HTML Field Types

Text, email, number, and textarea

<input name="full_name" type="text" />
<input name="email" type="email" />
<input name="age" type="number" />
<textarea name="message"></textarea>

Each field becomes a string value in the submission data.

Radio buttons

<label><input type="radio" name="plan" value="basic" /> Basic</label>
<label><input type="radio" name="plan" value="pro" /> Pro</label>

Only the selected value is submitted. The key is plan and the value is the chosen option.

Checkboxes

<label><input type="checkbox" name="newsletter" value="yes" /> Subscribe</label>

If checked, the value is sent. If unchecked, the key is omitted entirely.

Select menus

<select name="country">
  <option value="us">United States</option>
  <option value="ca">Canada</option>
</select>

The selected option value is stored under country.

File inputs

<input name="resume" type="file" />

Files are uploaded and stored as URLs. Formbase sets either the file or image key based on the MIME type.

Multiple values with the same name

When using multipart/form-data, repeated keys collapse to the last value. If you need arrays (for example, multi-select or checkbox groups), submit as JSON instead.

await fetch('https://formbase.dev/s/YOUR_FORM_ID', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ tags: ['design', 'growth', 'product'] }),
});

JSON submissions are best when you need structured data or arrays. Browser form posts are best for simple, classic form flows.

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FAQ

Multiple values with the same name

​Multiple values with the same name

Multiple values with the same name