---
title: "Pavel Stoletov — EmailShield"
description: "CTO at EmailShield leading verification and deliverability engineering. Architected the multi-port SMTP pipeline, domain-grouped catch-all probe system, and self-hosted proxy infrastructure that EmailShield runs in production."
canonical: "https://emailshield.co/authors/pavel-stoletov"
last-updated: "2026-08-22"
---

> CTO at EmailShield leading verification and deliverability engineering. Architected the multi-port SMTP pipeline, domain-grouped catch-all probe system, and self-hosted proxy infrastructure that EmailShield runs in production.

EmailShield [EmailShield](https://emailshield.co/)

Pavel Stoletov

Author

# Pavel Stoletov

CTO | Email Verification & Deliverability Engineering

[LinkedIn](https://www.linkedin.com/in/pavel-stoletov-768426356/)

CTO at EmailShield leading verification and deliverability engineering. Architected the multi-port SMTP pipeline, domain-grouped catch-all probe system, and self-hosted proxy infrastructure that EmailShield runs in production.

## Articles by Pavel

### [Catch-All Email Verification: Why Most Verifiers Return "Unknown" and How to Validate Properly [2026]](https://emailshield.co/blog/catch-all-email-verification)

[Most email verifiers return "unknown" on 15-30% of B2B lists because catch-all domains accept every SMTP probe with a 250 response. Compare how EmailShield, ZeroBounce and MillionVerifier handle catch-all detection differently.](https://emailshield.co/blog/catch-all-email-verification)

[July 5, 2026](https://emailshield.co/blog/catch-all-email-verification)

### [Cold Email SPF, DKIM and DMARC Setup Guide [2026]](https://emailshield.co/blog/cold-email-spf-dkim-dmarc-setup-guide-2026)

[Complete 2026 setup guide for SPF, DKIM, and DMARC on cold email domains. DNS record syntax, the 10-lookup limit, the policy ramp from p=none to p=reject, validation playbook, and the verification step most operators skip.](https://emailshield.co/blog/cold-email-spf-dkim-dmarc-setup-guide-2026)

[July 6, 2026](https://emailshield.co/blog/cold-email-spf-dkim-dmarc-setup-guide-2026)

### [Email Verification API: Real-Time SMTP Validation for Developers [2026]](https://emailshield.co/blog/email-verification-api)

[How a production email verification API actually works: sub-2-second single validation for signup forms, webhook-driven bulk jobs, live multi-port SMTP handshakes, and Microsoft 365 API-level verification. Based on Q3 2026 EmailShield platform data across 8.19M verified addresses.](https://emailshield.co/blog/email-verification-api)

[July 10, 2026](https://emailshield.co/blog/email-verification-api)

### [Email Verification in Node.js: Real-Time Signup Validation Without False Positives [2026]](https://emailshield.co/blog/email-verification-node-js)

[DNS-only Node.js email verification libraries pass catch-all and Microsoft 365 addresses as valid, so signup lists still bounce 7%+. Here is how to run real SMTP-handshake email verification in Node.js with EmailShield's API and Node SDK at 99.8% verified accuracy.](https://emailshield.co/blog/email-verification-node-js)

[July 12, 2026](https://emailshield.co/blog/email-verification-node-js)

### [How Email Verifiers Work: Real SMTP Verification vs DNS-Only Lookups [Technical Guide 2026]](https://emailshield.co/blog/how-email-verifiers-work-smtp-vs-dns)

[A technical breakdown of how email verifiers work under the hood. Compare real SMTP handshakes vs DNS-only lookups, see why DNS-only tools cap at 91-94% accuracy, and learn how EmailShield's 4-stage pipeline hits 99.8% verified accuracy.](https://emailshield.co/blog/how-email-verifiers-work-smtp-vs-dns)

[July 8, 2026](https://emailshield.co/blog/how-email-verifiers-work-smtp-vs-dns)