Email Design and Send Checklist

Pin one primary KPI before drafting — open rate, CTR, MQLs created, or revenue attributed. Campaigns optimized against three KPIs at once usually optimize against none. The marketing manager owns this call.

Build the segment in HubSpot, Marketo, Klaviyo, or whichever MAP you use, and save it with a versioned name (e.g., 2025Q1_NewsletterEU_v2). Suppress unsubscribes, hard bounces, and the 30-day suppression list. Ad-hoc segments built at send time are the most common cause of list-health regressions.

Check the segment's last-90-day bounce rate (target under 2%), complaint rate (under 0.1%), and inactive share. A list quiet for six months should run a re-engagement before a broad push, or the sender reputation hit will outlast the campaign.

600px content width, single-column body, fluid hybrid for mobile. Outlook on Windows still ships the Word rendering engine — avoid CSS grid, modern flex, and background images that depend on it. Use bulletproof button code (VML fallback) for the primary CTA.

Pull the latest assets from Frontify, Brandfolder, or your DAM rather than reusing last campaign's HTML — logo lockups change more often than templates do. Verify HEX values match the current brand book.

Above-the-fold CTA, repeated mid-content, repeated at footer. Each CTA carries the same UTM source/medium/campaign so click data aggregates cleanly in GA4. Button minimum 44×44px for touch targets.

Subject line under 50 characters so it doesn't truncate on mobile. Preheader complements rather than repeats the subject — wasted preheader space is a common gotcha. No spam-trigger words (FREE!!!, ALL CAPS, excessive punctuation).

One main idea per email; supporting points as scannable bullets or short paragraphs. Conversational tone for B2C, direct and value-led for B2B. Any quantitative claim needs a substantiation source per FTC guidance — keep the source link in the brief, not the email body.

Every merge tag needs a fallback value — "Hi {{first_name|there}}" never "Hi {{first_name}}". Empty token sends are the single most embarrassing avoidable email mistake. Spot-check 5-10 random recipients in the preview tool.

Required: a valid physical postal address, accurate sender identification, and non-deceptive subject/from lines. PO boxes are acceptable if registered with USPS. Footer pulls from the MAP's company-settings record — verify it isn't the old office address.

Run the sending domain through EasyDMARC, MXToolbox, or GlockApps. DMARC at p=quarantine or p=reject; DKIM signed by the MAP's selector; SPF includes the MAP's sending IPs. Gmail and Yahoo bulk-sender requirements (since Feb 2024) are now enforced — misalignment routes mail to spam silently.

Click the link in a test send and verify the recipient lands on the suppression page without further authentication. Gmail/Yahoo bulk-sender rules require List-Unsubscribe-Post header for one-click; check the source. Suppression must propagate within 10 business days under CAN-SPAM.

Test against at minimum: Gmail (web + iOS + Android), Outlook 365 desktop Windows, Outlook web, Apple Mail iOS, Yahoo. Dark-mode versions for Apple Mail and Outlook — logos on transparent backgrounds frequently invert badly. Save the screenshot grid as the audit artifact.

Click every link in a test send. UTM source/medium/campaign matches the team's UTM convention doc — drift here makes GA4 reports incomparable across campaigns. Check destination URLs aren't dev/staging.

Test a single variable — subject line, preheader, send time, or CTA copy. Hold variant size at 10-20% per arm so the winner deploys to the majority. Decide the success metric (open rate vs. CTR vs. conversion) before sending so the call isn't post-hoc.

Schedule rather than send-now so the segment, send time, and final asset are all locked in writing. Time-zone-aware sending where supported (HubSpot, Marketo) raises open rates for global lists. Avoid Friday afternoons and Monday 9am UTC unless the data says otherwise for your audience.

Watch the bounce rate, complaint rate, and inbox-placement signal in the MAP for the first 60 minutes. Spike in bounces above 3% means pause and investigate before the rest of the queue ships. Soft-bounce spikes can indicate IP throttling at the recipient ISP.

After the test window closes (typically 4-24 hours depending on list size and KPI), confirm the winning variant against the pre-declared success metric and deploy to the remaining 80-90% of the segment. Document which variant won and why for the next campaign retro.