Cognism is the European challenger to ZoomInfo - built on GDPR-first data with phone-verified mobile numbers and DNC list suppression. This review covers what Diamond Data actually delivers, email accuracy rates, and whether the enterprise price tag is justified.
Phone-verified mobile numbers. Human callers confirm each number is correct before it enters the Diamond tier. 87%+ connect rate stated vs 50-60% for standard mobile data.
Cognism scrubs numbers against Do Not Call registers for UK, Germany, France, USA (TCPA), Australia, Canada, Ireland, and others before including them in the database. Reduces legal exposure for phone outreach.
Partnership with Bombora provides buyer intent signals - companies showing research activity for specific categories. Available on Enterprise plans.
Bulk enrich Salesforce and HubSpot records with current contact data. Identifies stale contacts and updates them without manual lookup.
Reveal contact data directly on LinkedIn profiles and company websites. Integrates with Salesforce, HubSpot, and Outreach without leaving the browser.
Strongest B2B database for UK, Germany, France, DACH, Benelux, and Nordics. Coverage thins considerably for APAC and Latin America - ZoomInfo is stronger there.
20,000 Cognism-sourced contacts verified via BounceZero (Q1-Q2 2026). EU-focused dataset; UK and DACH contacts.
Cognism email accuracy (79%) is slightly better than Apollo (73-78%) but comparable with ZoomInfo (78-82%). The catch-all rate (12.4%) is lower than average for B2B providers, reflecting Cognism stronger data hygiene practices.
Important: Cognism email marking vs deliverability
Cognism marks addresses as verified when its own SMTP checks pass. However, SMTP verification does not detect catch-all domains or Microsoft 365 blocks. Run all Cognism exports through BounceZero before any campaign - particularly for M365-heavy industries (financial services, professional services) where our JMAP-based verification catches invalids that SMTP misses.
| Feature | Cognism | ZoomInfo | Apollo.io |
|---|---|---|---|
| Email accuracy | 79% | 78-82% | 73-78% |
| Mobile number accuracy | 87%+ (Diamond) | 75-80% | 60-70% |
| European data quality | Strongest | Good | Limited |
| US data quality | Good | Strongest | Good |
| DNC list suppression | Yes (8+ countries) | US only | No |
| GDPR compliance stance | Strong | Moderate | Basic |
| Intent data | Bombora (Enterprise) | Native (all plans) | Native (all plans) |
| Technographic data | Limited | Comprehensive | Good |
| CRM enrichment | Yes | Yes | Yes |
| Pricing (starting) | ~$15K/year | ~$15K/year | $49/month |
| Free trial | No | No | Free plan |
| Best for | EU outbound, phone-first GTM | US enterprise, technographics | Price-conscious, volume email |
Cognism EU data coverage and DNC compliance is unmatched for UK, Germany, France, and DACH market outbound. If your territory is European, Cognism is the strongest choice in this tier.
Diamond Data mobile numbers (87%+ connect rate) are the best-in-class for cold calling. Teams running 80+ dials per day see meaningful lift from Diamond vs standard mobile data.
Regulated industries (financial services, healthcare, legal) where DNC violations create legal risk. Cognism DNC scrubbing reduces that exposure across multiple jurisdictions.
At $15K+/year, Cognism is not accessible below Series A. Apollo + BounceZero achieves comparable email deliverability at under $600/year.
ZoomInfo has deeper US contact coverage, technographic data, and buyer intent signals than Cognism. For pure North American outbound, ZoomInfo is stronger.
If you do not cold call, Diamond Data adds no value. The email accuracy is good but not worth the Cognism premium over Apollo plus verification.
Cognism verification misses catch-alls and M365 blocks. Run exports through BounceZero to catch the remaining 20% before campaigns. 100 free credits, 8 minutes per 1,000 contacts.
Apollo, ZoomInfo, Lusha and Cognism all have accuracy gaps - verify exports before sending
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