Unsupported input
The tool may reject input that does not match the expected content, structure, or file type.
Fix: Confirm the tool input requirements and paste the correct type of data.
OPML Viewer
View OPML (Outline Processor Markup Language) files
OPML Preview
Inspect imported subscription outlines with a visible structure panel.
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What is OPML Viewer
Last reviewed:
OPML (Outline Processor Markup Language) is an XML format for outlines and, most commonly, for exchanging lists of RSS feed subscriptions.
OPML Viewer is an online tool that helps you view OPML.
It opens OPML in a focused browser workspace so you can inspect structure, navigate large documents, and copy fragments cleanly.
Why use it
- Work through OPML faster with a focused browser-based workflow.
- Review OPML input and output without switching between extra tools.
- Catch OPML issues earlier while the data or content is still in front of you.
- Keep OPML results easy to copy back into your project or process.
Example (before/after)
OPML input
Start with the OPML input you want to process in OPML Viewer.
OPML output
Get a OPML result from OPML Viewer that is ready to review, copy, and reuse in the next step of your workflow.
Common errors
Incomplete values
Missing fields or partial content can block processing or produce weak results.
Fix: Provide the full required input before running the tool.
Copying placeholder content
Sample or placeholder values can lead to output that looks valid but is not ready for real use.
Fix: Replace placeholders with your actual values before relying on the result.
FAQ
Does OPML Viewer work offline after the page loads?
Most of the processing is client-side, so once the page has loaded you can keep using OPML Viewer even if your connection drops — unless the tool explicitly hits a backend API for data it can't compute locally.
What does OPML Viewer do?
View OPML (Outline Processor Markup Language) files. Use it when you need a faster browser-based way to view OPML.
Is OPML Viewer free to use?
Yes. OPML Viewer is a free browser-based tool — no sign-up, no watermark, no rate limits for typical developer workflows.
Does OPML Viewer send my data to a server?
Almost all of the processing runs client-side in your browser, so pasted input stays on your device unless the tool explicitly calls an external API.
What input can I paste into OPML Viewer?
Paste the data type the tool is built for — plain text, code, or a structured payload — into the input panel. The tool processes it as you type.
Related tools
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