Health checks

The editor watches your email for problems and surfaces them in two places: small health badges in the preview toolbar (at-a-glance) and a comprehensive Issues drawer (the full list). Click any badge to open the drawer.

The badges

Four chips sit at the right of the preview toolbar, always visible:

Chip	What it shows
Words / size	Total word count and HTML size in KB. Informational.
Errors ⚠	Green dot = clean. Red count = MJML parse errors.
Images 🖼	Green count = all images load and have alt text. Gold = some images are missing alt text. Red overlay = some images don't load at all.
Links 🔗	Green count = all hrefs resolve. Red overlay = broken or placeholder links.

Hover any chip for a quick tooltip. Click any chip to open the full Issues drawer.

The Issues drawer

A right-side drawer that groups every issue by severity:

• Errors (red) — must be fixed before sending. Examples: MJML parse error, image fails to load, broken link.
• Warnings (gold) — should review but not blocking. Examples: image missing alt text.
• Info (blue) — purely advisory.

Each row shows:

• A coloured severity dot.
• The issue title (e.g. "mj-image is missing alt text").
• A one-line explanation of who's affected (e.g. "Recipients using screen readers can't perceive this image").
• The category and (if applicable) line number.
• A Jump button that scrolls the editor to that element and closes the drawer.

Open the drawer any time via a badge click. The drawer auto-refreshes as you edit — fix an issue and it disappears from the list immediately.

What's checked today

Structural (Phase 0)

Check	Severity	Category
MJML structural parse errors	Error	mjml
Image fails to load (<img> or background)	Error	images
Broken or placeholder link (href="#", malformed URL)	Error	links
Image missing alt text	Warning	accessibility

Subject — emails only

Check	Severity
Subject is empty	Error
Subject is < 30 characters	Warning
Subject is > 60 characters	Warning
Subject is mostly UPPERCASE	Warning
Subject has excess punctuation (!!, ??, 3+ !)	Warning
Subject contains a spam-trigger phrase ("act now", "free money", "click here", …)	Warning

Deliverability & compliance — emails only

Check	Severity
Body text contains spam-trigger phrases	Warning
No unsubscribe link or {{unsubscribeLink}} merge tag	Error
No postal address detected in footer	Warning

The unsubscribe check is an error, not a warning: the 2024 Gmail/Yahoo sender rules and CAN-SPAM both require a working unsubscribe option. The footer-address check is a warning because many templates resolve the address from a merge tag, which we can't verify at compose time.

Pre-flight on Send

When you click Send on an email, the Send Wizard's Review step automatically runs the full health check. What happens depends on what was found:

• Errors (red) — the Send button is disabled. Fix the issues, then come back. You can still save the email as a draft; the gating is on actual sending, not on saving.
• Warnings (gold) — the Send button stays enabled. Clicking it shows a confirmation modal listing the warnings, with two choices: Send anyway or Review issues (jumps to the Issues drawer).
• All clear (green) — a "All pre-flight checks passed" confirmation appears in the Review step. Send normally.

This way the editor catches problems before they ship rather than after a recipient sees a broken email.

Image quality

Two extra checks now run on every image alongside the broken/alt checks:

• Missing dimensions — if the rendered <img> has neither a width nor a height attribute, you get a warning. Outlook desktop is particularly bad at handling these: it renders the image at full intrinsic size and shifts everything around it. We only flag when both are missing — MJML adds a width by default, so the warning only fires for truly under-specified images.

• Oversized (> 1 MB) — the editor fires a HEAD request for each image's URL to get its size, and warns when it exceeds 1 MB. Recipients on mobile data thank you for keeping images under 300 KB. Compression and resize tools live in the image editor. When the CDN doesn't allow HEAD or omits content-length, the check silently skips — we don't false-warn on images we can't actually measure.

When an image is broken (URL fails to load), only the broken-image error appears — the alt / dimensions / size checks are suppressed for that image until you fix the URL.

One-click AI fixes

Some warnings have an obvious AI-driven remedy. The Issues drawer shows a Fix button next to those:

• Missing alt text — click Fix and the AI looks at the image, generates a description, and applies it to the image's alt attribute. The image is briefly selected so you can see the change, and the issue disappears from the drawer on the next validation pass.

If the AI's output is off, you can always click the image and edit the alt text manually — the AI fix is a starting point, not a final answer.

Coming soon:

• Rewrite a too-long or spam-tripping subject within the 30–60 char window
• Insert a CAN-SPAM-compliant footer (unsubscribe + postal address) using your project branding

What's coming

• Image-to-text ratio — > 60% image area is a strong spam signal
• Image format — JPEG > 500 KB or PNG photographs (suggest WebP)
• Performance — HTML > 102 KB (Gmail clips your email)

Spam-trigger word list

The trigger phrases are curated for low false-positive rate. Examples: "act now", "buy now", "click here", "free money", "limited time", "no obligation", "winner", "guaranteed", "weight loss", "make money fast". The full list is at editor/lib/health/data/spam-words.json and versioned — corrections are welcome.

If your legitimate copy happens to use one of these phrases (e.g. an actual "limited time" promotion), the warning is intentional — consider rephrasing or accepting the slight inbox-placement risk. You can ignore individual warnings.

Power-user shortcut

Want to see every issue without hunting for a chip? Click any of the three issue-bearing chips (Errors / Images / Links). They all open the same drawer. The drawer shows everything regardless of which chip you clicked.

Why this matters

Most email-builder QA happens in the recipient's inbox — by then it's too late. The Issues drawer surfaces problems while you're editing, with one-click navigation to the source element. Combined with the upcoming pre-flight check on Send, it turns "did I remember to add alt text?" into "the editor told me before I clicked Send."