DataDoctor

Runs entirely in your browser — no uploads, no saved snippets, no public links.

Paste a file, inspect the issues, export reviewed output.

Mailchimp import preflight

Mailchimp CSV Checker

Check email-list CSVs for required email columns, duplicates, invalid addresses and missing names.

Paste contacts CSV, load the contacts sample, or upload a local file.

Next workflow

Continue the preflight

HubSpot CSV Import Checker

Check another contact import target.

Google Contacts CSV Cleaner

Validate contacts with phone and identity checks.

CSV Cleaner

Export a cleaned contact list.

After the tool runs

Mailchimp CSV Checker review guide

Use the tool above first. The supporting notes below help you interpret the result, fix the right issues in the right order, and choose the next DataDoctor tool without pushing SEO content above the actual task.

Best input

checking Mailchimp audience CSV files for contact-level issues before list import.

Output to keep

Keep a before/after import file plus a short list of rows changed for the target platform.

Next check

Run a generic CSV data quality check before final upload when the platform-specific checker passes.

What it checks

Mailchimp CSV Checker for real data work

Mailchimp CSV Checker focuses on the rules a real platform usually enforces: required headers, identity fields, duplicate keys and value formats.

  • Email Address column
  • Duplicate emails
  • Invalid email addresses
  • Contacts missing names

Fix these first

Common errors to review before downstream work

Most failures come from small file issues that become expensive only after an API call, import job or spreadsheet cleanup. Fix blocking errors first, then re-run the same tool before moving forward.

  • Email column named unexpectedly
  • Duplicate subscribers
  • Malformed addresses
  • Rows with no personalization fields

Recommended workflow

Run the check in this order

Use the report to fix platform-blocking issues first. After those pass, run broader CSV checks for blanks, type drift and suspicious rows before uploading.

  1. Step 1

    Paste the Mailchimp CSV

  2. Step 2

    Run the checker

  3. Step 3

    Remove or merge duplicate emails

  4. Step 4

    Fix invalid addresses before upload

How to interpret a passing result

A pass means this specific preflight did not find the issues listed above. It is not a guarantee that the target system will accept every row, field, custom mapping or account-specific rule.

Platform presets catch common import rules, but account-specific mappings, custom fields and plan-specific limits can still reject rows.