Verify Email Addresses Instantly
Verify Email Addresses Instantly with Cleanlist's waterfall enrichment. Upload a CSV or connect your CRM — 30 free credits to start.
Start Free — 30 CreditsThe Problem
Every unverified email address you send to is a coin flip that can damage your domain reputation. ESPs like Google Workspace and Microsoft 365 now use machine learning to evaluate sender trustworthiness in real time. A single campaign with a 4%+ bounce rate can trigger spam folder routing for all subsequent emails from your domain — including transactional messages like password resets and invoices.
How Cleanlist Solves This
Cleanlist verifies individual email addresses through a multi-step process: DNS resolution confirms the domain exists and accepts mail, SMTP handshake simulates delivery without actually sending, pattern analysis detects catch-all configurations, and behavioral signals identify dormant mailboxes. The result is a binary Safe/Unsafe verdict with a granular confidence score for borderline cases.
The Real Cost of a Single Bounced Email Is $2.67, Not $0.01
The direct cost of a bounced email is negligible — a fraction of a cent in ESP sending fees. But the downstream cost is much higher. DMA research from 2025 found that each hard bounce contributes to sender reputation degradation that reduces inbox placement for subsequent sends. When modeled across an average 10,000-email campaign, each bounce reduces total delivered emails by 0.3-0.5 across future sends. At an average revenue-per-delivered-email of $0.54 (DMA benchmark for B2B), the cascading delivery loss from a single bounce costs approximately $2.67 in unrealized revenue over the following 30 days. For a list with a 5% bounce rate, that means 500 bounces create approximately $1,335 in invisible revenue loss — far exceeding the $50-100 it would cost to verify the entire list before sending. This is why verification ROI is typically 13-27x within the first campaign cycle.
Source: DMA Response Rate Report 2025; Cleanlist cost-modeling analysis
How It Works
Enter Email Addresses
Type a single email for instant verification, paste a batch of up to 500 addresses, or call the API endpoint with a single address for real-time checks within your application or form flow.
DNS & MX Record Resolution
The domain is checked for valid MX records, SPF configuration, and DMARC policy. Domains with no mail server configured are immediately flagged — no credit charged for obvious invalids.
SMTP Protocol Verification
Cleanlist opens a connection to the mail server and simulates the delivery handshake (HELO, MAIL FROM, RCPT TO) without sending any actual email. The server's response reveals whether the specific mailbox exists.
Advanced Detection Layers
Addresses on catch-all servers, greylisting servers, and rate-limited domains go through secondary verification: pattern analysis, historical delivery data from our provider network, and behavioral heuristics that identify abandoned inboxes.
Result Classification
Each address is classified: Deliverable, Undeliverable, Risky (catch-all or greylisted), or Unknown (server timeout). Risky addresses include a sub-score so you can set your own acceptance threshold.
Key Benefits
98% Email Accuracy
Real-time email verification catches bounces, catch-alls, and disposable addresses before they cost you.
15+ Data Providers
Waterfall enrichment across multiple providers means higher match rates than any single-source tool.
No Code Required
Upload a CSV, connect your CRM, or use the API. Works however your team prefers.
30 Free Credits
Start enriching immediately. No credit card, no sales call, no commitment.
Manual Process vs Cleanlist
| Feature | Manual | Cleanlist |
|---|---|---|
| Single-email verification speed | Send a test email and wait for bounce (hours) | Under 1 second via API |
| Greylisting handling | Cannot detect — appears valid | Automatic retry with delay to bypass greylisting |
| Accuracy on catch-all domains | Always reports 'valid' (false positive) | Risk-scored with historical pattern analysis |
| API integration | Not available — manual process | REST API with <1s response, webhook callbacks for batch |
| Cost per verification | $0 but high cost in bounces and reputation damage | From $0.005/email with volume pricing |
| Mailbox activity detection | No visibility | Dormant inbox flagging based on behavioral signals |
Frequently Asked Questions
How accurate is Cleanlist's data?
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Cleanlist achieves 98% email accuracy through real-time verification and cross-referencing across 15+ data providers. Every record is validated before delivery.
How many free credits do I get?
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Every new account starts with 30 free credits. Each credit processes one record (enrichment, verification, or lookup). No credit card required to start.
What data providers does Cleanlist use?
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Cleanlist uses waterfall enrichment across 15+ providers including major B2B data sources. The system automatically selects the best provider for each record to maximize match rates.
Can I connect my CRM?
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Yes. Cleanlist integrates with HubSpot, Salesforce, and other CRMs. Enriched data syncs back automatically. You can also upload CSV files or use the REST API.
How long does it take to verify my data?
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Most jobs complete in under 2 minutes for up to 10,000 records. Larger files are processed in batches with progress updates.
Does email verification actually send an email to the address?
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No. Cleanlist uses SMTP protocol simulation — it initiates the delivery handshake with the mail server but disconnects before any message is sent. The recipient never receives anything, and the verification leaves no trace in their inbox.
Can I verify a single email address in real-time on a signup form?
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Yes. Cleanlist's API returns verification results in under 1 second, making it suitable for inline form validation. Many customers use it to block disposable and invalid emails at the point of signup, reducing fraudulent accounts and improving list quality from day one.
Why do some verification tools give different results for the same address?
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Single-provider tools use one SMTP connection path, which can return different results depending on server load, greylisting, and rate limits. Cleanlist routes verification through multiple paths and providers, then aggregates results — this consensus approach eliminates the inconsistency you see with single-source tools.
Ready to verify your email addresses?
Start with 30 free credits. No credit card required. See results in under 2 minutes.
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