Shopify Email Deliverability: Why Your Emails Land in Spam (and How to Fix It)

Why Email Deliverability Is the Hidden Revenue Problem

You can write the best email marketing copy, set up perfect automation flows, and build a large subscriber list — and still have your emails land in spam for 30% of recipients. That means 30% of your email revenue is invisible, never reaching the inbox.

Email deliverability is the foundation of email marketing. Without it, everything else is wasted. This guide covers the technical and strategic steps to maximise inbox placement for your Shopify store emails.

Understanding How Email Deliverability Works

Email providers (Gmail, Outlook, Yahoo) use a combination of signals to decide whether your email goes to inbox, promotions tab, or spam:

• Authentication signals — Does your domain have proper SPF, DKIM, and DMARC records? Without these, major providers are increasingly likely to reject or spam-filter your emails.
• Sender reputation — Your sending domain and IP address have a reputation score based on engagement history. High open rates and low spam complaints = good reputation.
• Content signals — Spam trigger words, all-image emails with no text, suspicious links, and misleading subject lines all negatively affect deliverability.
• List quality — Sending to invalid addresses, non-engagers, or purchased lists damages your reputation with every send.

Step 1: Technical Authentication (Most Important)

SPF (Sender Policy Framework)

SPF is a DNS record that lists which servers are authorised to send email on behalf of your domain. Without SPF, receiving servers can’t verify that your sending platform (Klaviyo, Omnisend, etc.) is genuinely sending on your behalf.

Your email platform (Klaviyo, Omnisend, Shopify Email) will provide an SPF record to add to your domain’s DNS settings. It looks something like: v=spf1 include:sendgrid.net ~all. Add it as a TXT record in your domain registrar’s DNS settings.

DKIM (DomainKeys Identified Mail)

DKIM adds a cryptographic signature to your emails that proves they haven’t been tampered with in transit. Your email platform provides a DKIM record (a long CNAME or TXT record) to add to your DNS. Gmail in particular gives significantly better inbox placement to DKIM-authenticated emails.

DMARC

DMARC tells receiving servers what to do when SPF or DKIM checks fail — quarantine the email, reject it, or deliver it anyway. Since February 2024, Google and Yahoo require DMARC for bulk senders. Start with a policy of p=none (monitor only), then graduate to p=quarantine once you’re confident your authentication is correct.

Verification: Use MXToolbox (mxtoolbox.com) to check your SPF, DKIM, and DMARC records are correctly configured.

Step 2: List Hygiene

Every email send to an unengaged subscriber slightly damages your sender reputation. Regular list hygiene keeps your deliverability healthy:

• Remove hard bounces immediately — Hard bounced addresses (invalid email addresses) should never be sent to again. Your email platform should handle this automatically.
• Suppress unengaged subscribers — Create a segment of subscribers who haven’t opened or clicked in 90 days. Run a re-engagement campaign. Remove those who still don’t engage.
• Never send to purchased lists — These lists are full of spam traps, invalid addresses, and people who’ve never heard of you. A single send to a purchased list can permanently damage your sending domain.
• Use double opt-in where possible — A confirmation email after sign-up ensures only valid, genuinely interested addresses enter your list.

Step 3: Sending Practices

• Warm up new sending domains — If you’ve just set up your email platform on a new domain, start with small sends (50–100 emails) and increase gradually over 2–4 weeks. Sudden high-volume sending from a new domain triggers spam filters.
• Consistent sending frequency — Irregular sending (nothing for months, then 5 emails in a week) hurts deliverability. Establish a consistent cadence.
• Segment before sending — Send campaigns to engaged segments first (opens in last 90 days). If engagement is good, expand to wider segments. Never blast your whole list for every campaign.
• Watch your spam complaint rate — Gmail Postmaster Tools shows your complaint rate. Keep it below 0.1%. Above 0.3% and you have a serious deliverability problem.

Step 4: Content Best Practices

• Use a healthy text-to-image ratio (at least 60% text, not all-image emails)
• Avoid spam trigger words: “free”, “guarantee”, “no risk”, “buy now” used excessively
• Include a plain-text version of every email
• Use your real domain in sender address (not Gmail or Hotmail)
• Include a physical address in the footer (legally required in UK and US)
• Make the unsubscribe link easy to find — recipients who can’t find it mark you as spam instead

Monitoring Your Deliverability

• Gmail Postmaster Tools — Free tool from Google showing your domain reputation and spam rate for Gmail recipients
• Mail-tester.com — Send a test email and get a deliverability score with specific issues flagged
• Your ESP’s deliverability reports — Klaviyo, Omnisend, and other platforms show open rates, bounce rates, and deliverability metrics per campaign

Good email deliverability is infrastructure, not marketing. Fix the technical foundations once and maintain the list hygiene practices ongoing. The reward is that every pound you spend on email marketing reaches its intended audience.