Form Fields

html.contact reads normal HTML form fields. Every field you want to collect needs a name attribute.

Normal submitted fields

Most forms should use ordinary field names:

• name
• email
• message
• optional subject
• any custom field names your form needs

html.contact stores submitted values by field name. For text fields, the stored value is what the visitor typed. For selects, radios, and checkboxes, the stored value is the submitted value.

<label for="budget">Budget</label>
<select id="budget" name="budget">
  <option value="under-5k">Under $5k</option>
  <option value="5k-15k">$5k - $15k</option>
  <option value="15k-plus">$15k+</option>
</select>

If the visitor chooses “Under $5k”, html.contact stores budget with the value under-5k.

Custom fields

Unknown field names are preserved in submitted data, submission detail, private API responses, and CSV exports.

The dashboard table shows a small set of common fields first, such as name, email, subject, message, and phone. It does not show every custom field as a table column at once.

Duplicate field names are stored as multiple values. This is useful for checkbox groups:

<label>
  <input type="checkbox" name="services" value="Design">
  Design
</label>

<label>
  <input type="checkbox" name="services" value="Development">
  Development
</label>

If both are selected, both values are preserved.

Subject and intro

Use subject without an underscore when the submitted form should set the notification email subject.

Subject priority:

1. Submitted subject field.
2. The form’s default subject setting.
3. New submission from {form name}.

The form’s default intro is different. When configured, it is always shown at the top of notification emails for that form. A submitted _intro field is stored as a normal submitted field, but it does not override the default intro.

Reply-To

Use _replyto when you want replies to go to the person who submitted the form.

<input type="hidden" name="_replyto" value="email">

_replyto can be:

• a literal email address, such as support@example.com
• the name of a submitted field, such as email

If _replyto is absent, html.contact can infer Reply-To from common submitted email field names such as email, Email, your_email, your-email, reply_to, replyTo, and contact_email.

Redirects

After a successful browser post, html.contact can show its normal success response or redirect the visitor.

Redirect priority:

1. Submitted _redirect.
2. The form’s Redirect URL setting.
3. Normal html.contact success response.

<input type="hidden" name="_redirect" value="https://example.com/thanks">

If the chosen redirect URL is unsafe, html.contact shows the normal success response instead of falling back to another redirect.

Reserved system fields

These field names are read by html.contact and stored separately from normal submitted fields:

Field	What html.contact does
_redirect	Considers this URL for post-submit redirect before the form’s Redirect URL setting.
_replyto	Sets Reply-To from a literal email address or from another submitted field.
_gotcha	Honeypot field. Filled values are rejected before email delivery.
form_key	Public form key used by the /submit compatibility endpoint.
_form_name	Reserved metadata field. It does not rename the form in your account.
_source	Reserved metadata field. It does not replace browser source checks.
_tag	Reserved metadata field. It does not route email.
cf-turnstile-response	Reserved for customer-managed challenge data. Default snippets do not require CAPTCHA or Turnstile.

Fields that do not control email

These fields are allowed, but they are stored as ordinary submitted fields only:

• _subject
• _intro
• _to
• _cc
• _bcc
• _from

_subject does not set the notification subject. Use subject without the underscore.

_intro does not override the form’s default intro.

_to, _cc, _bcc, and _from never control recipients, CC/BCC, sender identity, Reply-To, or routing. Recipients are configured inside html.contact.

File fields

File inputs require enctype="multipart/form-data".

<form
  action="https://html.contact/f/hc_pub_REPLACE"
  method="POST"
  enctype="multipart/form-data"
>
  <input id="attachment" name="attachment" type="file">
  <button type="submit">Send</button>
</form>

The file input still needs a name. The uploaded filename is stored with the submitted fields under that field name.

Current browser form support allows one non-empty attachment per submission, up to 4 MB.