BlueprintLab Tools
JAEN
All tools / CSV checker

CSV CHECK

Klaviyo historical event CSV checker

Check a historical-event CSV before importing it into Klaviyo.

Check CSV

🔒 Analysis runs in your browser. The CSV file itself is not uploaded to BlueprintLab.

Files are processed in your browser and are not sent to our server.

What this tool checks

Checks the 50 MB limit, Timestamp, Person//Email / Person//ID, email format, $event_id for duplicate timestamps, and numeric $value.

About this tool

Klaviyo historical event CSV checker is a free online utility from BlueprintLab Tools. Validate Timestamp, Person//Email / ID and $event_id before import.

Designed for small marketing and CRM tasks such as preflight checks before importing campaign or customer data.

No account is required. The tool is designed to complete the task directly in your browser with a short input → process → result flow.

How to use

  1. Enter or choose ＋ choose a csv file tap or click to choose. drag & drop also works on desktop..
  2. Enter the required values.
  3. Run the tool and review, copy, or use the result.

Related tools

Klaviyo profile / list CSV checkerCheck identifiers, duplicates and the 50 MB limit before list import.Google Ads Customer Match CSV checkerCheck headers, email, phone, address fields and encoding before upload.e-Hiden III CSV format checkerCheck encoding, delimiter, CSV syntax and signs of Excel tab conversion.CSV encoding & delimiter inspectorInspect likely encoding and comma, tab, semicolon or pipe delimiters.