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HTML element · data last changed 10 Nov 2026

<form> in email clients

Works in 10 of 21. Not supported in Outlook Classic, Yahoo Mail, Yahoo Mail iOS and 4 more. Partial in Gmail iOS, Outlook 365, Outlook (New) and 1 more.

Your reader in Outlook Classic sees the email without <form>, even if it looks right where you tested it.

caniemail (MIT) via @emailens/engine 0.18.22

The fix for Outlook Classic

Replace embedded form with a link to a hosted form

after 
<table role="presentation" cellpadding="0" cellspacing="0">
  <tr>
    <td style="background-color: #6d28d9; border-radius: 6px;
               padding: 12px 32px;">
      <a href="https://example.com/subscribe"
        style="color: #fff; text-decoration: none;
               font-family: Arial, sans-serif;
               font-weight: bold;">
        Subscribe Now
      </a>
    </td>
  </tr>
</table>
Show the original
before 
<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

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<form> is not among the 24 features we have screenshotted on real installs. The ones we have →

All 21 clients, problems first

ClientSupport
Outlook Classic Not supported
Yahoo Mail Not supported See caveat 3
Yahoo Mail iOS Not supported
HEY Mail Not supported
Proton Mail Not supported See caveat 4
Fastmail Not supported
Superhuman Not supported
Gmail iOS Partial See caveat 1
Outlook 365 Partial See caveat 2
Outlook (New) Partial See caveat 2
Outlook for Mac Partial See caveat 2
Works in 10: Gmail, Gmail Android, Outlook iOS and 7 more. Show all
ClientSupport
Gmail Works
Gmail Android Works
Outlook iOS Works
Outlook Android Works
Apple Mail Works
Apple Mail iOS Works
Yahoo Mail Android Works
Samsung Mail Works
Thunderbird Works
AOL Mail Works

Caveats (4)

  1. 1. Gmail iOS: Does not submit in iOS with non Google accounts.
  2. 2. Outlook 365, Outlook (New), Outlook for Mac: Not supported. The <form> is there but values are not submitted.
  3. 3. Yahoo Mail: Observed 2026-10-29 (Emailens probe, Yahoo Mail web (Chrome), our own seed inbox): The form is kept but its action is removed (absolute, relative and empty alike), and so is formaction on a button; Yahoo adds target="_blank". The form cannot reach your server: link to a landing page instead. type="email" is also dropped from inputs; method, text, radio and submit inputs are kept.
  4. 4. Proton Mail: Not supported. The <form> and its entire content is removed.

Caveats as recorded by caniemail (MIT), one entry per wording.

How <form> behaves

A <form> in an email submits only in Gmail on the web and Android, Apple Mail, Apple Mail iOS, Samsung Mail, Thunderbird, AOL Mail, Yahoo Mail Android and the Outlook apps for iOS and Android. Outlook 365, Outlook (New) and Outlook for Mac show the form but send no values, and Outlook Classic, Yahoo Mail on the web and iOS, Proton Mail, HEY Mail, Fastmail and Superhuman do not support it.

  • Yahoo Mail on the web keeps the form but removes its action, whether absolute, relative or empty, and removes formaction from buttons. It also adds target="_blank" and drops type="email" from inputs. We read this from the delivered HTML on October 29, 2026. The form cannot reach your server.
  • Proton Mail removes the <form> and everything inside it, so any question or button inside the form disappears too.
  • Outlook 365, Outlook (New) and Outlook for Mac render the form, but submitting it sends no values.
  • Gmail iOS does not submit forms for non-Google accounts.

Replace the form with links. For a rating, make each score a link to a landing page that records the answer. For a sign-up, link a button to a hosted form. Links work in every client, so every reader can answer, and nobody sees a form that does nothing.

Questions

Can you put a form in an HTML email?

You can, but it submits only in some clients. Outlook Classic, Yahoo Mail on the web, Proton Mail, HEY Mail, Fastmail and Superhuman do not support it, and Outlook 365, Outlook (New) and Outlook for Mac send no values. Link to a hosted form instead.

Do forms work in Gmail?

Gmail on the web and Gmail Android submit them. Gmail iOS does not submit for non-Google accounts.

Your next question

<form> in Outlook Classic · Every feature in Outlook Classic · All email CSS features · What real installs show

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caniemail (MIT) via @emailens/engine 0.18.22 · tested upstream 10 Sep 2019 · data last changed 10 Nov 2026 · Outlook (New) cells are the engine's mapping