Email Deliverability Masterclass for Newsletters – SPF, DKIM, DMARC & Warm-Up with Anthony from Mission Inbox | Episode 4 | The LetterStack Podcast

Hitting the primary inbox (not spam or promotions) is make-or-break for every newsletter and cold-email campaign. In Episode 4 of the LetterStack Podcast, Renga sits down with Anthony Baltodano, founder of Mission Inbox and a decade-long deliverability expert, to unpack the exact tech and tactics that keep your emails landing where they belong.What you’ll learn:Email Deliverability 101 – why SPF, DKIM & DMARC are the “carrier, wax-seal & security guard” of emailHow to warm up domains (and why skipping it tanks reputation)Plain-text vs HTML: balancing design with inbox placementThe hidden risks of cheap domain registrars (and why you should move DNS to Cloudflare)Tools Tony recommends for beginners (Beehiiv + MailReach) & for scale (Mission Inbox)Weekly health checks: simple placement tests that take 10 minutesReal-world horror stories: platform outages, blacklists, and how to dodge themTimestamps00:00 – Intro & why deliverability matters02:33 – Tony’s background: SDR → deliverability consultant → Mission Inbox05:35 – What actually happens after you hit “send”06:56 – SPF, DKIM, DMARC explained with a “letter & seal” analogy11:32 – Copy, links & images: how content triggers spam filters15:54 – Why Apple & Yahoo open emails before users do18:45 – Domain warm-up: what it is and best tools (WarmE.io, MailReach)23:10 – Domain reputation factors: registrar, age, blacklists30:38 – Affordable starter stack: Beehiiv + placement testing35:30 – Tony’s 3-step deliverability checklist for creators👉 Subscribe to LetterStack for more operator-level interviews on scaling, monetizing, and protecting your newsletter business at letterstack.co.🔔 Hit the bell so you never miss an episode! Check out MissionInbox.com to explore Tony’s deliverability infrastructure platform.