Free macOS-native email builder for designing on-brand emails by hand, with your own AI API key, or via MCP from coding agents.
Maildun homepage — email marketing tools, built in the open
1 / 3Overview
What is Maildun for Mac?
Email marketing tools, built in the open.
Maildun for Mac is a free, native macOS email builder for designing on-brand emails three ways: by hand with drag-and-drop, with AI using your own API key, or over MCP from coding agents.
The native editor offers Design, Preview, and Code modes with desktop and mobile previews. The AI design assistant plugs in your own Claude, ChatGPT, Gemini, or Grok API key — every change appears as a proposal you accept or reject. A built-in MCP server lets Claude Code, Codex, and Cursor list, create, and edit emails inside your current workspace without Node.js.
Each client gets its own workspace with a brand kit (colors, fonts, Markdown brand guide, shadcn-style component styles) and one-click Apply brand restyling. Reusable sections, WebP image conversion uploaded to your own Cloudflare R2 or Amazon S3 bucket, and template publishing to maildun.com round it out. The full platform is open source (AGPL-3.0) and self-hostable.
Maildun for Mac is completely free; voluntary pay-what-you-want tips are optional. Designs and settings stay on your Mac, API keys live in the macOS Keychain, and there is no analytics or telemetry.
Platforms and languages
Maildun for Mac Availability
Platforms
Languages
Capabilities
Maildun for Mac Key Features
macOS-native builder
Native drag-and-drop email editor with Design, Preview, and Code modes plus desktop and mobile previews.
AI design assistant
Connect your own Claude, ChatGPT, Gemini, or Grok API key; every edit appears as a proposal you accept or reject.
Built-in MCP server
Claude Code, Codex, and Cursor can list, create, and edit emails in your workspace — no Node.js required.
Brand kits and workspaces
Per-client workspaces with brand kits (colors, fonts, Markdown brand guide, shadcn-style components) and one-click Apply brand restyling.
Reusable sections and self-owned media
Save reusable sections; images convert to WebP locally and upload to your own Cloudflare R2 or Amazon S3 bucket; export and publish templates to maildun.com.
Best for
Who uses Maildun for Mac?
Indie developers
Design on-brand marketing emails locally with AI assistance or coding agents
Freelancers and agencies
Manage per-client workspaces and brand kits for email campaigns
Email marketers
Build templates by hand or with AI and publish them to maildun.com
Plans and access
Maildun for Mac Pricing
Free
Completely free; voluntary pay-what-you-want tips, $0 also works
Common questions
Maildun for Mac FAQs
Is Maildun really free?
Yes — Maildun for Mac is completely free. Optional pay-what-you-want tips unlock nothing extra; $0 works fine.
How does the AI assistant work, and what does it cost?
Plug in your own Claude, ChatGPT, Gemini, or Grok API key. AI costs are billed by your chosen provider under their terms; review AI output before accepting and sending.
Can coding agents edit my emails?
Through the built-in MCP server — Claude Code, Codex, Cursor, and other coding agents can list, create, and edit emails in your current workspace, no Node.js needed.
Is my data private?
Your designs and settings live on your Mac, API keys are stored in the macOS Keychain, prompts go directly from your Mac to the AI provider, and the app ships no analytics or telemetry. The MCP server only listens on localhost.
Is Maildun open source, and how do updates work?
The platform code is open source under AGPL-3.0 (github.com/Maildun/maildun) and self-hostable. The app checks GitHub for updates on launch and every few hours; auto-install can be turned off in-app.
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