Email marketing for ecommerce: deliverability, cadence, and the silent killers

Why email still wins

Email has been pronounced dead for about 15 years. In the same 15 years, it has remained the highest-ROI channel for most ecommerce stores, on average producing $30-40 in revenue for every $1 spent. It outperforms Meta, Google, TikTok, organic social, and every other comparable channel on ROAS.

Not because email is clever. Because:

• You own the list. If Meta bans your account or TikTok changes its algorithm, your list is still yours
• Email arrives in a focused inbox. Unlike social, where your content competes with all other content
• Email converts warm audiences. Someone who gave you their email is already higher-intent than a cold social impression
• Email costs pennies to send. The cost is in the tooling and the work, not the per-send cost

This post is about using email well: list building, deliverability, content, cadence, and the specific mistakes that kill programmes. It pairs with the retention post, which covered the five-email automation programme. This post covers the channel at a broader level.

Building the list from zero

An email list isn't a vanity metric; it's the compounding asset your store gets to keep. Build it deliberately.

List sources that work:

• Popup on site with a genuine incentive (10% off, early access, a guide specific to your category). Fires after 15-30 seconds or on exit intent
• Inline signup in blog posts and product pages. Not a popup; a contextual signup form
• Order flow signup (pre-checked opt-in where legal, otherwise an obvious opt-in). The single biggest-volume source for most stores
• Content offers (size guide, style lookbook, buyer's guide) gated by email. Works well for considered purchases
• Giveaways / contests if done carefully. Attract bargain-hunters but also real customers; follow up fast
• Social bio links pointing to a signup page with a specific offer

List sources that waste your time:

• Buying email lists (illegal in most places; kills deliverability even where legal)
• Scraping emails from LinkedIn / anywhere
• "Subscribe for updates!" without a specific reason to subscribe

Quality matters more than volume. 5,000 engaged subscribers beat 50,000 who ignore every send.

Deliverability: the silent killer

You can have the best emails in the world. If they go to spam, they don't exist. Most ecommerce email programmes degrade silently because they never address deliverability. Your open rate drops from 28% to 18% over 6 months, and you think "emails are just getting worse", but actually Gmail moved you to spam.

The fundamentals:

• SPF, DKIM, DMARC records on your sending domain. If you don't know what these are, ask your email platform. All three should be configured before you send a single email
• A consistent sender domain. Use hello@yourbrand.com, not hello@ESP-subdomain.com. Branded domain signals legitimacy
• Warm-up new domains / IPs gradually. Sending 10,000 emails on day 1 from a brand-new domain is spam pattern; email providers notice
• Monitor bounce rate. Clean the list regularly. A 5%+ bounce rate tanks deliverability
• Segment engaged vs. unengaged. Don't send the same volume to everyone; focus high-frequency sends on people who open

Warning signs you have a deliverability problem:

• Open rates drop 20%+ over 2-3 months with no content change
• Click rates halve
• Gmail test account (always keep one) starts routing your mail to Promotions or Spam
• Your platform's deliverability score drops

Fix deliverability before anything else. Perfect creative to the spam folder is perfect waste.

Newsletter vs broadcast vs automation

Your email programme has three distinct flavours; most stores don't differentiate them clearly:

Newsletter / broadcast (scheduled):

• "Here's what's new this month"
• New product launches, restocks, sales, content
• Sent to a segment (often all active subscribers)
• Cadence: 1-4 per month for most stores

Automation (triggered):

• Welcome series, abandoned cart, post-purchase, winback
• Triggered by customer behaviour
• Runs 24/7 once built
• The highest-ROI email type for ecommerce
• Covered in the retention post

Transactional:

• Order confirmation, shipping notification, delivery notification, password reset
• Triggered by specific actions
• Highest-open category of any email (60-80%)
• Worth optimising because they're read

Most stores over-invest in broadcasts and under-invest in automation and transactional. The ROI is backwards from the time spent.

What to actually email

The cliché: "provide value, don't just sell". The reality is subtler. Your subscribers opted in because they care about your product. They don't want to read your founder's philosophy every week. But they also don't want another coupon email.

Content that works for ecommerce newsletters:

• Restocks of popular items with enough detail to buy immediately
• New product launches with the story behind the product (not your brand story; this product's story)
• Genuinely useful content: size guide for new collection, how-to-wear, care instructions
• Seasonal relevance: "here's what we're making for summer" with products below
• Customer stories / reviews with the product they bought
• Behind-the-scenes for brand connection, sparingly (once a month max)

Content that doesn't work:

• Sale emails every week (trains customers to wait for the sale)
• Corporate updates nobody cares about ("we moved offices!")
• Re-hashed Instagram posts
• Newsletter with no specific action to take

Rule of thumb: every email should have one clear ask. Buy this product. Read this article. Redeem this code. Without a specific action, the email is a press release.

Cadence: how often to send

The answer is "more than most stores think, less than big brands". The right cadence depends on your list and your content.

Guidelines:

• Starting out (under 1,000 subscribers): weekly is fine if you have content; fortnightly if you don't
• Mid-size (1k-50k subscribers): 1-3 broadcasts per week is the sweet spot for most categories
• Fashion / FMCG / seasonal categories: 2-4 per week during peak seasons
• Considered-purchase categories (furniture, jewellery, technical): 1-2 per week maximum
• B2B / professional: 1-2 per week, tighter segmentation

Unsubscribe rate is your feedback. If it jumps when you increase frequency, ease back. If it stays flat at higher frequency, the emails are still delivering value.

Segmentation that actually helps

"Send the right email to the right person" is the cliché. Actual segments that matter for ecommerce:

1. Active customers (last 90 days): highest ROI. Send more to these
2. Dormant customers (90-365 days): winback campaigns; exclude from normal broadcasts if deliverability is a concern
3. One-time vs repeat: one-time buyers need more trust-building; repeat buyers need new-product notifications
4. Category buyers: people who bought in category X get emails about category X
5. VIPs (top 10% by revenue): different tone, occasionally exclusive access, higher cadence OK
6. Non-buyers: subscribers who've never purchased. Nurture them with content, not discount spam

Don't over-segment. Too many segments means too much content to produce and most send to underpowered segments. Five segments is plenty for 90% of stores.

Subject lines: where most of the variance lives

Every other element of an email is wasted if the subject line doesn't open.

What works:

• Specific numbers: "15% off through Friday" beats "limited time sale"
• Curiosity + value: "The one thing we changed about our hoodies" (genuinely interesting, not clickbait)
• Personal feel: "Sarah, your jeans are back in stock"
• Short: under 50 characters for mobile preview

What doesn't:

• ALL CAPS
• Emoji-heavy subject lines
• Vague ("Important update about your account")
• Spam triggers ("FREE!!!", "Guaranteed!", multiple exclamation marks)

Testing subject lines:

Same campaign, same content, two different subject lines. Send to 20% of list each; winner goes to the remaining 60%. If your platform doesn't do this natively, do it manually with two segments.

Variance between good and bad subject lines on the same campaign: 20-40% open rate difference. This is the single highest-leverage A/B test you can run in email.

Common email mistakes

Things that silently kill programmes:

1. Every email is a sale. Trains customers to wait for discounts; erodes full-price conversion
2. No unsubscribe link (or hidden one). Illegal in most jurisdictions; also hurts deliverability
3. Image-only emails. Spam filters flag these; if images load slowly, your email is empty
4. Sending the same email to everyone. Deliverability hits when unengaged subscribers don't open
5. No clear sender. "Acme Team" instead of "Anna at Acme" loses personal connection
6. Every month is a newsletter; no automations running. Leaving revenue on the table
7. Never reading reply emails. Customers reply to your emails with questions; treating those as noise misses the highest-value conversations
8. Treating email as a broadcast channel only. It's a conversation. Ask questions sometimes. Reply personally

What Shoprocket handles

• Built-in email marketing with editor
• Monthly send limits per tier: 10k / 25k / 50k / 100k marketing emails (transactional emails are unlimited)
• Customer Tags for segmentation
• Dynamic Customer Groups for segment-by-behaviour targeting
• Automated transactional emails out of the box (order confirmation, shipping, delivery)
• Abandoned cart recovery with configurable timing

<!-- EXAMPLE ONLY. Grab your real snippet from Sales channels → Embeds in your dashboard -->
<script src="https://cdn.shoprocket.io/loader.js" data-pk="pk_yourkey"></script>
<div data-shoprocket="catalog" data-embed-id="emb_xxx"></div>

For more advanced automation (multi-step journeys, behavioural triggers, SMS-plus-email orchestration), integrate with Klaviyo, Omnisend, or Postscript alongside Shoprocket. Those are purpose-built for ecommerce email and pay back at list sizes over 5,000-10,000 where the segmentation and automation save real time.

Tip: Once a quarter, unsubscribe yourself from your own list and sign back up. Walk through your welcome, first newsletter, abandoned cart (add something to cart and wait). Most programmes have degraded in some way since they were last reviewed. A 90-minute audit catches it.

TL;DR

• Email remains the highest-ROI channel for most ecommerce stores. Not dead
• Build the list quality-first. 5k engaged beats 50k dormant
• Deliverability is the silent killer. SPF/DKIM/DMARC + sender domain + bounce hygiene are non-negotiable
• Three email types: newsletter, automation, transactional. Automation has the highest ROI; most stores over-invest in newsletters
• Content beyond "buy now": restocks, launches with context, seasonal relevance, customer stories
• Cadence: 1-3 per week for most mid-sized stores; track unsubscribe rate as feedback
• Segment the five segments that matter; don't over-segment
• Subject line tests have 20-40% variance. Highest-leverage A/B test in email
• Avoid the programme-killers: discount-every-email, image-only, ignoring replies, image-only

Start a free trial and get transactional emails + built-in email marketing with strong deliverability built in from day one. 14 days, no card.