# HTML forms

Connect a plain HTML form to Nisuform with the action attribute. No JavaScript, server or build step needed.

Any HTML form can send submissions to Nisuform. Set the form's `action` to your endpoint and its `method` to `POST`.

```html
<form action="https://api.nisuform.com/s/YOUR_FORM_KEY" method="POST">
  <label for="name">Name</label>
  <input id="name" type="text" name="name" required>

  <label for="email">Email</label>
  <input id="email" type="email" name="email" required>

  <label for="message">Message</label>
  <textarea id="message" name="message" rows="5" required></textarea>

  <input type="text" name="_gotcha" tabindex="-1" autocomplete="off" style="display:none">
  <button type="submit">Send</button>
</form>
```

Copy your endpoint from the form's **Setup** tab, or from **Settings**, **Endpoint**.

## Name every field

The browser only sends inputs that have a `name`. The name becomes the key the answer is saved under, and the inbox shows it as the label unless your form builder gives the field a nicer one.

* If your form has fields in the [form builder](/docs/forms/builder), use the same names so Nisuform can validate the answers. The **Field name** of each field is shown in the builder.
* Inputs that the builder does not list are still saved as they are. You never lose data because of a missing field.
* Names that start with an underscore, like `_gotcha`, control how Nisuform handles the submission and are not saved. See [Special fields](/docs/connect/special-fields).

## Multiple values

Checkboxes that share a name, and names that end in `[]`, are saved as one comma-separated answer:

```html
<fieldset>
  <legend>Topics</legend>
  <label><input type="checkbox" name="topics[]" value="Design"> Design</label>
  <label><input type="checkbox" name="topics[]" value="Development"> Development</label>
  <label><input type="checkbox" name="topics[]" value="Marketing"> Marketing</label>
</fieldset>
```

Checking the first two saves `topics` as `Design, Development`.

## Hidden fields

Use hidden inputs to record where a submission came from. They are saved like any other field:

```html
<input type="hidden" name="source" value="pricing-page">
<input type="hidden" name="plan" value="team">
```

Nisuform also records the page the form was sent from on its own. The inbox shows it as **Page** on every submission.

## What visitors see

After a normal browser submit, Nisuform answers with a thank-you page that links back to the page the visitor came from. On Pro you can replace it with your own title and message or redirect to a page on your site. See [Thank-you page and redirects](/docs/forms/after-submit).

If a submission is rejected, for example because the form is closed or the visitor sent too many requests, the visitor sees a short page that explains why, with a link back to your site.

## File inputs

To accept files, the form needs `enctype="multipart/form-data"` and file uploads must be turned on for the form. Uploads are a Pro feature. See [File uploads](/docs/connect/file-uploads).

## Sizes and limits

* Up to 50 fields per submission. Extra fields are ignored.
* Field names up to 200 characters.
* Values up to 10,000 characters. Longer values are cut at 10,000.
* The whole request can be up to 200 KB, or 25 MB on forms that accept file uploads.

## Opening the endpoint in a browser

The endpoint only accepts `POST`. If you open it in a browser tab you see a short page that explains it is a form endpoint, with status `405`. That is expected and does not mean anything is broken.