.
For more information on uploading a CSV file to Klaviyo, head to our article on how to add subscribers to an existing list.
Additional resources
- Formatting dates for CSV files reference
Learn how to edit dates in Excel and Google files to match the required date format in Klaviyo. This will make the process of uploading a CSV with customer data seamless and help you avoid upload errors.
- Klaviyo's default lists and segments reference
Learn about the default lists and segments provided for all new Klaviyo accounts. Once you complete the Klaviyo setup wizard, you will have several default lists and segments populated in your account. These lists and segments identify key groups of people within your account and are designed to help you get off on the right foot with your sending strategy. The pre-populated lists and segments are as follows: