# emailens-mcp

> Use this tool when you need to analyze and optimize HTML emails for compatibility across multiple email clients, or to troubleshoot deliverability issues. It provides features such as email previews, CSS compatibility analysis, and deliverability checks, with inputs including HTML email source code and optional API keys, and outputs including compatibility scores, warnings, and shareable links. Use it when developing and testing email campaigns to ensure consistent rendering and high deliverability rates.

Canonical page: https://skillsregistry.net/skills/emailens-mcp-emailens-mcp  
JSON: https://api.skillsregistry.net/v1/skills/emailens-mcp-emailens-mcp

## Description

# @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`](https://github.com/emailens/engine).

## Install

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

## Setup

### Claude Desktop

Add to `claude_desktop_config.json`:

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

### Claude Code

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

### With API Key (optional — unlocks screenshots + sharing)

```json
{
  "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](https://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.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `html` | string | Yes | Email HTML source |
| `clients` | string[] | No | Filter to specific client IDs |
| `format` | enum | No | `"html"`, `"jsx"`, `"mjml"`, `"maizzle"` |

#### `analyze_email`

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

| Parameter | Type | Required | Description |
|---|---|---|---|
| `html` | string | Yes | Email HTML source |
| `format` | enum | No | Input format |

#### `audit_email`

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

| Parameter | Type | Required | Description |
|---|---|---|---|
| `html` | string | Yes | Email HTML source |
| `format` | enum | No | Input format |
| `skip` | string[] | No | Checks to skip (e.g. `["spam", "images"]`) |

#### `fix_email`

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

| Parameter | Type | Required | Description |
|---|---|---|---|
| `html` | string | Yes | Email HTML to fix |
| `format` | enum | No | Controls fix syntax |
| `scope` | enum | No | `"all"` or `"current"` |
| `selectedClientId` | string | No | Client ID for scoped fixes |

#### `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.

| Parameter | Type | Required | Description |
|---|---|---|---|
| `before` | string | Yes | Original email HTML |
| `after` | string | Yes | Modified email HTML |
| `format` | enum | No | Input format |

#### `check_deliverability`

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

| Parameter | Type | Required | Description |
|---|---|---|---|
| `domain` | string | Yes | Domain to check (e.g. `"company.com"`) |

### Hosted Tools (require `EMAILENS_API_KEY`)

#### `capture_screenshots`

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

| Parameter | Type | Required | Description |
|---|---|---|---|
| `html` | string | Yes | Email HTML source |
| `format` | enum | No | Input format |
| `clients` | string[] | No | Filter clients |
| `modes` | string[] | No | `["light"]`, `["dark"]`, or `["light", "dark"]` |
| `title` | string | No | Name for the preview |

Free plan: 30 previews/day. [Sign up](https://emailens.dev?ref=mcp)

#### `share_preview`

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

| Parameter | Type | Required | Description |
|---|---|---|---|
| `html` | string | Yes | Email HTML source |
| `title` | string | No | Display title |
| `format` | enum | No | Input format |

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

## Supported Email Clients (15)

| Client | ID | Dark Mode | Notes |
|---|---|---|---|
| Gmail | `gmail-web` | Yes | |
| Gmail Android | `gmail-android` | Yes | |
| Gmail iOS | `gmail-ios` | Yes | |
| Outlook 365 | `outlook-web` | Yes | |
| Outlook Windows | `outlook-windows` | No | |
| Outlook Windows Legacy | `outlook-windows-legacy` | No | Deprecated Oct 2026 |
| Outlook iOS | `outlook-ios` | Yes | New in v0.4.0 |
| Outlook Android | `outlook-android` | Yes | New in v0.4.0 |
| Apple Mail | `apple-mail-macos` | Yes | |
| Apple Mail iOS | `apple-mail-ios` | Yes | |
| Yahoo Mail | `yahoo-mail` | Yes | |
| Samsung Mail | `samsung-mail` | Yes | |
| Thunderbird | `thunderbird` | No | |
| HEY Mail | `hey-mail` | Yes | |
| Superhuman | `superhuman` | Yes | |

## Development

```bash
bun install
bun run build
bun test
bun run typecheck
```

## Trust

- **Trust score (0–1):** 0.50
- **Verification tier:** unverified

## Facts

- **Version:** 1.0.0
- **Skill type:** atomic
- **Execution layer:** mcp-remote
- **Runtime environment:** api
- **Category:** version-control
- **Updated:** 2026-05-11

## Source

- **Source listing:** [Smithery](https://smithery.ai/server/emailens-mcp/emailens-mcp)

## Use it

Resolve this record through the SkillsRegistry MCP server (no auth, read-only):

```
claude mcp add --transport http --scope user skillsregistry https://api.skillsregistry.net/mcp
```

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "get_skill",
    "arguments": {
      "slug": "emailens-mcp-emailens-mcp"
    }
  }
}
```

REST: `GET https://api.skillsregistry.net/v1/skills/emailens-mcp-emailens-mcp` · pull for local use: `GET https://api.skillsregistry.net/v1/skills/emailens-mcp-emailens-mcp/pull`

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