> For the complete documentation index, see [llms.txt](https://docs.apryse.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.apryse.com/web/get-started/guides/features/basics/save.md).

# Serialization / Saving PDFs using JavaScript

Learn how to efficiently serialize PDF documents with Apryse SDK. Benefit from incremental save, linearization, and support for compressed object streams. Serialize to memory, stream, or disk with eas

{% hint style="warning" %}
Make sure you have [Full API enabled in WebViewer.](/web/what-is-webviewer/full-api.md)
{% endhint %}

Serialization also known as saving provides the ability to write content back to a storage medium.

Apryse SDK benefits include:

* Incremental save (for fast save and document persistence)
* Linearization (Fast Web View)
* Supports compressed object streams
* Unused object removal. This option can help you create smaller files
* Serialize a document to memory, stream, or a file on disk

## Save a document

To save a PDF document.

{% tabs %}
{% tab title="JavaScript" %}
{% code lineNumbers="true" %}

```js
async function main() {
  const doc = await PDFNet.PDFDoc.createFromURL(filename);

  // save the document to a memory buffer
  const buf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_linearized);

  //optionally save the blob to a file or upload to a server
  const blob = new Blob([buf], { type: 'application/pdf' });
}
PDFNet.runWithCleanup(main);
```

{% endcode %}
{% endtab %}
{% endtabs %}

[Read & write a PDF file from/to memory buffer](/web/get-started/samples.md#pdfdocmemory) Full source code which illustrates how to read/write a PDF document from/to memory buffer. This is useful for applications that work with dynamic PDF documents that don't need to be saved/read from a disk.

## About saving a document

PDF document can be serialized (or saved) to a file on a disk, to a memory buffer, or to an arbitrary data stream such as `MemoryFilter` or a `custom filter`.

To save a PDF document to a file on disk, invoke its `Save()` method:

{% tabs %}
{% tab title="JavaScript" %}
{% code lineNumbers="true" %}

```js
async function main() {
  const buf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_linearized);

  //optionally save the blob to a file or upload to a server
  const blob = new Blob([buf], { type: 'application/pdf' });
}
PDFNet.runWithCleanup(main);
```

{% endcode %}
{% endtab %}
{% endtabs %}

The second argument is a bitwise disjunction of flags used as options during serialization.

Apryse SDK allows a document to be saved incrementally (see section 2.2.7 "Incremental Update" in the PDF Reference Manual). Because applications may allow users to modify PDF documents, users should not have to wait for the entire file (which can contain hundreds of pages) to be rewritten each time modifications to the document are saved. Apryse SDK allows modifications to be appended to a file, leaving the original data intact. The addendum appended when a file is incrementally updated contains only those objects that were actually added or modified. Incremental update allows an application to save modifications to a PDF document in an amount of time proportional to the size of the modification rather than the size of the file. In addition, because the original contents of the document are still present in the file, it is possible to undo saved changes by deleting one or more file updates.

Changes can be appended to an existing document using `e_incremental` flag:

{% tabs %}
{% tab title="JavaScript" %}
{% code lineNumbers="true" %}

```js
async function main() {
  const buf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_incremental);

  //optionally save the blob to a file or upload to a server
  const blob = new Blob([buf], { type: 'application/pdf' });
}
PDFNet.runWithCleanup(main);
```

{% endcode %}
{% endtab %}
{% endtabs %}

Note that the file output name matches the input name.

Over time, PDF documents may accumulate unused objects like old updates, modifications, unused fonts, images, and so on. To trim down the file size by removing these unused objects, use the `e_remove_unused` flag:

{% tabs %}
{% tab title="JavaScript" %}
{% code lineNumbers="true" %}

```js
async function main() {
  const buf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_remove_unused);

  //optionally save the blob to a file or upload to a server
  const blob = new Blob([buf], { type: 'application/pdf' });
}
PDFNet.runWithCleanup(main);
```

{% endcode %}
{% endtab %}
{% endtabs %}

A PDF document can also be serialized into a memory buffer as follows:

{% tabs %}
{% tab title="JavaScript" %}
{% code lineNumbers="true" %}

```js
async function main() {
  const buf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_linearized);
}
PDFNet.runWithCleanup(main);
```

{% endcode %}
{% endtab %}
{% endtabs %}


---

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```
GET https://docs.apryse.com/web/get-started/guides/features/basics/save.md?ask=<question>&goal=<endgoal>
```

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