Emailens MCP

Analyze, audit, fix and diff HTML, MJML, Maizzle and React Email across 21 email clients.

CommunityDegradedNo sign-inGlobalFreeRead-only

What it can do

    What data it sees

    Do you need an account

    No: the server works without sign-in

    Analyze, audit, fix and diff HTML, MJML, Maizzle and React Email across 21 email clients.

    How to connect

    How to connect Emailens MCP to Claude

    The server address to paste into Claude settings:

    https://emailens.dev/api/mcp

    1. Open Claude (claude.ai or the desktop app).
    2. Go to Settings → Connectors.
    3. Click Add custom connector.
    4. Paste the server address copied below into Remote MCP server URL and click Add.
    5. In a chat, click + → Connectors and switch the new connector on.

    Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.

    Authorization

    After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.

    How to connect Emailens MCP to ChatGPT

    The server address to paste into ChatGPT settings:

    https://emailens.dev/api/mcp

    1. Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
    2. Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
    3. Open Settings → Connectors and click Create.
    4. Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
    5. Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
    6. In a new chat open + → Apps/Connectors and enable the connector.

    OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.

    Authorization

    On first use ChatGPT opens the service's sign-in window. Sign in and approve access.

    How to connect Emailens MCP to Cursor

    The server address to paste into Cursor settings:

    https://emailens.dev/api/mcp

    Fastest: click Open in Cursor below and confirm the prompt.

    Manually:

    1. In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
    2. Paste the JSON copied below into ~/.cursor/mcp.json (per project: .cursor/mcp.json in the repo root).
    3. Save the file. The server appears in the MCP list; authorize it there if asked.

    Authorization

    If the service needs sign-in, an authorize button appears next to the server in the MCP list.

    Server tool list (9)

    Raw names from tools/list. Only developers need these.

    preview_emailFull email compatibility preview , transforms HTML for 21 email clients, analyzes CSS, generates scores, simulates dark mode, checks inbox preview and email size.
    analyze_emailQuick CSS compatibility analysis , returns warnings and per-client scores.
    audit_emailComprehensive quality audit , CSS compatibility, spam, links, accessibility, images, inbox preview, size, templates, content overflow, visual bugs.
    fix_emailGenerate a structured fix prompt for email compatibility issues.
    list_clientsList all 21 supported email clients with IDs, names, rendering engines, dark mode support, and deprecation status. Use the returned IDs to filter other tools like preview_email or capture_screenshots.
    diff_emailsCompare two email HTML versions , shows score changes, fixed issues, and regressions per client.
    check_deliverabilityCheck email deliverability for a domain , SPF, DKIM, DMARC, MX, BIMI.
    build_emailGenerate a cross-client-compatible email from a brief using Emailens's self-healing loop (generate → score across 21 clients → repair). Output stays in the framework you choose. Returns a runId immediately , poll get_build_status for progress and the final code. Requires a Pro/Team API key.
    get_build_statusCheck a build_email run by runId , returns status, iteration, best compatibility score, and the current best source once available.