skill-email-html-mjml
A Claude Code skill that generates responsive, cross-client HTML email templates by producing MJML (MJML 4.x) and compiling it to production-ready, minified HTML suitable for Outlook and Gmail, including Outlook-specific handling (VML/ghost tables), Gmail clipping prevention, and accessibility-oriented MJML structuring.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
No credential handling or network API is described; the main security risks would be user-supplied template content reaching compilation/rendering. The README emphasizes template guards for dynamic tags (mj-raw), but it does not document sanitization/escaping practices or logging behavior. TLS/auth scores are limited because there is no service/API in scope.
⚡ Reliability
Best When
You need reliable, maintainable cross-client HTML email without manually coding tables/VML and want the skill to enforce validation and email-client-specific rendering constraints.
Avoid When
You require a hosted service with guaranteed uptime, API-based template management, or strict compliance artifacts beyond what template generation can provide.
Use Cases
- • Generate responsive marketing/transactional email templates from a natural-language brief
- • Compile MJML to Outlook/Gmail-safe HTML for ESPs (SendGrid/SES/Postmark/etc.)
- • Troubleshoot or standardize email rendering issues across clients using a consistent MJML-to-HTML pipeline
- • Produce accessible templates with alt text and title/preview metadata
Not For
- • Directly sending emails via an API (it focuses on template generation/compilation)
- • Use as a generic website/CMS template renderer (HTML email constraints are the focus)
- • Runtime email rendering in a browser (output is for email clients)
Interface
Authentication
No external authentication/API integration described; it runs as a Claude Code skill and relies on local tooling (Node.js + MJML in the user project).
Pricing
No pricing information provided; skill listing/usage implies a Claude Code capability rather than a standalone paid API.
Agent Metadata
Known Gotchas
- ⚠ This is a skill for template generation/compilation, not a transactional email-sending API.
- ⚠ Correctness relies on MJML compilation flags (e.g., minify) and component hierarchy constraints (e.g., mj-section/cannot be nested as described).
- ⚠ Template-engine tags must be protected with mj-raw to avoid MJML parsing; missing this can break generated output.
- ⚠ Email-client quirks (Outlook/Gmail size and CSS/head handling) are addressed by specific compile-time/config choices—changing them may regress rendering.
Alternatives
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Scores are editorial opinions as of 2026-03-30.