# emailens/mcp [Health: Active]

**Category:** 💬 Communication  
**Repository:** https://github.com/emailens/mcp  
**GitHub Stars:** 7  
**npm Downloads (last month):** 1756  
**Views:** 5  
**Installs:** 0  
**Upvotes:** 0  
**Directory Page:** https://allmcps.com/mcp/emailens-mcp

## Description
Official MCP server for Emailens, the rendering linter for email. Lint HTML email for rendering issues across 15 clients (Gmail, Outlook, Apple Mail and more), score CSS compatibility 0-100 per client, simulate dark mode, and get framework-native fix snippets for React Email, MJML, and Maizzle. npx -y @emailens/mcp

## Tools
Capabilities this server exposes over MCP:

- **preview_email** — Full email compatibility preview, transforms HTML for 21 email clients (Gmail, Outlook, Apple Mail, Yahoo, Samsung, Thunderbird, HEY, Proton Mail, AOL, Fastmail, Superhuman), analyzes CSS, generates scores, simulates dark mode, checks inbox preview and email size.
- **analyze_email** — Quick CSS compatibility analysis, returns per-client scores and one finding per problem, listing the clients it affects. For HTML input each finding carries loc (line, column, offset) and alsoAtLines, so you can edit the exact source. Narrow with clients, or pass detail:'full' for the per-client breakdown with fix snippets. Use audit_email for a full quality report (spam, links, a11y, images, etc.).
- **audit_email** — Comprehensive email quality audit: CSS compatibility, spam scoring, link validation, accessibility, images, inbox preview, size (Gmail clipping), template variables, content overflow, visual fallbacks, dark-mode and mobile text contrast, design consistency, structural faults in Outlook-only VML (which lives inside conditional comments and is invisible to every other check), and style survival: CSS a client parses correctly and then discards, such as a stylesheet past Gmail's 16 KB ceiling or every rule after a `}}`, which no support matrix can express. For HTML input, findings tied to a specific element carry loc (line, column, offset) so you can edit the exact source. Compatibility is collapsed to one finding per problem listing the clients it affects; pass detail:'full' for the per-client breakdown with fix snippets. Use skip to omit checks and clients to narrow which clients are reported.
- **fix_email** — Generate a structured fix prompt for email compatibility issues. Returns markdown with the original code, detected issues (CSS or structural), fix snippets, and format-specific instructions. Use after preview_email or analyze_email.
- **list_clients** — List every supported email client with IDs, names, engines, and dark mode support.
- **diff_emails** — Compare two email HTML versions, shows score changes, fixed issues, and newly introduced issues per client. Use after making fixes to verify improvements.
- **check_deliverability** — Check email deliverability for a domain: SPF, DKIM, DMARC, MX, and BIMI records. Returns a score (0-100) and actionable issues. Uses DNS lookups (no API key needed).
- **capture_screenshots** — Capture real email screenshots across 21 clients (Gmail, Outlook, Apple Mail, etc.) with light and dark mode variants. Screenshots are rendered in real browsers and hosted on CDN. Requires EMAILENS_API_KEY env var — free plan at emailens.dev?ref=mcp.
- **share_preview** — Create a shareable link for an email preview. Recipients see the full analysis without needing an account. Requires EMAILENS_API_KEY env var and Dev plan ($9/mo).

## Claude Desktop Quick Installation
Install path detected from listing signals. Uses `npx` (confidence: high):

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

## Documentation

## What emailens/mcp does

emailens/mcp analyzes email templates against 21 supported email clients, including Gmail, Outlook, Apple Mail, Yahoo, Samsung, Thunderbird, HEY, Proton Mail, AOL, Fastmail, and Superhuman. It can inspect raw HTML or compile MJML, Maizzle, and React Email input before analysis, so checks apply to the HTML recipients receive.

The toolset covers both focused compatibility work and broader quality review. CSS findings include affected clients, compatibility scores, severity, and source locations for HTML input. Audits extend into spam signals, links, accessibility, images, Gmail size clipping, template variables, overflow, dark-mode and mobile contrast, visual fallbacks, design consistency, and Outlook VML structure. A separate deliverability check inspects SPF, DKIM, DMARC, MX, and BIMI records through DNS lookups.

## How it works

Run the package locally with MCP over stdio, or connect to the hosted MCP endpoint. Local analysis tools do not require an account. The server accepts either a template string or an absolute source-file path; file extensions can select the input format. Client filters let a request focus on selected client IDs, while audit requests can skip individual checks and choose a targeting policy.

`analyze_email` provides a quicker CSS-focused result than `audit_email`. Its default response groups each problem into one finding and lists the clients affected. Full detail adds per-client information and fix snippets. HTML findings include line, column, offset, and length data for the first occurrence, plus line numbers for additional occurrences. Compiled formats omit these positions because analysis occurs after compilation.

## Setup and configuration

Install and launch the local server with:

```bash
npx -y @emailens/mcp
```

A Claude Desktop configuration can start it through the `command` and `args` fields:

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

Claude Code can register the same command with `claude mcp add emailens -- npx -y @emailens/mcp`. An optional `EMAILENS_API_KEY` enables screenshot capture and preview sharing for the local setup. The hosted endpoint at `https://app.emailens.dev/api/mcp` requires a bearer API key and does not require npm or Node.js on the client machine.

## Tools and capabilities

- `preview_email` transforms and previews an email across supported clients, analyzes CSS, scores compatibility, simulates dark mode, and checks inbox preview and size.
- `analyze_email` returns focused CSS findings, client scores, source locations, and optional detailed fixes.
- `audit_email` runs the broader quality, compatibility, accessibility, deliverability-related content, and visual checks.
- `fix_email` produces a structured Markdown repair prompt with detected issues, snippets, and format-specific instructions.
- `list_clients` returns client IDs, names, rendering engines, and dark-mode support.
- `diff_emails` compares two versions and reports score changes, resolved issues, and regressions by client.
- `check_deliverability` checks domain DNS records and returns a score with actionable issues.
- `capture_screenshots` renders light and dark variants in real browsers and hosts the resulting screenshots on a CDN; it requires `EMAILENS_API_KEY`.
- `share_preview` creates a preview link that recipients can open without an account; it requires the API key and a Dev plan.

## Limitations and notes

Source locations are available for HTML input, not generated output from JSX, MJML, or Maizzle. Narrowing the client list changes the reported scope but not the whole-email scores. Audit results distinguish errors and warnings from informational findings; informational compatibility fallbacks are not necessarily problems to remove. Screenshot capture and sharing are the API-backed features, while local analysis works without an account.

_Full upstream README: https://allmcps.com/mcp/emailens-mcp/readme_