What a mailto link actually is
A mailto link is a URL that, instead of pointing at a web page, asks the visitor's device to open its default mail app with a message already started. The address goes straight after the colon, and everything else, subject, body, cc and bcc, travels as query parameters: mailto:hello@example.co.uk?subject=Hi. Click it and a draft appears with those fields filled in, ready for the sender to finish and send from their own account. That last part is the point: the email comes from them, not from your website, so you get a real reply address without running any server code.
Everything on this page runs in your browser. Addresses, subjects and body text are never uploaded anywhere, and the test link simply hands the finished URL to your own mail app.
Getting the encoding right
The reason mailto links break is nearly always encoding. Spaces, ampersands and line breaks all have special meaning inside a URL, so they must be percent-encoded: a percent sign followed by the character's byte value in hexadecimal. Two rules matter more than the rest. First, spaces must become %20, not the plus sign used by web forms, because mail apps are not required to turn a plus back into a space. Second, line breaks in the body must be sent as %0D%0A, the carriage return and line feed pair, or your carefully spaced paragraphs arrive as one solid block.
The ampersand deserves special respect. Unencoded, it ends the current parameter and starts a new one, so a subject like "Terms & conditions" would silently lose everything after the ampersand. This tool encodes it as %26 automatically, along with everything else that needs it.
Where mailto links shine, and where they do not
They are ideal for contact links on websites and email signatures, support links that pre-fill a subject so replies sort themselves ("Order query: "), feedback links in apps and documents, and any situation where you want a person's own mail account to do the sending. Because there is no form and no server, there is nothing to maintain and nothing to spam-protect.
The limits are just as clear. Long bodies get truncated: some mail apps and browsers cut mailto URLs off at around 2,000 characters, so treat the body as a starter, not a letter. Attachments are impossible, by design. And the link opens whatever the device thinks is the default mail app, which on a shared or work computer may not be the app the visitor actually uses. For anything long, structured or mandatory, a proper contact form is the better tool.
Using the HTML snippet
The snippet is a ready-made anchor tag with the URL properly escaped for HTML, which matters because the raw ampersands that join mailto parameters must be written as & inside an attribute. Paste it into your page and change the link text to something descriptive: "Email our support team" tells both visitors and screen readers far more than "click here". If you also want the address visible on the page, put the address itself in the link text, but know that visible addresses attract scrapers, so a short human-readable label is usually the wiser choice.
Frequently asked questions
Why do spaces become %20 rather than a plus sign?
The plus-for-space convention belongs to web form submissions, not mailto links. Mail clients are not required to translate a plus back into a space, so a subject encoded with plus signs can arrive reading like Hello+there. Percent-encoding spaces as %20 works everywhere, which is why this tool uses it.
How do I put line breaks in the body?
Just press Enter in the body field. Each line break is encoded as %0D%0A, the carriage return and line feed pair the mailto standard expects, so the message opens in the mail app with your paragraphs intact. Typing %0D%0A by hand into the raw URL works too.
Can a mailto link add an attachment?
No. The mailto standard has no attachment mechanism, and for good reason: a web page should not be able to reach into someone's files. If you need people to send you a file, ask for it in the body text or use a proper upload form instead.
How do I send to more than one address?
Separate addresses with commas in the to, cc or bcc fields and the tool joins them correctly. Be careful with bcc: some mail clients ignore the bcc part of a mailto link entirely, so do not rely on it for anything important.
Is anything I type here uploaded?
No. The link is assembled entirely in your browser with JavaScript, so addresses, subjects and body text never leave your device. Clicking the test link simply hands the finished mailto URL to your own mail app.