HTML Elements

<form>

HTML element · 11 supported, 2 partial, 8 unsupported across 21 clients

11 of 21 email clients render <form> fully (Sep 2, 2026 data); it breaks outright in Outlook (New), Outlook Classic, Outlook for Mac and 5 more.

3/7 webmail, 2/6 desktop, 6/8 mobile clients support <form> fully.
Unsupported in Outlook (New), Outlook Classic, Outlook for Mac, Yahoo Mail iOS and 4 more.
Partial in Gmail iOS, Outlook 365, behavior differs from browsers, test before relying on it.
Outlook Classic (Word engine, supported to at least 2029) does not fully support <form>, and its replacement changes little here; see the deprecation diff.
Documented before/after fixes on this page cover 21 clients, including Gmail and Gmail Android.
Across all clients, only 6 of 298 tracked HTML/CSS features render identically everywhere.

Source: caniemail.com (MIT), via the Emailens engine. Last tested upstream Sep 10, 2019, synced by Emailens Sep 2, 2026.

Client Support

Client	Category	Engine	Support
Gmail	webmail	Gmail Web	Supported
Gmail Android	mobile	Gmail Mobile	Supported
Gmail iOS	mobile	Gmail Mobile	Partial^{See caveat 1}
Outlook 365	webmail	Outlook Web	Partial^{See caveat 2}
Outlook (New)	desktop	Outlook Web	Unsupported
Outlook Classic	desktop	Microsoft Word	Unsupported
Outlook iOS	mobile	Outlook Mobile	Supported
Outlook Android	mobile	Outlook Mobile	Supported
Outlook for Mac	desktop	WebKit	Unsupported
Apple Mail	desktop	WebKit	Supported
Apple Mail iOS	mobile	WebKit	Supported
Yahoo Mail	webmail	Yahoo	Supported
Yahoo Mail Android	mobile	Yahoo	Supported
Yahoo Mail iOS	mobile	Yahoo	Unsupported
Samsung Mail	mobile	Samsung	Supported
Thunderbird	desktop	Gecko	Supported
HEY Mail	webmail	WebKit	Unsupported
Proton Mail	webmail	Proton	Unsupported^{See caveat 3}
AOL Mail	webmail	AOL	Supported
Fastmail	webmail	Fastmail	Unsupported
Superhuman	desktop	Blink	Unsupported

Documented caveats (3)

1.Gmail iOS: Does not submit in iOS with non Google accounts.
2.Outlook 365: Not supported. The <form> is there but values are not submitted.
3.Proton Mail: Not supported. The <form> and its entire content is removed.

Caveats recorded by caniemail.com (MIT) and carried verbatim, one entry per wording rather than per client.

Client-by-client behaviour for <form>

Fully supports <form> (11): Gmail, Gmail Android, Outlook iOS, Outlook Android, Apple Mail, Apple Mail iOS, Yahoo Mail, Yahoo Mail Android, Samsung Mail, Thunderbird, AOL Mail.

Partial support (2): Gmail iOS, Outlook 365. Expect rendering quirks unique to each engine. Partial support typically means a subset of values, an ignored shorthand, or sanitizer-specific rewrites.

No support (8): Outlook (New), Outlook Classic, Outlook for Mac, Yahoo Mail iOS, HEY Mail, Proton Mail, Fastmail, Superhuman. Plan fallbacks for these clients before relying on <form> in production sends.

Fixes & Workarounds

Outlook (New)

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Outlook Classic

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Outlook for Mac

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Yahoo Mail iOS

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

HEY Mail

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Proton Mail

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Fastmail

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Superhuman

Unsupported

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Gmail iOS

Partial

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Outlook 365

Partial

Use links to a web form instead of embedding forms in email.

Before (Broken)

before.html

4 lines

<form action="/subscribe" method="POST">
  <input type="email" placeholder="Email" />
  <button type="submit">Subscribe</button>
</form>

After (Fixed)

fixed.html

13 lines

<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>

Replace embedded form with a link to a hosted form

Production guidance for <form>

<form> is a HTML element. Across the email client matrix, 11 of 21 tracked clients support it fully, 2 only partially, and 8 not at all. The clients most likely to require a workaround for this feature are Outlook (New), Outlook Classic, Outlook for Mac. Each of them needs a tailored fallback. See the per-client examples above for the specific code fix Emailens recommends.

When in doubt, ship a baseline that renders without <form> and treat it as progressive enhancement on clients where support is verified. Emailens automatically detects cross-client divergence on this feature when you preview an email, so you can see exactly which template paths break before a campaign goes out.

Related Features

Check your own HTML for <form>

Paste your own, or run the sample below. Analyzed in this page, with no signup and nothing stored.

Zero-Friction Engine Preview

Test your <form> layout across 21 email clients

Preview rendering, catch CSS issues, and see how <form> displays across Outlook, Gmail, and Apple Mail. Free, no account needed.

Instant live preview · No signup required · 21 email engines

Last tested upstream: Sep 10, 2019 · Last synced by Emailens: Sep 2, 2026

caniemail.com (MIT) records Sep 10, 2019 as the last time <form> was tested in a real client, 6 years before this sync. Syncing copies that result forward, it does not re-test it. Carried in @emailens/engine data v0.12.2.