---
title: "Media type"
source: https://dev.pageseeder.com/reference/glossary/media_type.html
description: "PageSeeder uses media types to trigger document processors for handling specific formats like XML and PDF. Media types consist of a general category and specific subtype separated by a slash, with PageSeeder defining a vendor-specific type for PSML documents. File extensions determine media type mapping."
last_updated: 2026-09-08T11:50:22+10:00
tokens: ~545
---

# Media type

PageSeeder uses the media type of a [document](/reference/glossary/document.md) as a trigger to invoke document processors that have specific capabilities to process data formats such as XML or [PDF](/reference/glossary/pdf_documents.md).

Every PageSeeder document or configuration file has a media type. To help you identify the media type quickly, documents titles or file names are almost always preceded by a [media icon](/reference/glossary/media_icon.md) in the user interface.

A media type has two main parts separated by a '/'. The first part defines the general category such as audio content, executable program, image, text message, video stream, etc. The second part provides a specific subtype defined by the file format.

There is an [official register of media types](https://www.iana.org/assignments/media-types/media-types.xhtml) maintained by IANA.

PageSeeder also defines a vendor-specific media type for [PSML](/reference/glossary/psml.md):

`application/vnd.pageseeder.psml+xml`

For further information, *see* the articles on [MIME properties](/guide/configuration/properties/mime_properties.md).

> **Tip:** Project [managers](/reference/glossary/manager.md) can configure media fragments in the [document template](/reference/glossary/document_template.md) using the [\<media-fragment\>](/psml/elements/element_media-fragment.md) element.

## File extension mapping

PageSeeder doesn’t inspect the content of every file. In most situations, it relies on the file extension to determine what the media type is. For that reason, it is important that files uploaded into PageSeeder use file extensions consistently.

> **Tip:** Prefer using lower case extension "`.png`" to the upper case version. Although, it might work in some circumstances, avoid using a mixed case "`.Jpeg`".

Administrators can access PageSeeder media type mapping to file extensions in the **server properties page**. There is no need to change this mapping – it is provided for your information only.

Contact support, if you require an [IANA registered media type](https://www.iana.org/assignments/media-types/media-types.xhtml) to be mapped to a file extension.