Email QA Checklist: Test Before You Send

The Email That Never Got Read. A promo email goes out to 40,000 subscribers. The subject line is sharp. The offer is strong.

The CTA button points to a product page that was removed three weeks ago.

Nobody caught it. Nobody looked. The email moved from draft to inbox with zero review steps in between.

That gap, between writing an email and sending it, is where most preventable failures live. Not in the copy. Not in the design. In the ten minutes nobody spent checking the thing before it went out to everyone.

Here is what to check before every send, and how to stop checking it by hand.

Why Email QA Gets Skipped

The final-step problem

Write, paste into ESP, send, no review step

Most email workflows end the moment the copy looks good. The writer finishes the draft, pastes it into the ESP, hits schedule. There is no checkpoint between "done writing" and "live in 40,000 inboxes."

QA is not built into the workflow. It has to be added on top, by someone, manually, every single time. Most teams skip that step because nothing forces them to take it.

QA treated as optional when deadlines are tight

When a send date is fixed and the copy comes in late, QA is the first thing cut. It feels safe to cut because it rarely causes visible damage at the moment.

The damage shows up after the send, when it is too late to fix.

Only 7% of marketing teams use automation specifically for QA testing. The other 93% rely on someone remembering to check, on a day when checking is the easiest thing to skip.

The cost of skipping it

Tone slips that read off-brand

A rushed edit changes a sentence. Nobody re-reads the whole email after that change. The tone shifts, the voice sounds off, and the subscriber notices before the marketing team does.

Rendering breaks in Outlook and Gmail

An email that looks perfect in the editor can fall apart in a real inbox. Fonts default to something else. Images do not load. Buttons stack wrong on mobile.

42.3% of recipients delete an email immediately if it fails to render on mobile. That is close to half the list gone before anyone reads a word.

Broken or redirected links

Product pages get taken down. URLs get restructured. Campaign links get reused from an old template without anyone checking where they actually point.

The CTA is the one link in the email that has to work. It is also the one most likely to go unchecked.

Missing alt text and accessibility gaps

Images without alt text fail for screen reader users and for anyone whose email client blocks images by default. Both groups see nothing where the message should be.

Accessibility gaps are invisible in the editor and obvious in the inbox.

The Four-Part QA Checklist

Brand voice check

Does the copy match your established tone

Every brand has a voice. Formal or casual, playful or clinical, first person or third. That voice is supposed to hold steady across every email, not just the ones with time to spare.

Check for:

• Word choices that clash with the brand vocabulary
• Sentence length drifting from the usual pattern
• A CTA that sounds more aggressive or more timid than usual
• Claims or promises that do not match past messaging

Manual review vs. automated scoring

A human reading for tone is slow and inconsistent. Two editors will flag different things on the same email. Neither has time to compare the draft against the last twenty sends.

An automated tone check runs the draft against a defined voice profile every time, in seconds, with the same standard applied to every email. It will not replace judgment on borderline cases, but it catches the obvious drift before a person even opens the file.

Rendering check

Desktop and mobile clients

The same email can look correct in one client and broken in another. Outlook renders CSS differently than Gmail. Apple Mail handles images differently than Yahoo. Mobile clients compress layouts in ways desktop previews do not show.

A rendering check means previewing the email across the actual clients your subscribers use, not just the one open on the screen while writing it.

Dark mode and light mode

Dark mode can invert colors, wash out logos, or turn a white background transparent in ways that break contrast entirely. An email that looks polished in light mode can be unreadable in dark mode on the same device.

Both modes need a pass before send. Neither can be assumed safe from the other.

Link check

Every URL returns a 200

Every link in the email, the CTA, the footer, the unsubscribe, the social icons, needs to resolve to a working page. A single broken link on the main CTA can sink the entire send.

This is a mechanical check. It does not require judgment, only consistency.

No slow or redirect-chained endpoints

A link that technically works but routes through three redirects adds load time and risk. Each redirect is a point where the chain can break later, even if it works at the time of the check.

Clean, direct links load faster and stay reliable longer.

Accessibility and grammar check

Alt text on every image

Every image needs alt text that describes its content or purpose. This covers screen reader users and anyone whose client blocks images by default, which is a significant share of any list.

An email with no alt text on its hero image often communicates nothing to a meaningful portion of recipients.

Grammar and spelling pass

A typo in the subject line or CTA undercuts credibility fast, especially at volume. This is the simplest check on the list and the easiest to automate completely.

How Migma Email Preflight Automates the Checklist

Brand Voice Guard

Scores tone against brand memory

Migma pulls brand context, tone, vocabulary, past emails, from a connected knowledge base and scores each new draft against it. The comparison runs automatically, before send, against the same standard every time.

Flags contextual mismatches

When a sentence drifts from the established voice, the tool flags it directly in the draft. This includes word choices that read too formal, too casual, or off from the brand's usual register.

Suggests on-brand phrasing

Flags come with suggested rewrites, not just warnings. The writer sees the mismatch and an on-brand alternative in the same place, without switching tools or guessing at a fix.

Compatibility Checker

Tests across 40+ email clients

The rendering check runs across more than 40 real email clients and devices, covering the major gaps between Outlook, Gmail, Apple Mail, and mobile inboxes.

Screenshots and compatibility score

Each client returns an actual screenshot, not a simulated preview, along with a compatibility score for the email as a whole. Broken layouts are visible before the send, not reported after it.

Client-specific fix suggestions

When a layout breaks in a specific client, the tool identifies which client and what broke, so the fix is targeted instead of a guess applied across the whole template.

Link Validator

Crawls every URL in the draft

Every link in the email, CTA, footer, unsubscribe, social icons, gets crawled automatically as part of the preflight pass.

Reports 200 vs. 404

Each URL comes back with a status. A working link shows a 200. A dead one shows a 404 or equivalent error, flagged directly against the link in question.

Flags slow endpoints and bad redirects

Beyond dead links, the validator flags slow-loading endpoints and redirect chains that add latency or risk. A link that resolves but takes several hops is marked the same as one that fails outright.

Quick Fix Suggestions

Inline edits for grammar and alt text

Grammar, spelling, and missing alt text are flagged inline, in the same editor the email was written in. No separate proofing pass required.

One-click accessibility fixes

Common accessibility gaps, missing alt text, contrast issues, come with a one-click fix rather than a manual edit for each instance.

Deliverability tips

The tool also surfaces deliverability signals, subject line risk, spam-trigger phrasing, send-time patterns, alongside the QA checks, so the email is evaluated on whether it will land, not just whether it looks right.

Where Preflight Fits Into a Real Workflow

One-click in the editor

For a single campaign, Preflight runs as one button inside the Migma editor. Write the email, click Preflight, get results across all four checks in the same window.

No exporting the draft. No switching to a separate QA tool. No copying links into a checker one at a time. The scores, screenshots, and flags appear next to the draft that produced them.

This is the fit for most sends: a marketer finishing a promo or newsletter who needs a final check before scheduling.

API automation in a release pipeline

For teams sending at higher volume, or generating emails programmatically, Preflight runs through the API instead of a manual click. A generation step calls the endpoint, gets a QA result back, and only proceeds to send if the email clears the checks.

This turns QA into a gate rather than a step someone has to remember. An email that fails link validation or renders broken in Outlook does not reach the send queue. It gets flagged and returned for a fix, the same way a failed test blocks a code deploy.

This is the fit for teams running transactional flows, high-frequency campaigns, or any pipeline where emails are generated faster than a human can review them one by one.

Integrations with Klaviyo and Shopify

Preflight is not limited to emails built and sent inside Migma. Emails exported to Klaviyo, or generated from Shopify product and order data, can run through the same checks before they go out on those platforms.

For Shopify, this matters most on emails built from live product data, order confirmations, abandoned cart, back-in-stock, where a broken link or missing image reflects directly on a specific product page. For Klaviyo, it means flows built or edited outside Migma still pass through the same brand voice, rendering, and link checks before a send.

Conclusion

QA gets skipped for the same reason every time: there is no step in the workflow that forces it. Writing an email and sending an email are treated as one motion, when they should be two, with a check in between.

That check does not need to take long. Brand voice, rendering across clients, working links, alt text and grammar, all four can run in a single automated pass instead of depending on someone remembering to look.

The cost of skipping QA is not evenly distributed. A tone slip is embarrassing. A broken CTA on a 40,000-subscriber send is a lost campaign, and sometimes a lost customer who never gets the message meant for them.

Enterprise teams already treat this as settled. More than 70% of large-scale campaigns run automated pre-send checks, not because it is best practice on paper, but because manual review does not hold up at volume.

The fix is not a new habit. It is a step that runs itself, every time, whether anyone remembers to ask for it or not.

Run Preflight on your next draft. Run your next email through Preflight before it goes out. Try Migma Email Preflight free.

Frequently Asked Questions