This post tells you how to generate emails on Node.js and open them in an email program. It uses mailto URLs to do so. The advantage of this approach is that you can manually check and edit such emails before sending them.

mailto URL syntax

"mailto:" recipients ( "?" key "=" value ("&" key "=" value)* )?

• recipients: comma-separated email addresses (no spaces; Outlook needs semicolons instead of commas)
• value: should be URL-encoded (e.g. space becomes %20)
• key: subject, cc, bcc, body

Example: mailto:joe@example.com,jane@example.com?subject=hello&body=How%20are%20you%3F

Using mailto URLs on Node.js

The npm module openurl allows you to tell the operating system to open a URL. It also comes with a mailto() function that constructs well-formed mailto URLs. Example:

    require("openurl").mailto(["john@example.com", "jane@example.com"],
        { subject: "Hello!", body: "This is\na generated email!\n" });

Naturally, the same technique also works with other programming languages:

• A simple way of sending emails in Java: mailto links
• Generate emails with mailto URLs and Python