# @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 ```

MCP readiness

B · 88/100

Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here C+, 70.0/100), which weighs availability, conformance, p95 speed and descriptor. How the two differ

Valid MCP handshake	10/10	initialize and tools/list both answered.
Live MCP endpoint	25/25	Endpoint answers the MCP initialize handshake (2473 ms).
Protocol revision	8/10	Speaks MCP 2025-11-25, 1 revision(s) behind 2026-07-28.
Signed descriptor	n/a	No MCP standard defines a signed server descriptor.
Uptime (30 days)	15/15	31/31 probes succeeded over 30 days (100%).
Tool declaration	10/10	Lists 15 tool(s) with descriptions.
Verified identity	5/10	Publisher declared (repository, package or homepage); claim this listing to verify domain control.
Freshness + modern flags	4/5	seen in a source within 7 days.
Auth declaration	2/5	Declares credential scheme: smithery_api_key.

Applicable criteria total 90 points, scaled to 100.

Responsiveness: Responsive (2473 ms; bands ≤2.5 s, ≤5 s, ≤8 s, slower; penalty only).

Measured 2026-11-11.

Nine criteria, the same as the A2A readiness score, read from our daily MCP probe (initialize + tools/list) and 30-day probe history. No MCP standard defines a signed server descriptor, so that criterion is n/a and the other 90 points are scaled to 100. Grades: A>=90, B>=75, C>=60, D>=40, F<40. Display only: search order uses the quality grade.

Compared with peers

Against 53,039 reachable MCP servers in our daily snapshot (2026-11-12 06:46 UTC). Display only; it does not change search order.

Readiness: Higher than 95% of peers; This listing 88 · peer median 81
Latency: Faster than 31% of peers; This listing 493 ms · peer median 326 ms

Where it loses the most points, and how to win them back

Verified identity −5 — Claim the listing and prove control of its domain.
Now: Publisher declared (repository, package or homepage); claim this listing to verify domain control.
Auth declaration −3 — State how to authenticate (an auth scheme, or that none is needed).
Now: Declares credential scheme: smithery_api_key.
Protocol revision −2 — Support the current protocol revision.
Now: Speaks MCP 2025-11-25, 1 revision(s) behind 2026-07-28.

How many agent tools actually work · All statistics

Listed in

Directories this entry was found in.

smithery since 2026-06-04 ↗

How to connect

MCP endpoint (streamable-http)

https://server.smithery.ai/emailens-mcp/emailens-mcp/mcp

JSON-RPC initialize probe

curl -X POST https://server.smithery.ai/emailens-mcp/emailens-mcp/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}'

Homepage

https://emailens.dev/mcp

Listed at (smithery)

https://emailens.dev/mcp