B2B contact databases are assembled from public web sources, business registries, contributed data and partner networks, then continuously verified through automated checks and campaign feedback. Records decay at roughly 2–3% per month through job changes alone, which is why refresh cadence matters more than headline record count.
Where the data comes from
No single source produces a usable B2B index. Databases are assembled from several streams and reconciled, which is why two vendors quoting similar record counts can differ enormously in accuracy.
- Public web sources. Company websites, team pages, press releases, professional profiles and published directories.
- Business registries. Statutory filings that establish company existence, size band, registered address and corporate structure.
- Contributed data. Records supplied by participating organisations under a data-sharing arrangement.
- Partner networks. Publisher and event networks where contacts have provided details in exchange for content.
- Campaign feedback. Bounce, response and correction signals from live campaigns, which is the most valuable stream and the one only operating vendors have.
Why records decay and how fast
B2B contact data is perishable in a way consumer data is not. People change jobs, companies restructure, email conventions change after acquisitions, and job titles get renamed in reorganisations. Industry estimates for B2B record decay cluster around 2 to 3% per month from job changes alone, which compounds to a substantial share of any static file within a year.
This is the single most important thing to understand about buying data. A list purchased once and used for eighteen months is not the same asset it was on day one, and the degradation is invisible until bounce rates spike.
What verification actually means
‘Verified’ is used loosely across the industry. Ask what it means specifically, because the answers differ enormously in value.
| Verification method | What it confirms | Strength |
|---|---|---|
| Syntax and domain check | The address is formatted correctly and the domain exists | Weak |
| Mail server validation | The mailbox accepts connections | Moderate |
| Cross-source corroboration | Multiple independent sources agree on the record | Good |
| Recent campaign delivery | The address accepted a real message recently | Strongest |
| Human verification | A person confirmed the record | Strong but expensive, used selectively |
A vendor claiming 95% accuracy without describing the method is quoting a syntax check. Vendors running live campaigns can quote delivery-confirmed accuracy, which is a materially different claim.
Filter granularity matters more than volume
A database of 200 million records that can only filter by industry and company size is less useful than one of 100 million that filters by job function, seniority, technology stack and geography down to city level.
The reason is that B2B targeting is committee targeting. You are not looking for ‘people at manufacturing companies’ — you are looking for the quality manager, the commercial director and the procurement lead at manufacturing companies of a specific size running a specific system in three specific markets. Volume without granularity cannot express that.
What to check before you buy
- Ask for a match count against your actual ICP filters before discussing price. If the count is small, nothing else matters.
- Request a sample file and spot-check it yourself. Pick twenty records and verify them manually. This takes an hour and predicts everything.
- Ask what verification means specifically and when the records were last checked.
- Ask about refresh cadence. A one-off extract decays; scheduled re-extracts do not.
- Ask for the compliance basis for your target geographies, in writing.
- Ask what happens when records bounce. Credit and replacement policy tells you how confident the vendor is.
Compliance is geography-specific, not vendor-specific
No database is ‘GDPR compliant’ as a property of the data. Compliance is a property of your intended use in a specific jurisdiction. The same record may be lawfully usable for B2B outreach in the United States under CAN-SPAM and require a documented legitimate-interest assessment in the European Union.
What a vendor can supply is the consent or lawful basis documentation, suppression list handling and regional opt-out mechanics. What they cannot do is make your campaign compliant by assertion. If a vendor claims blanket compliance without asking where you intend to send, that is a warning sign.