Email client support table and compatibility checker

This tool helps email developers check feature support before campaigns ship.

What this compatibility table is useful for

• Preflight checks for HTML email templates
• Identifying risky CSS before production sends
• Comparing feature support across clients as a caniemail-style alternative

Typical workflow

1. Paste the raw HTML from your email template
2. Review feature support percentages
3. Replace unsupported markup with safer fallbacks
4. Re-test and then send QA emails

CI release gate pattern

1. Trigger a compatibility check for every release-candidate template.
2. Keep a baseline threshold for critical client support percentages.
3. Store failed-feature output with build artifacts for triage.
4. Block deploy when required client cohorts fail.

Pair this with:

• Email client testing workflow
• Email deliverability test
• Email Sandbox API

Suggested pass thresholds

• Critical transactional templates: no 'NOT_SUPPORTED' features in required client cohort.
• Campaign templates: allow partial support only for non-blocking design elements.
• Auth and account templates: enforce strict CTA and layout compatibility gates.

Reporting and ownership

• Assign each template family to a release owner.
• Route failures to engineering or QA with reproducible HTML input.
• Track weekly trend lines for unsupported features to prevent regression drift.