Check Klaviyo date and timestamp formats before import

Dates are one of the easiest fields to corrupt during a spreadsheet export because the visible cell and the serialized CSV value can differ.

Why dates become risky

Spreadsheet apps can silently reinterpret dates, drop timezone context or export locale-specific values. A destination Date property may then receive a string Klaviyo cannot parse as intended.

What ReadyRows checks

ReadyRows identifies likely Date columns and flags non-empty values that do not match its accepted Klaviyo-oriented date/timestamp patterns. It deliberately avoids converting ambiguous dates such as 03/04/2026 automatically.

When to review manually

If day and month order cannot be inferred safely, verify the source locale and the destination property type before changing the file. For historical event imports, also verify the required timestamp structure in Klaviyo documentation.

Official reference

Klaviyo documents the relevant import rule in its historical event import guide.

ReadyRows is an independent tool and is not affiliated with Klaviyo. Import rules can change; confirm account-specific behavior in the platform's official documentation.