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Mailto Link Builder

Generators

Everything runs locally in your browser — nothing is uploaded

Input
Drop a file here to load its contents
Output

`mailto:` is one of the few protocols that still opens a mail client with one click, but its parameter rules are counter-intuitive and hand-writing one usually goes wrong. This tool assembles recipients (the header) with cc, bcc, subject and body (query parameters), and handles three things people miss: a body newline must be `%0D%0A` (a bare `%0A` is dropped by some clients), `&`, `?` and `#` in the subject or body must be encoded, and a link longer than about 2,000 characters gets truncated silently, so it warns you. Whether to join addresses with `,` or `;` (Outlook only accepts `;`) is a choice.

Features

  • One recipient per line, assembled into a mailto link
  • Cc, bcc, subject and body all supported
  • Body newlines encoded as %0D%0A so clients do not drop them
  • Automatic encoding of & ? # in the subject and body
  • A warning above about 2,000 characters, where truncation happens
  • Choose , or ; as the address separator (Outlook needs ;)
  • Every parameter broken out for checking
  • A subject with no recipient still works (mailto:?subject= is valid)

How to use

  1. Type one recipient email per line
  2. Fill in cc, bcc, subject and body as needed (use \n for a new line)
  3. Switch the separator to semicolon for Outlook compatibility
  4. Copy the link into a page, an email or a document

FAQ

Why does a body newline have to be %0D%0A?
A mailto body travels URL-encoded, and the canonical line break is carriage return plus line feed, which is `%0D%0A`. A bare `%0A` is ignored by some clients, squashing your careful lines together. The tool turns both real newlines and literal `\n` into `%0D%0A`.
Comma or semicolon?
RFC 6068 allows both, but Outlook only accepts the semicolon. Choose `;` if Outlook matters; `,` is more common for web pages, Gmail and Apple Mail. Multiple recipients and cc addresses are joined with whichever you pick.
Why warn when the link is long?
Browsers and mail clients all have practical length limits for `mailto:` (the exact number varies). Past that, nothing errors — the link is quietly truncated, so the body arrives half-finished. Above about 2,000 characters the tool warns; an attachment or a shorter body is safer.

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