If your e-commerce brand sends marketing emails, transactional receipts, or automated flows, this guide covers everything that determines whether those emails actually reach a customer’s inbox. Email deliverability isn’t one setting or one fix. It’s a combination of technical authentication, sender reputation, and compliance with rules that shift more often than most store owners realize.

This guide gives you the full picture. Where a topic goes deep enough to deserve its own dedicated breakdown, we’ve linked to it.

What Email Deliverability Actually Means

Deliverability is whether an email you send actually lands in the inbox, as opposed to spam, or getting silently blocked before it ever arrives. It’s separate from open rates and click rates — those measure what happens after an email is delivered. Deliverability measures whether it was delivered at all, and it’s invisible until something breaks.

Most store owners first notice a deliverability problem the same way: open rates quietly drop, with no change in subject lines, send times, or offer. We cover the full list of warning signs your emails aren’t landing in detail separately — it’s worth checking against your own recent numbers.

The Three Records That Authenticate Every Email

Every email sent from your domain is checked against three DNS-based technical records. Together, they tell Gmail, Yahoo, and Outlook whether the email is genuinely from you.

SPF (Sender Policy Framework)

SPF lists which mail servers are allowed to send email on your domain’s behalf. A domain can only have one valid SPF record — a second one, or a broken one, causes failures that are often misdiagnosed as something else entirely. We cover a full breakdown of SPF records [link once published] including the most common configuration mistake we see.

DKIM (DomainKeys Identified Mail)

DKIM attaches a cryptographic signature to outgoing email, proving it wasn’t altered in transit. It’s tied to whichever platform sends the mail (Klaviyo, Google Workspace, your storefront’s transactional emails), and each one needs its own correctly published DKIM record. We go deeper on how DKIM signing actually works [link once published] and the alignment issues that most often break it.

DMARC (Domain-based Message Authentication)

DMARC tells receiving mail servers what to do when SPF or DKIM fails, and reports back on suspicious activity. It has three policy levels — none, quarantine, and reject — and moving through them too quickly is one of the most common ways a store accidentally blocks its own legitimate email. We explain the three DMARC policy levels explained [link once published] and the staged rollout that avoids that mistake.

Sender Reputation and Blacklists

Authentication alone doesn’t guarantee delivery. Mailbox providers also track sender reputation — bounce rates, spam complaint rates, and engagement — separately from whether SPF/DKIM/DMARC pass. A domain or sending IP can end up on a blacklist even with perfect authentication, usually after a sudden change in sending volume or a spike in complaints.

If deliverability drops suddenly and authentication checks out fine, a blacklist check is usually the next step. We cover how to check if your domain is blacklisted [link once published] and, just as importantly, why you shouldn’t try to fix a blacklist listing yourself without understanding what caused it.

Google and Yahoo’s Bulk Sender Rules

In 2024, Google and Yahoo introduced stricter requirements for anyone sending bulk or marketing email, including authentication enforcement, spam-rate thresholds, and mandatory one-click unsubscribe.  [VERIFIED]  — Google’s official Email sender guidelines; Yahoo’s Senders Hub. Stores that haven’t reviewed their setup since these changes are frequently the ones seeing the steepest, most confusing deliverability drops. We break down Google and Yahoo’s current bulk sender rules [link once published] and what compliance actually requires.

Platform-Specific Considerations

General deliverability principles apply everywhere, but specific platforms introduce their own quirks. Klaviyo users in particular run into deliverability issues tied to how the platform handles sending domains and DMARC alignment — covered in why Klaviyo flows specifically get filtered [link once published].

Deliverability is also one of the most overlooked risks during a platform migration. Moving from one email platform (or one storefront platform) to another can quietly reset sender reputation or break existing authentication records if it isn’t planned for. We cover this in protecting deliverability during a platform migration [link once published].

Why This Isn’t a DIY Fix

Every mechanism in this guide is described in enough detail to understand what’s happening and why it matters. None of it is a step-by-step configuration walkthrough, and that’s deliberate. A domain can only have one valid SPF record. A DMARC policy set too aggressively can silently block your own legitimate mail. Getting any of this wrong is often worse than the original problem, and it’s rarely obvious that something went wrong until weeks later when revenue has already been affected.

A proper deliverability fix starts with a full diagnosis of what’s currently published, what’s broken versus merely suboptimal, and a staged rollout that protects your existing mail flow while strengthening it.

What an Alneeko Email Deliverability Audit Covers

• A full technical check of your domain’s SPF, DKIM, and DMARC status
• Blacklist and sender reputation review
• A plain-language report explaining exactly what’s wrong and why, no jargon
• A prioritized, staged fix plan that protects your existing email delivery while we correct it
• Compliance check against current Google and Yahoo bulk sender requirements

Get Your Domain Checked

If any part of this guide sounded familiar — a recent drop in open rates, a platform switch, or simply never having checked this before — it’s worth a proper look before it costs another quarter of lost revenue. Book an Email Deliverability Audit with Alneeko Technologies and get a clear, written report on exactly where you stand.