@emailens/mcp

MCP server for email compatibility analysis. Analyze, preview, diff, and fix HTML emails across 15 email clients — plus capture real screenshots and create shareable links with an optional API key.

Built on @emailens/engine.

Install

npx -y @emailens/mcp

Setup

Claude Desktop

Add to claude_desktop_config.json:

{
  "mcpServers": {
    "emailens": {
      "command": "npx",
      "args": ["-y", "@emailens/mcp"]
    }
  }
}

Claude Code

claude mcp add emailens -- npx -y @emailens/mcp

With API Key (optional — unlocks screenshots + sharing)

{
  "mcpServers": {
    "emailens": {
      "command": "npx",
      "args": ["-y", "@emailens/mcp"],
      "env": {
        "EMAILENS_API_KEY": "ek_live_..."
      }
    }
  }
}

Get your free API key at emailens.dev/settings/api-keys.

Tools

Local Tools (no account needed)

preview_email

Full email compatibility preview — transforms HTML for 15 clients, analyzes CSS, generates scores, simulates dark mode, checks inbox preview and email size.

analyze_email

Quick CSS compatibility analysis — returns per-client scores and warnings. Faster than audit_email when you only need CSS compatibility.

audit_email

Comprehensive quality audit — CSS compatibility, spam scoring, link validation, accessibility, images, inbox preview, size (Gmail clipping), and template variables.

fix_email

Generate a structured fix prompt for compatibility issues. Returns markdown with fix instructions that the AI can apply directly.

list_clients

List all 15 supported email clients with IDs, names, engines, and dark mode support.

diff_emails

Compare two email HTML versions — shows score changes, fixed issues, and introduced issues per client.

check_deliverability

Check email deliverability for a domain — SPF, DKIM, DMARC, MX, BIMI records with a score and actionable issues.

Hosted Tools (require EMAILENS_API_KEY)

capture_screenshots

Capture real email screenshots across 15 clients in real browsers. Screenshots are hosted on CDN.

Free plan: 30 previews/day. Sign up

share_preview

Create a shareable link. Recipients see the full analysis without an account.

Requires Dev plan ($9/mo). Share links expire after 7 days (Dev) or never (Pro).

Supported Email Clients (15)

Development

bun install
bun run build
bun test
bun run typecheck