OPML (Outline Processor Markup Language) is an XML format for outlines, often used for RSS feed lists.

Is the OPML Viewer free?

Yes, this tool is completely free and works offline once loaded—no signup or account is required.

What can I open with the OPML viewer online?

You can open any valid .opml file or pasted OPML/XML, including feed-reader subscription exports and outline documents, and view their full node hierarchy as a tree.

Can I view an OPML file as a mind map?

The viewer renders OPML as an expandable, collapsible tree that mirrors the outline hierarchy, giving you a mind-map-style overview of how nodes and sub-nodes are nested.

Is my OPML file uploaded to a server?

No. All parsing happens locally in your browser, so your OPML data is never sent to any server and stays on your device.

OPML Viewer - Free Online OPML File Viewer & Editor

Open OPML files online and view them as a tree structure. Inspect RSS feed subscriptions and analyze outlines in your browser, no signup required.

OPML Source

Drag & drop OPML file here

Structure Preview

Enter OPML content to view structure

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RSS Viewer

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XML Viewer Online

Open, view, and format XML files online with tree view and validation.

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OPML to JSON

Convert OPML outlines to JSON.

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XML to JSON

Convert XML string to JSON object.

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How to Use OPML Viewer?

Upload an OPML file or paste the XML content into the input area.
The tool will automatically parse and display the outline structure in the preview pane.
Expand or collapse nodes to explore the hierarchy.

Key Features

Instant Parsing

Quickly visualize complex OPML structures in a readable tree format.

RSS Feed Detection

Automatically identifies and links to RSS feeds within the outline.

Privacy Focused

All parsing happens locally in your browser. Your data is never sent to any server.

Upload or paste an OPML file and this viewer instantly renders it as an expandable tree, so you can inspect the outline hierarchy, read each node's title and text attributes, and follow detected RSS feed and website links. Parsing runs entirely in your browser with no signup, making it ideal for reviewing exported feed-reader subscription lists and mind-map outlines.

How to Use the OPML Viewer

1
Add your OPML
Drag and drop an .opml file, click Browse File to upload one, or paste raw OPML/XML directly into the input area.
2
Parse the outline
The viewer validates the <opml> root, then automatically parses the body and renders every outline node as a structured tree.
3
Explore the hierarchy
Expand or collapse nodes to navigate nested outlines, and open detected RSS feed or website links straight from each item.
4
Review document info
Check the head section for the title and metadata, and use the Sample button to load an example or Clear to start over.

References

OPML 2.0 Specification
The official OPML 2.0 spec defining the outline, head, and body elements this viewer parses.
RSS 2.0 Specification
The RSS 2.0 standard for the feed subscriptions commonly listed inside OPML files.
MDN — XML Introduction
Background on XML syntax, since OPML is an XML-based markup format.

Related Tools

OPML to JSON

Convert your OPML outline into structured JSON for programmatic use.

RSS Viewer

Preview and read the RSS feeds referenced inside an OPML file.

XML Viewer

Inspect any XML document, including raw OPML, in a readable tree.

XML to JSON

Transform XML or OPML markup into a JSON object structure.

Frequently Asked Questions

What is OPML?: OPML (Outline Processor Markup Language) is an XML format for outlines, often used for RSS feed lists.
Is the OPML Viewer free?: Yes, this tool is completely free and works offline once loaded—no signup or account is required.
What can I open with the OPML viewer online?: You can open any valid .opml file or pasted OPML/XML, including feed-reader subscription exports and outline documents, and view their full node hierarchy as a tree.
Can I view an OPML file as a mind map?: The viewer renders OPML as an expandable, collapsible tree that mirrors the outline hierarchy, giving you a mind-map-style overview of how nodes and sub-nodes are nested.
Is my OPML file uploaded to a server?: No. All parsing happens locally in your browser, so your OPML data is never sent to any server and stays on your device.