How to Clean an Email List Locally with a Free Open-Source Node CLI

Description and use

The email‑list‑cleaner CLI cleans email lists locally by validating syntax, checking MX records, flagging disposable and role accounts, and suggesting typo fixes, all without sending data externally.

Problem

Bounces hurt sender reputation and many list verification services require uploading contacts to a third party.

Outcome

The tool removes invalid syntax, checks MX records via DNS, flags disposable and role accounts, suggests typos, and deduplicates case‑insensitively, producing a cleaned CSV without sending data outside the machine.

Workflow

• Run npx github:5012763083a-oss/email-list-cleaner contacts.csv -o cleaned.csv
• Optionally specify --column to target a specific CSV column
• Use --no-mx for fully offline operation
• Use --no-dedupe to keep duplicates
• Open cleaned.csv in a spreadsheet
• Filter by status column: drop 'invalid', review 'risky', fix 'didYouMean' suggestions
• Export final list for use

Evidence

Bounces hurt sender reputation, and many "list verification" services require uploading your contacts to a third party.

Source

Nothing in your list leaves your machine. The only network traffic is DNS lookups for the domains.

Source

The free edition processes the first 500 rows per file.

Source