# emailens/mcp [Health: Active]

**Category:** 💬 Communication  
**Repository:** https://github.com/emailens/mcp  
**GitHub Stars:** 7  
**npm Downloads (last month):** 1113  
**Views:** 3  
**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, and structural faults in Outlook-only VML (which lives inside conditional comments and is invisible to every other check). 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"],
    "env": {
      "EMAILENS_API_KEY": ""
    }
  }
}
```

**Requires environment variables:** `EMAILENS_API_KEY` — the values above are empty placeholders; fill in real credentials before running (see the repository for what each one is for).

## Documentation

## What emailens/mcp MCP server does

emailens/mcp MCP server gives an MCP-compatible client tools for inspecting and improving email templates before sending them. It evaluates email HTML across 21 client profiles, including Gmail, Outlook, Apple Mail, Yahoo, Samsung, Thunderbird, Proton Mail, Fastmail, and others. Results include client-specific scores, compatibility findings, dark-mode analysis, inbox preview checks, and email-size checks.

The server accepts HTML directly and can also process JSX, MJML, and Maizzle. When a template format is supplied, it is compiled before analysis so the checks apply to the resulting email HTML. React Email is also listed as a supported input framework in the project description.

## How it works

The local tools run through the npm package and do not require an account for compatibility analysis, audits, fixes, client listing, diffs, or DNS-based deliverability checks. An agent can start with `analyze_email` for a focused CSS review, use `audit_email` for a broader quality report, and then call `fix_email` to obtain structured Markdown instructions and format-specific fix snippets.

For HTML input, findings can include line, column, offset, and length information for the first occurrence, along with line numbers for additional occurrences. JSX, MJML, and Maizzle inputs are compiled first, so source positions are omitted rather than pointing to generated output. Findings can be narrowed to selected clients, and some reports support a full-detail mode or skipped checks.

## Setup and configuration

Install the emailens/mcp MCP server with Node.js and npm:

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

For Claude Desktop, register a server named `emailens` with `npx` as the command and `-y @emailens/mcp` as its arguments. The project also documents a hosted MCP endpoint at `https://emailens.dev/api/mcp`; that option requires an authorization bearer token and does not require a local npm installation.

Set `EMAILENS_API_KEY` when using hosted capabilities from a local configuration. The project states that API-key access unlocks screenshot capture and sharing. The free plan provides 30 screenshot previews per day, while `share_preview` requires the Dev plan listed at $9 per month.

## Tools and capabilities

The emailens/mcp MCP server exposes these tools:

- `preview_email` transforms and evaluates an email across supported clients, including CSS scores, dark-mode simulation, inbox preview, and size checks.
- `analyze_email` returns grouped CSS compatibility findings and per-client scores, with optional client filtering and detailed output.
- `audit_email` checks compatibility, spam signals, links, accessibility, images, variables, overflow, contrast, design consistency, and Outlook VML structure.
- `fix_email` produces a structured fix prompt based on detected compatibility or structural problems.
- `list_clients` returns client IDs, names, rendering engines, and dark-mode support.
- `diff_emails` compares before-and-after versions and reports score changes, fixed issues, and new issues.
- `check_deliverability` looks up SPF, DKIM, DMARC, MX, and BIMI records for a domain.
- `capture_screenshots` renders light and dark variants in real browsers and hosts the resulting screenshots on a CDN.
- `share_preview` creates a link that lets recipients view the full analysis without an account.

## Limitations and notes

Screenshot capture and share links are hosted features that require `EMAILENS_API_KEY`; sharing additionally requires the stated Dev plan. DNS deliverability checks use lookups and do not require an API key. Client filtering changes which findings are reported but does not change whole-email scores. The repository describes compatibility data for 255 CSS and HTML features, but support varies by email client, so a passing result for one client does not imply equivalent behavior elsewhere.

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