---
title: "Headless JavaScript PDF form fill library"
canonical_url: "https://www.nutrient.io/guides/web/forms/fill-form-fields/headless/"
md_url: "https://www.nutrient.io/guides/web/forms/fill-form-fields/headless.md"
last_updated: "2026-06-09T10:14:21.508Z"
description: "Fill PDF form fields programmatically without a UI using Nutrient Web SDK headless mode. Automate form completion and data population workflows with JavaScript."
---

# Headless form fill

It’s possible to apply PDF form fill operations without the need to present any user interface (UI) to the user.

## Standalone

In [Standalone mode](https://www.nutrient.io/guides/web/about/operational-modes.md) of Nutrient Web SDK, you can perform the operation using JavaScript in the browser by setting the `headless` option as `true` when loading the JavaScript library. This indicates you don’t want a UI:

```js

NutrientViewer.load({
    //...
    headless: true
}).then((instance) => {
    // Apply your operations.
}).catch((error) => {
    console.error("Failed to load viewer:", error.message);
});

```

Once the SDK is loaded, you can apply any of our operations as normal.

## Server-backed

When using the Server-backed [operational mode](https://www.nutrient.io/guides/web/about/operational-modes.md), a variety of operations are available server-side. Refer to the [Document Engine documentation](https://www.nutrient.io/guides/document-engine.md) for additional information.
---

## Related pages

- [Adding an image to a PDF form using JavaScript](/guides/web/forms/fill-form-fields/add-image.md)
- [Attach a file to a PDF form using JavaScript](/guides/web/forms/fill-form-fields/attach-a-file.md)
- [Detecting user inputs in PDF forms](/guides/web/forms/fill-form-fields/detect-user-input.md)
- [Dynamic font loading in PDF forms using Nutrient Web SDK](/guides/web/forms/fill-form-fields/dynamic-font-loading.md)
- [Import data into PDF forms using Instant JSON](/guides/web/forms/fill-form-fields/import-from-instant-json.md)
- [Import data into PDFs from a database](/guides/web/forms/fill-form-fields/import-from-database.md)
- [Import data into PDF forms using XFDF](/guides/web/forms/fill-form-fields/import-from-xfdf.md)
- [Import data into PDF form using Web SDK with Document Engine](/guides/web/forms/fill-form-fields/import-from-server-backed.md)
- [Customizing PDF form permissions](/guides/web/forms/fill-form-fields/permissions.md)
- [Fill PDF forms programmatically using JavaScript](/guides/web/forms/form-filling.md)
- [Fill PDF form fields using our JavaScript viewer UI](/guides/web/forms/fill-form-fields/using-the-ui.md)