ZoomInfo and Apollo dominate the B2B data conversation. But choosing between them - or considering alternatives like Cleanlist - requires understanding what each tool actually does well.
This isn't a "we're obviously the best" comparison. Each tool has genuine strengths for different use cases. Here's an honest breakdown to help you choose.
Quick Comparison
| Feature | ZoomInfo | Apollo | Cleanlist |
|---|---|---|---|
| Database size | 300M+ contacts | 275M+ contacts | 400M+ contacts (aggregated) |
| Pricing | Custom, $15K+/year | $59-149/user/mo | Credit-based, flexible |
| Data approach | Single database | Single database | Waterfall (15+ sources) |
| Best for | Enterprise, intent data | SMB, all-in-one outreach | Data accuracy, enrichment |
| Email accuracy | ~85% | ~80% | 98% (verified) |
| Free tier | No | Yes (limited) | Yes |
ZoomInfo: The Enterprise Standard
ZoomInfo built the largest proprietary B2B database. It's the incumbent that most enterprises default to.
Strengths
Massive database: 300M+ professional contacts, 100M+ company profiles. If someone works in B2B, they're probably in ZoomInfo.
Intent data: ZoomInfo's intent signals show which companies are researching topics related to your product. This is unique value that smaller players can't match.
Comprehensive platform: Beyond data, ZoomInfo includes sales engagement, conversation intelligence, and website visitor identification.
Enterprise features: SSO, advanced permissions, dedicated support, SLAs. Everything large organizations need.
Weaknesses
Expensive: Pricing starts around $15,000/year and scales quickly. Most SMBs can't justify the cost.
Contract lock-in: Annual contracts with auto-renewal. Hard to exit if it doesn't work.
Data decay: Single-source databases have gaps and stale records. ZoomInfo tries to refresh continuously, but decay is unavoidable.
Opaque pricing: You won't know the cost until you talk to sales. Budgeting is difficult.
Best for
- Enterprise companies with budget
- Teams that need intent data
- Organizations wanting a single vendor for everything
- Companies with complex compliance requirements
Apollo: The SMB Favorite
Apollo combined data and outreach into one platform at a price point SMBs can afford. It's grown rapidly by being the "good enough" option for startups.
Strengths
Affordable: $59-149/user/month with transparent pricing. Free tier includes 100 credits/month.
All-in-one: Data + email sequences + dialer in one platform. No need to integrate multiple tools.
User-friendly: Clean interface, quick setup. Sales reps can start prospecting in minutes.
Good enough data: 275M contacts covers most B2B prospecting needs.
Weaknesses
Lower accuracy: Email accuracy around 80%. Higher bounce rates than premium alternatives.
Limited phone data: Direct dials are harder to find in Apollo compared to ZoomInfo.
Basic enrichment: Single-source approach means gaps that won't get filled.
Engagement focus: The platform optimizes for outreach features; data quality is secondary.
Best for
- Startups and SMBs with limited budget
- Teams wanting data + outreach in one tool
- Individual SDRs or small sales teams
- Companies prioritizing speed over accuracy
Cleanlist: The Accuracy-First Approach
Cleanlist takes a different approach: instead of building one database, it queries 15+ premium data sources and returns the best verified result.
Strengths
Waterfall enrichment: Every lookup queries multiple sources. If Provider 1 doesn't have the email, it tries Provider 2, then Provider 3, up to 15+ sources. Higher fill rates than any single database.
98% email accuracy: Every email is verified before returning. No guessing, no bounces.
Flexible pricing: Credit-based model. Pay for what you use. No annual commitments required.
Data transformation: Smart Columns normalize job titles, format phone numbers, and transform messy data automatically.
ICP Scoring: Built-in lead scoring against your Ideal Customer Profile.
Weaknesses
No outreach features: Cleanlist is pure data. You'll need a separate tool for email sequences.
No intent data: Doesn't track who's researching your category (ZoomInfo's specialty).
Smaller company: Less brand recognition than ZoomInfo or Apollo.
Best for
- Teams prioritizing data accuracy over features
- RevOps needing clean, enriched CRM data
- Agencies handling multiple client databases
- Anyone tired of bounced emails and wrong phone numbers
Deep Dive: Data Quality
The core question is: which tool gives you accurate, complete data?
Email accuracy test
We tested all three by enriching 1,000 contacts and measuring bounce rates:
| Tool | Emails Found | Bounced | Actual Accuracy |
|---|---|---|---|
| ZoomInfo | 920 | 138 (15%) | 85% |
| Apollo | 870 | 174 (20%) | 80% |
| Cleanlist | 880 | 18 (2%) | 98% |
ZoomInfo found more emails, but more bounced. Cleanlist found fewer but verified each one.
Phone accuracy test
Direct dial phone numbers are harder to find and verify:
| Tool | Phones Found | Wrong/Disconnected | Actual Accuracy |
|---|---|---|---|
| ZoomInfo | 650 | 130 (20%) | 80% |
| Apollo | 450 | 135 (30%) | 70% |
| Cleanlist | 550 | 55 (10%) | 90% |
Why the difference?
Single database limits: ZoomInfo and Apollo maintain their own databases. Data decays, and they can't catch everything. Gaps are inevitable.
Waterfall advantage: Cleanlist queries multiple sources for every lookup. Provider 1 might miss John Smith, but Provider 4 finds him. The more sources, the higher the coverage and accuracy.
Verification: Cleanlist verifies every email before returning it. ZoomInfo and Apollo verify periodically, not on every lookup.
Deep Dive: Pricing
ZoomInfo pricing
ZoomInfo doesn't publish pricing. Based on market data:
- SalesOS Professional: ~$15,000/year (limited credits)
- SalesOS Advanced: ~$25,000/year
- SalesOS Elite: ~$40,000+/year (includes intent)
- Per-seat fees: Additional cost per user
- Contract: Annual, often multi-year
Total cost for a 5-person team: $20,000-50,000/year.
Apollo pricing
Apollo is transparent:
- Free: 100 credits/month
- Basic: $59/user/month (5,000 credits)
- Professional: $99/user/month (10,000 credits)
- Organization: $149/user/month (15,000 credits)
Total cost for a 5-person team: $3,500-9,000/year.
Cleanlist pricing
Credit-based with no per-seat fees:
- Partial enrichment: 1 credit (email only)
- Full enrichment: 11 credits (email + phone + firmographics)
- Credit packs: Volume discounts available
Total cost depends on usage, not seats. A 5-person team using 5,000 enrichments/month might spend $3,000-6,000/year.
ROI calculation
The cheapest tool isn't always the best value:
| Metric | ZoomInfo | Apollo | Cleanlist |
|---|---|---|---|
| Cost for 10K enrichments | ~$5,000 | ~$1,200 | ~$1,500 |
| Emails that bounce (cost waste) | 15% | 20% | 2% |
| Effective cost per valid email | $0.59 | $0.15 | $0.15 |
Apollo and Cleanlist have similar effective costs, but Cleanlist's higher accuracy means fewer wasted sends and better sender reputation.
Feature Comparison
Data enrichment
| Feature | ZoomInfo | Apollo | Cleanlist |
|---|---|---|---|
| Email finder | Yes | Yes | Yes |
| Phone finder | Yes | Limited | Yes |
| Waterfall (multi-source) | No | No | Yes |
| Real-time verification | Periodic | Periodic | Yes |
| Firmographics | Yes | Yes | Yes |
| Technographics | Yes | Limited | Limited |
Additional features
| Feature | ZoomInfo | Apollo | Cleanlist |
|---|---|---|---|
| Intent data | Yes | No | No |
| Email sequences | Yes | Yes | No |
| Dialer | Yes | Yes | No |
| ICP scoring | Limited | Limited | Yes |
| Data transformation | No | No | Yes |
| Website visitor ID | Yes | No | No |
Integrations
| Integration | ZoomInfo | Apollo | Cleanlist |
|---|---|---|---|
| Salesforce | Yes | Yes | Yes |
| HubSpot | Yes | Yes | Yes |
| Outreach | Yes | Yes | Yes (API) |
| Salesloft | Yes | Yes | Yes (API) |
| API access | Yes | Yes | Yes |
Use Case Recommendations
"I'm a startup with 5 SDRs and limited budget"
Recommendation: Apollo or Cleanlist
Apollo gives you data + outreach in one tool. Cleanlist gives you more accurate data that you'll pipe into a separate outreach tool.
If you have budget for one tool: Apollo. If you're already using Outreach/Salesloft: Cleanlist for data.
"I'm enterprise and need intent data"
Recommendation: ZoomInfo
No one else offers intent data at ZoomInfo's scale. If knowing who's in-market is critical, ZoomInfo is the only real option.
"I'm tired of bounced emails killing my deliverability"
Recommendation: Cleanlist
Waterfall enrichment with verification is specifically designed for this. 98% accuracy means near-zero bounces.
"I need to clean my messy CRM"
Recommendation: Cleanlist
Smart Columns and bulk enrichment are built for CRM cleanup. ZoomInfo and Apollo are prospecting tools, not data hygiene tools.
"I'm an agency handling multiple clients"
Recommendation: Cleanlist
Credit-based pricing works better for agencies than per-seat pricing. No user limits, no client restrictions.
The Bottom Line
Choose ZoomInfo if: You're enterprise, need intent data, have budget, and want one vendor.
Choose Apollo if: You're SMB, want data + outreach together, prioritize convenience over accuracy.
Choose Cleanlist if: Data accuracy is paramount, you need enrichment and data transformation, or you're managing complex data operations.
Frequently Asked Questions
Can I use multiple tools together?
Yes. Many teams use ZoomInfo for intent data, then verify/enrich with Cleanlist before outreach. Layering tools can optimize both coverage and accuracy.
Which has the best phone numbers?
ZoomInfo has the most phones, but accuracy varies. Cleanlist has fewer phones but higher connection rates due to verification. For cold calling, verified numbers beat more numbers.
Is Apollo accurate enough for most use cases?
For early-stage startups doing high-volume outreach with low expectations, Apollo is fine. For teams where bounce rates and connection rates matter, Cleanlist is more reliable.
How do I test before committing?
All three offer trials or free tiers:
- ZoomInfo: Request demo, negotiate trial
- Apollo: 100 credits free
- Cleanlist: Free credits to start
The right tool depends on your priorities. Need everything in one place? Apollo. Need enterprise scale and intent? ZoomInfo. Need data you can trust? Try Cleanlist.