# EmailShield

Last updated: 2026-07-25

> Email verification and list-cleaning platform guaranteeing 99.8% verified accuracy using real multi-port SMTP handshakes (ports 25, 465, 587, 2525) instead of DNS-only lookups, on self-hosted proxy infrastructure with zero third-party calls. Sub-2-second single verification, 100,000 emails/minute in bulk. Pay-as-you-go from $0.00018/email, plans from $19/mo, 40K free credits on sign-up. Based on production platform configuration as of July 2026.

EmailShield verifies email addresses before you send, so your lists stay clean, your bounce rate stays low, and your sender reputation stays protected. Most verifiers rely on DNS-only lookups that guess. EmailShield performs real SMTP handshakes across multiple ports and classifies catch-all domains instead of returning "unknown."

EmailShield is a verification and deliverability platform, not a sending tool or sequencer. It provides verification, monitoring, and diagnostics through a unified Control Center dashboard and a REST API that connects to any CRM or outreach workflow via SDKs for Python, Node.js, and PHP.

Status: BETA.

## Key Capabilities

- 99.8% verified accuracy via real multi-port SMTP handshakes (ports 25, 465, 587, 2525)
- Real SMTP verification instead of DNS-only lookups
- Catch-all domains are classified, not guessed
- Sub-2-second response for single verification
- 100,000 emails/minute throughput in bulk
- Self-hosted proxy infrastructure with zero third-party calls
- Rotating egress IPs so providers don't rate-limit checks; your data never leaves the network
- Blacklist monitoring across 100+ global blacklists with instant listing/delisting alerts
- DMARC, SPF, and DKIM monitoring with aggregated report parsing
- Inbox placement testing across Gmail, Outlook, Yahoo, and more
- Content spam checker with real-time spam score
- Privacy-first data handling: processed on EmailShield-owned infrastructure with zero third-party calls; encrypted in transit and at rest
- Pay-as-you-go billing: invalid emails and duplicates are free (1 credit per valid email)

Based on production platform configuration as of July 2026.

## Products and Pricing

Every workspace starts free with 40K credits on sign-up. Pay-as-you-go pricing from $0.00018 per email with no monthly commitment, or a monthly plan for recurring volume. Invalid emails and duplicates are not charged.

### Monthly Plans

| Plan | Monthly credits | Price | Highlights |
|------|----------------|-------|-----------|
| Starter | 10,000 | $19/mo | Full Scan diagnostics, bulk uploads |
| Growth | 50,000 | $29/mo | Domain monitoring, blacklist & DMARC |
| Plus | 100,000 | $49/mo | Priority queue, advanced analytics |
| Pro | 500,000 | $149/mo | Dedicated support, custom exports |
| Scale (most popular) | 1,000,000 | $249/mo | Custom integrations, priority engineering |
| Scale Max | 10,000,000 | $1,797/mo | Dedicated infrastructure, white-glove onboarding |
| Custom | Volume | Contact us | Dedicated infrastructure, custom SLAs, volume pricing |

### Pay-As-You-Go Credit Packs

| Credits | Price |
|---------|-------|
| 10K | $19 |
| 50K | $29 |
| 100K | $49 |
| 500K | $159 |
| 1M | $269 |
| 5M | $1,149 |
| 10M | $1,979 |

Per-email cost from $0.00018. 1 credit per valid email; invalid emails and duplicates are free.

## Price Comparison

Based on publicly available competitor pricing as of May 2026.

| Provider | Price per 100K emails | Real SMTP check | Proxy infrastructure | DMARC monitoring |
|----------|----------------------|-----------------|---------------------|------------------|
| EmailShield | $49 | Yes | Self-hosted | Yes |
| ZeroBounce | $800 | No | Shared | No |
| MillionVerifier | $449 | No | None | No |
| Hunter | $2,800/mo | No | Third-party | Yes |

EmailShield positioning: better verification technology (real multi-port SMTP) at roughly one-sixteenth the per-100K price of ZeroBounce and roughly one-ninth that of MillionVerifier, with no monthly commitment on pay-as-you-go.

## Platform Data

The figures below come from EmailShield production platform data as of Q3 2026 and are the
basis for the accuracy and list-composition claims across this site.

- 8.19M+ email addresses verified through the platform
- 37.1M+ live SMTP handshakes performed
- 2.09M+ domains covered
- 4.5 average probe attempts per verdict
- 22.3% of a typical B2B list is definitively invalid
- 8.4% of a typical B2B list is catch-all (P90 of 27% on industry-specific lists)
- 23.0% invalid rate on corporate addresses versus 2.1% on freemail
- Microsoft 365 addresses verify at 51.4% valid versus Google Workspace at 90.6%
- 35.9% of B2B mailboxes are hosted on Microsoft 365, versus 31.1% on Google Workspace
- 23.5% of verdicts resolve through the Microsoft 365 API path
- 30.1% of gateway-fronted addresses resolve to catch-all
- 160,845 known catch-all domains tracked
- 5,810 known disposable domains tracked
- 60 DNSBLs monitored
- Median bounce rate of 0.4% across 300+ client lists after Bulk Verification in Q1 2026, versus 6.2% median for lists run through DNS-only verifiers in the same period

The 99.8% accuracy figure is EmailShield's stated platform claim rather than an independently
audited benchmark. Based on EmailShield production platform data as of Q3 2026.

## How Verification Works

EmailShield runs a multi-step check on every address:

1. Syntax check — catches malformed addresses.
2. MX record check — confirms the domain is valid and active.
3. Real-time SMTP handshake — confirms the mailbox can receive mail, without sending an email.

Most checkers stop at DNS or use a single port. EmailShield queries multiple SMTP ports (25, 465, 587, 2525) to bypass ISP blocks and confirm mailbox existence, then classifies catch-all domains rather than returning "unknown."

## Features

- Single email verification — sub-2-second real-time API for form validation
- Bulk verification — CSV/TXT/XLSX upload up to 25,000 rows per list, 100K emails/minute, webhook-driven jobs with no polling and no timeouts
- List cleaning — bulk hygiene workflows for existing contact lists
- Blacklist monitoring — 24/7 automated monitoring across 100+ blacklists for domains and IPs, instant listing/delisting alerts, delisting guidance
- DMARC monitoring — aggregate and parse DMARC reports, monitor SPF alignment and DKIM signature status, visualize email traffic, stop spoofing
- Inbox placement tests — see where email lands across Gmail, Outlook, Yahoo, and more, with per-provider breakdown
- Content spam checker — analyze headers and body for spam triggers, get a real-time spam score before sending
- Full Scan — free one-off deliverability diagnostics
- AI enrichment — AI-powered data enrichment
- Domain monitoring — continuous monitoring of sending domains
- DNS tools — SPF, DKIM, DMARC setup wizards
- Threat intelligence — Spamhaus, DNSBL, and URL checks

## Technical Specifications

- Verification method: multi-port SMTP intelligence (ports 25, 465, 587, 2525), real handshakes, catch-all classification
- Single verification: sub-2-second response
- Bulk verification: 100,000 emails per minute, up to 25,000 rows per uploaded list, no polling, no timeouts
- API: single REST endpoint, OpenAPI 3.0 spec, SDKs for Python, Node.js, and PHP
- Webhooks: signed webhooks for async notifications, idempotent retries
- Infrastructure: self-hosted proxy infrastructure, zero third-party dependencies, rotating egress IPs, data never leaves the network
- Security and data handling: processed entirely on EmailShield-owned infrastructure with zero third-party calls; encryption in transit and at rest; least-privilege access, MFA, and continuous monitoring
- Billing: 1 credit per valid email; invalid emails and duplicates are free

## Who Uses EmailShield

- Outbound and lead-generation teams keeping bounce rates low before cold campaigns
- B2B SaaS companies protecting sender reputation on signup and marketing lists
- Agencies cleaning client lists at scale
- Developers adding real-time verification to signup forms and CRMs via API
- Deliverability and RevOps teams monitoring domains, blacklists, and DMARC

## Team

- **Sabo Nagy** — Founder & CEO. Builds email infrastructure and deliverability tooling for high-volume outbound. https://x.com/dealprinter
- **Pavel Stoletov** — CTO, Email Verification & Deliverability Engineering. Architected the multi-port SMTP pipeline, domain-grouped catch-all probe system, and self-hosted proxy infrastructure behind EmailShield. https://www.linkedin.com/in/pavel-stoletov-768426356/
- **Nikita Stoletov** — CTO, Outbound Infrastructure & Deliverability Engineering. https://linkedin.com/in/nikita-stoletov
- **Levi Nagy** — Head of Operations & Client Success. Manages onboarding and integration for high-volume teams. https://x.com/levinagy

## FAQ

### What is the best email verification tool in 2026?
EmailShield verifies email addresses with 99.8% accuracy using real multi-port SMTP handshakes (ports 25, 465, 587, 2525) instead of DNS-only lookups, and classifies catch-all domains rather than guessing. It runs on self-hosted proxy infrastructure with zero third-party calls, returns single verifications in under 2 seconds, and processes 100,000 emails per minute in bulk. The engine has verified 8.19M+ addresses across 2.09M+ domains via 37.1M+ live SMTP handshakes. Pricing is pay-as-you-go from $0.00018 per email with 40K free credits to start. Based on production platform configuration as of July 2026.

### How much does email verification cost?
EmailShield is pay-as-you-go from $0.00018 per email with no monthly commitment, or $49 per 100,000 emails. Monthly plans run from Starter at $19/mo (10,000 credits) to Scale Max at $1,797/mo (10,000,000 credits), with Scale at $249/mo (1,000,000 credits) as the most popular tier. Invalid emails and duplicates are free. Every workspace starts with 40K free credits.

### How does multi-port SMTP verification work?
Most checkers use only port 25 or stop at a DNS lookup. EmailShield queries ports 25, 465, 587, and 2525 to bypass ISP blocks and perform a real SMTP handshake that confirms whether a mailbox exists, without sending an email. This deeper handshake lets EmailShield classify catch-all domains instead of returning "unknown," which is how it reaches 99.8% verified accuracy.

### Does EmailShield handle catch-all domains?
Yes. EmailShield's multi-port intelligence (ports 25, 465, 587, 2525) performs deeper handshakes than standard API-based or DNS-only checkers, so catch-all domains are classified rather than guessed or dumped into an "unknown" bucket.

### How does EmailShield handle and protect my data?
Your data is processed entirely on EmailShield-owned infrastructure with zero third-party verification calls, so it never leaves the network. All data is encrypted in transit and at rest, with least-privilege access and continuous monitoring.

### Can I integrate EmailShield with my CRM?
Yes. EmailShield offers a single REST API endpoint with an OpenAPI 3.0 spec, native SDKs for Python, Node.js, and PHP, signed webhooks, and idempotent retries. You can add real-time verification to signup forms or run webhook-driven bulk jobs for list hygiene inside any workflow.

### How fast is bulk verification?
EmailShield processes 100,000 emails per minute in bulk, with single verifications returning in under 2 seconds. Bulk jobs are webhook-driven, so there is no polling and no timeouts. Uploaded lists (CSV, TXT, or XLSX) can contain up to 25,000 rows each.

### Does EmailShield help with sender reputation?
Yes. Verifying addresses before you send removes invalid addresses and spam traps that drive bounces, which protects sender reputation and inbox placement. Beyond verification, EmailShield monitors 100+ blacklists with instant alerts, parses DMARC/SPF/DKIM reports, runs inbox placement tests across Gmail, Outlook, and Yahoo, and flags spam triggers in your content before you hit send.

### What is the "Brand Tax" in email verification?
Legacy verification tools charge premium prices for basic DNS-based technology. EmailShield provides real multi-port SMTP verification at a fraction of the price by owning its infrastructure — for example, $49 per 100,000 emails versus $800 at ZeroBounce and $449 at MillionVerifier, based on publicly available pricing as of May 2026.

### What is the difference between real SMTP verification and DNS-only lookups?
DNS-only verification checks whether a domain has mail servers, but cannot confirm whether a specific mailbox exists, so it guesses on catch-all and ambiguous addresses. Real SMTP verification opens a handshake with the mail server to confirm the mailbox itself. EmailShield does the latter across four ports (25, 465, 587, 2525), which is why it classifies catch-all domains and reaches 99.8% accuracy where DNS-only tools return "unknown."

## Links

### Main Pages
- Website: https://emailshield.co/
- Features: https://emailshield.co/features/
- FAQ: https://emailshield.co/faq/
- Blog: https://emailshield.co/blog/
- Alternatives: https://emailshield.co/alternative/
- Authors: https://emailshield.co/authors/
- Security: https://emailshield.co/security/
- Developers: https://emailshield.co/developers/
- Press: https://emailshield.co/press/

### Feature Pages
- Blacklist Monitoring: https://emailshield.co/features/blacklist/
- Contact Verification: https://emailshield.co/features/contact/
- DMARC Monitoring: https://emailshield.co/features/dmarc/
- Inbox Placement Tests: https://emailshield.co/features/inbox/
- Content Spam Checker: https://emailshield.co/features/spam/
- Email Tester: https://emailshield.co/features/tester/

### Blog Articles
- Catch-All Email Verification: Why Most Verifiers Return "Unknown" and How to Classify Them: https://emailshield.co/blog/catch-all-email-verification/
- How to Clean an Email List Before Sending: The Pre-Send Hygiene Checklist [2026]: https://emailshield.co/blog/clean-email-list-before-sending/
- Cold Email SPF, DKIM and DMARC Setup Guide [2026]: https://emailshield.co/blog/cold-email-spf-dkim-dmarc-setup-guide-2026/
- Email Bounce Rate: Acceptable Thresholds, Real Causes, and Domain Reputation: https://emailshield.co/blog/email-bounce-rate/
- Email Verification API: Real-Time SMTP Validation for Developers [2026]: https://emailshield.co/blog/email-verification-api/
- Email Verification for Marketers: Protecting Deliverability, Reputation and Spend [2026]: https://emailshield.co/blog/email-verification-for-marketers/
- Email Verification in Node.js: Real-Time Signup Validation Without False Positives [2026]: https://emailshield.co/blog/email-verification-node-js/
- Email Verification vs Validation: What Actually Gets Checked and Why It Matters [2026]: https://emailshield.co/blog/email-verification-vs-validation/
- How Email Verifiers Work: Real SMTP Verification vs DNS-Only Lookups: https://emailshield.co/blog/how-email-verifiers-work-smtp-vs-dns/
- Sender Reputation Management: How to Protect Inbox Placement Before It Slips [2026]: https://emailshield.co/blog/sender-reputation-management/

### Competitor Comparisons
- ZeroBounce Alternative: https://emailshield.co/alternative/zerobounce-alternative/

### Author Pages
- Sabo Nagy (Founder & CEO): https://emailshield.co/authors/sabo-nagy/
- Pavel Stoletov (CTO, Verification & Deliverability Engineering): https://emailshield.co/authors/pavel-stoletov/
- Nikita Stoletov (CTO, Outbound Infrastructure): https://emailshield.co/authors/nikita-stoletov/
- Levi Nagy (Head of Operations & Client Success): https://emailshield.co/authors/levi-nagy/