Waterfall enrichment

Why a waterfall

Every data provider has gaps. One may be strong on US software companies, another on European manufacturers, a third on small agencies. Ask only one and every record outside its coverage stays empty. Ask all of them for every record and you pay several times for the same answer. A waterfall asks the next provider only where the one before came back empty or failed the check, so each record gets more than one try, and the providers after the first accepted answer never run.

How a waterfall runs

1. Start from what the row has. If the record already holds an email, check it first, and search only when it fails.
2. Ask the first provider. It reads the match key, usually the person's name and the company domain, and returns an answer or nothing.
3. Check the answer. For an email, a verifier asks the domain's mail server whether it would take that address.1
4. Stop or move on. An accepted answer is written to the row and the chain stops. An empty or failed one sends the row to the next provider.
5. Record the outcome. Keep which provider answered, or that every provider was asked and none did. If GDPR covers the person, you have to tell them where their data came from.2

Put the provider that is most accurate for your market first, and broader or cheaper ones after it. Re-test the order now and then on a sample of records whose emails you already know.

Where the check runs out

An email check is only as good as the mail server's answer. Some servers accept every address at the recipient step, because they take mail for any name or decide only once the message itself arrives, so the check learns nothing about the person.1 Verifiers call these catch-all domains. Decide in advance whether a catch-all answer stops your waterfall or sends the row on. Moving on rarely helps, since any other address on that domain comes back catch-all too.

In GetSales the Find work email column works this way. It asks one finder at a time, in the order you set, and stops at the first address that passes the verifier you pick, or at the first one found when you pick none. With a verifier, Accept catch-all emails is on by default. The row's own address can go first, checked at the verifier's rate. An address a finder delivers costs 1 credit, its check included, and a miss costs nothing. Each cell's Log shows what it tried.

Related

• Waterfall enrichment in GetSales: finders in your order, each address checked by the verifier you pick.
• Email finder: a work email from a name and a company.
• Email verification: check the addresses your list already has.
• Data enrichment: emails, person and company data, scores and first lines in one table.

Sources

1. Internet Engineering Task Force, RFC 5321: Simple Mail Transfer Protocol, section 7.3, October 2008. Read 28 October 2026.
2. European Parliament and Council of the European Union, Regulation (EU) 2016/679 (General Data Protection Regulation), Article 14, 27 April 2016. Read 28 October 2026.