Nonprofits: How to Verify Donor Phone Numbers and Emails Before a Call or Text Campaign

Why donor data needs more care than a sales list

A sales team can replace a bad lead tomorrow. A nonprofit can't replace a donor who has given every December for fifteen years. Donor databases are old by design: they hold people who first gave long ago, through channels that no longer exist, with phone numbers written on reply cards and email addresses typed at a gala.

Over time:

• Landlines get disconnected as households drop them, and the number may be reassigned to someone else.
• Email accounts get abandoned, especially old ISP addresses.
• Formats pile up. Gift processing, event registrations and online forms each store numbers differently, so duplicates don't match and imports fail.

A phone bank that dials dead numbers wastes volunteer hours. A text campaign sent to landlines fails quietly. An appeal that bounces off a pile of old addresses can hurt delivery for the emails that matter.

Step 1: export and protect the numbers

Export the segment you're about to contact from your donor CRM: name, email, phone, last gift date. Before uploading:

• Don't open the file in Excel and save it. Excel strips leading zeros and turns long numbers into scientific notation. See CSV to Excel without losing leading zeros.
• If there are home, work and mobile columns, decide which one each campaign uses. The phone list segmenter splits rows by which columns are filled.

Step 2: validate every phone number

Upload the file to the verify page or the bulk phone number validator. Each number gets:

• Status: can it exist in its country's numbering plan?
• E.164 form: +13125550142, ready for any calling or texting platform.
• Country and numbering-plan type where the plan says (mobile, fixed line, toll-free, VoIP).

Numbers without a country code are read as US numbers. International donors need their code added first; the add or remove country code tool handles a column at once.

Old records often contain placeholders typed to get past a required field. The fake phone number checker flags 555-555-5555, repeated digits, straight runs and reserved fictional ranges.

Step 3: find out which numbers are mobiles

For a phone bank, landlines and mobiles both work. For text-to-give follow-ups or SMS appeals, only mobiles do. In the US and Canada, mobiles and landlines share area codes, so a format check alone can't tell them apart. A live carrier lookup returns the line type the carrier reports now, mobile, landline or VoIP, including numbers that were ported.

Spot-check with the free landline or mobile checker. For what happens when a text goes to a landline, see can you text a landline.

One caution: validation and carrier lookups tell you what the number is now, not who owns it. For US calling, the FCC's Reassigned Numbers Database tells you whether a number was disconnected after you got consent. It's worth knowing about for donor records that go back years.

Step 4: verify the emails

The same upload runs a live SMTP mailbox check on each email address, asking the donor's mail server whether the mailbox exists, without sending anything. Results:

• Valid: send.
• Invalid: remove from email sends and flag the record for an update. Don't delete the donor.
• Risky: a catch-all domain, a full inbox or a role address. Catch-alls are reported as risky, never guessed valid, with a likelihood grade (catch-all grading). For a donor who opened last year's appeal, send.
• Unknown: re-check before the next send.

More detail on the email side is in cleaning a nonprofit donor email list.

Step 5: consent and calling rules

Nonprofit status changes some rules but not all:

• Calls. US rules include exemptions for some calls made by tax-exempt nonprofits, particularly to residential landlines. They're narrower than many people assume.
• Texts. Automated texts to mobiles generally need prior consent. Text-to-give donors who texted your keyword have started a conversation, but what you may send afterwards depends on what they agreed to. Use clear opt-in and opt-out wording; the SMS compliance message generator drafts it.
• Email to Canadian or EU donors. CASL has specific provisions for registered charities, and GDPR applies in the EU and UK. The CASL consent checker and GDPR email consent checker help you sort a list.
• Calling hours. The TCPA calling hours checker works out the local time per number.

This isn't legal advice. Check with counsel before a new text programme.

Step 6: write the results back

Import the results into your CRM as fields: phone status, line type, email status and date checked. Then:

• Mark invalid emails and numbers as "needs update" instead of deleting them.
• Dedupe on E.164 numbers and lower-cased emails. Donors who gave through two channels often exist twice. Use remove duplicate phone numbers.
• Ask for updated details on the next gift receipt.

When to run it

Campaign	What to check
Year-end appeal	Full active donor list, emails and phones
Giving day	Mobiles for texts; emails for the reminder series
Phone bank	Phone validity and line type for the call list
Lapsed donor reactivation	Everything, since these records are the oldest

What it costs

• Free: 100 checks with a Google sign-in, no card.
• Starter, $9 a month: 2,500 emails a month.
• Pro, $39 a month: Unlimited email verification*, phone format checks on every row, the API and the MCP server.
• Pro + Phone, $49.99 a month: adds 5,000 live carrier lookups a month for mobile vs landline.

*Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.

See pricing.

More reading: phone line types explained, clean CRM phone numbers, prepare an SMS list for 10DLC.