Clean, deduplicated, deliverable contact data — without the spreadsheet wrangling.

Plumbline takes your messy contact and mailing list exports and turns them into one reliable source of truth. Import from anywhere, and Plumbline verifies addresses, merges duplicates into a single golden record per contact, and flags real conflicts for a quick human decision instead of silently overwriting anything.

Address verification

Every address gets standardized and checked for deliverability before it ever reaches a mailing list.

Real duplicate detection

Matches get merged into one golden record. Genuine conflicts go to a quick human decision — nothing is silently overwritten.

Regions, segments & suppressions

Organize contacts by region, save reusable segments, and suppress recent customers from your next mailing.

A map of your whole list

See every contact plotted geographically, so you always know what you're actually mailing.

Want to talk it through first?

Tell us about your list and what you're trying to do — we'll follow up directly.