> ## Documentation Index
> Fetch the complete documentation index at: https://developers.tally.so/llms.txt
> Use this file to discover all available pages before exploring further.

# Collect the respondent's IP address

> Capture the respondent IP address into a hidden field using custom domain code injection.

<Warning>
  **Privacy and security:** capturing the visitor's IP address has privacy implications. Make sure
  to inform users and obtain consent where it's required.
</Warning>

This example requires a [custom domain](https://tally.so/help/custom-domains) and
[code injection](/widgets/code-injection). Paste the snippet below into the **Code
injection** box of your custom domain settings, and replace the input's ID with the one
from your form.

1. Add a **Short text** field at the beginning of your form — this is what we'll write the
   IP into.
2. Open the form in preview mode and grab the input's UUID from the rendered HTML.
3. Paste the script and swap in the UUID.

```javascript theme={null}
const getIPAddress = async () => {
  try {
    const response = await fetch('https://api.ipify.org?format=json');
    if (!response.ok) {
      throw new Error('Network response was not ok');
    }
    const data = await response.json();
    return data.ip;
  } catch (error) {
    console.error('Error fetching the IP address:', error);
    throw error;
  }
};

document.addEventListener('DOMContentLoaded', async () => {
  // Replace this UUID with the one of the Short text field you added
  const ipInput = document.getElementById('c1cbc8e4-b2f3-4e63-a683-ec9eadbcb022');
  if (!ipInput) {
    return;
  }

  // Hide the input so it's not visible in the form
  ipInput.style.display = 'none';

  // Get the IP address of the visitor
  const ip = await getIPAddress();

  // This is necessary to bubble the event up to the input and update the React app state
  const nativeInputValueSetter = Object.getOwnPropertyDescriptor(
    window.HTMLInputElement.prototype,
    'value',
  ).set;
  nativeInputValueSetter.call(ipInput, ip);
  ipInput.dispatchEvent(new Event('input', { bubbles: true }));
});
```