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Emailens/MCP
Open Source

Email QA inside
your AI assistant.

9 tools for analyzing, fixing, and previewing HTML emails — runs locally, no account needed. Add screenshots and sharing with an optional API key.

Get StartedView on GitHub
npx -y @emailens/mcp

How it works

Three steps to inbox confidence

01

Install

One command adds Emailens to Claude Desktop, Claude Code, Cursor, or any MCP client.

02

Ask

Ask your AI to analyze an email, fix issues, or check deliverability. It picks the right tools automatically.

03

Ship

Get compatibility scores, fix prompts, diff reports, and screenshots — all in your editor.

Local tools

7 tools, no account needed

All analysis runs locally via the open-source engine. No API calls, no signup, no rate limits.

preview_email

Full preview with transforms, scores, dark mode, inbox preview, and size check across 15 clients

Free
analyze_email

Quick CSS compatibility analysis with per-client scores and warnings

Free
audit_email

Comprehensive audit — spam, links, accessibility, images, inbox preview, size, templates

Free
fix_email

Structured fix prompt with CSS and structural changes the AI can apply directly

Free
diff_emails

Compare two HTML versions — see score changes, fixed issues, and regressions per client

Free
check_deliverability

SPF, DKIM, DMARC, MX, and BIMI checks with a deliverability score

Free
list_clients

Reference list of all 15 supported email clients with engines and dark mode support

Free

With API key

Add screenshots and sharing

Set EMAILENS_API_KEY to unlock hosted features. Free plan includes 30 previews/day.

capture_screenshots

Real browser screenshots across 15 clients with light and dark mode. Hosted on CDN.

API Key Required
share_preview

Shareable links — recipients see full analysis without an account. Dev plan required.

API Key Required

Free plan: 30 previews/day. Get your API key

Examples

What you can ask

“Analyze this email HTML and tell me what breaks in Gmail and Outlook”
“Fix the flexbox and border-radius issues for all clients”
“Compare the original and fixed versions — did the scores improve?”
“Check if company.com has SPF and DMARC set up correctly”
“Take screenshots of this email across all clients”

Setup

Get started in 30 seconds

Claude Code

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

Claude Desktop

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

With API Key (local + screenshots & sharing)

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

Remote (no install, API key required)

{
  "mcpServers": {
    "emailens": {
      "url": "https://emailens.dev/api/mcp",
      "headers": {
        "Authorization": "Bearer ek_live_..."
      }
    }
  }
}

No npm or Node.js required. All analysis runs server-side. Get your free API key

Coverage

15 email clients

Gmail
Gmail Android
Gmail iOS
Outlook 365
Outlook (New)
Outlook Classic
Outlook iOS
Outlook Android
Apple Mail
Apple Mail iOS
Yahoo Mail
Samsung Mail
Thunderbird
HEY Mail
Superhuman

Outlook Classic deprecated Oct 2026. Outlook iOS and Android added in v0.4.0.

Ready to try it?

One command. No signup required.

claude mcp add emailens -- npx -y @emailens/mcp
Full setup guide