Email list cleaning for nonprofit donor lists
Nonprofit donor lists are usually older than commercial ones and built from more sources: event registrations, a donation platform, a volunteer spreadsheet, and a decade of people who gave once.
The appeal that matters most often goes to the lapsed part of that list, which is also the part most likely to bounce. ZapBounce checks those addresses before the send with its own SMTP check, closes before DATA so no supporter receives anything, and never bills an address it couldn't get an answer on.
You pay for what the check finds: $5 for 1,000 addresses or $89 for 50,000, with 100 free checks every month and credits that never expire.
Why the year-end appeal is your riskiest send
It goes to everyone, including supporters who last gave in 2019. A decade-old address on a defunct provider bounces, the rate climbs past the threshold, and the appeal that funds next year's program gets filtered partway through.
A nonprofit rate on your sending platform comes with the same bounce limits as anyone else's. A suspension in the weeks your biggest appeal goes out can't wait for a support ticket.
Credits here come out of program budget, which is a real argument for checking the lapsed segment first rather than paying to recheck supporters who opened last month.
How the work gets done
The order that matters for nonprofits, rather than a generic checklist.
Verify the lapsed segment first
Anyone who hasn't given or opened in two years. That segment holds most of the risk, and checking it alone keeps the spend proportionate.
Use the free hundred to sample
A hundred checks a month, no card. Run a sample of the oldest records and you'll know whether the full list needs doing before spending anything.
Keep the unknowns
An unknown result means a server wouldn't answer, not that the supporter is gone. Deleting donor records to improve a percentage is a bad trade in a sector where winning a donor back costs more than keeping one.
Check registrations after every event
Event sign-up data is typed in a hurry on a phone. A small check after each event stops the main list degrading between appeals.
The hard cases in nonprofits, and how they come back
What it costs
A hundred free checks a month covers a first sample. A full clean of a 50,000-record donor database is $89, and credits never expire, so a pack bought before the year-end appeal still covers spring. Duplicates across merged sources are never billed, which matters on a list assembled from five places.
Every tier works the same way. Unknown results and duplicates are never billed, and credits do not expire.
Questions we get asked
What's the best way to clean an old donor list?
Verify the lapsed segment first, send catch-all and unknown rows separately, and suppress only the invalid ones. That order puts the spend where the bounce risk is and keeps every supporter you can still reach. A 50,000-record list costs $89 to check with ZapBounce.
What does it cost to clean a donor list?
$89 for 50,000 addresses and $139 for 100,000, at published pay-as-you-go prices. The first 100 checks each month are free with no card, and duplicates and unknowns are never billed.
Should I remove lapsed donors who come back catch-all?
No. Catch-all means the domain accepts everything, which is common and says nothing about that person. Segment them and read the bounce rate on that send.
We merged a partner's list. Is that a problem?
It carries spam-trap risk, because pristine traps look exactly like working mailboxes to any verifier. Verify it, send to it separately, and watch complaints closely.
Try it on your own list first
100 free checks a month, no card. Run a sample and read the unresolved count before you decide anything.