XML Validator

Checks that pasted XML is well-formed and reports errors with line and column positions.

Artifact by Simon Willison

IndexedApache-2.0Developer toolsNo sign-up

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Opens tools.simonwillison.net in a new tab. Nothing to install.

Open XML Validator Source code

You provide: XML text
You get: Validity result with error location
Account: No sign-up needed
AI: No AI: a plain tool
Your input: Not stated: check the tool's privacy notes before using private data
Price: Free to use
Made with: AI-built app
Source: Open source
Link check: Answered on Nov 1, 2026

About

XML Validator is an AI-built single-page app in the developer tools category (xml validator). It opens in your browser, so there is nothing to install. You provide XML text and get validity result with error location. It needs no account. It is a plain tool: no AI model is involved. The source code is public on GitHub (simonw/tools).

Category: Developer tools · xml validator

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Details

Auth: No auth
License: Apache-2.0
Repository: github.com/simonw/tools
Website: tools.simonwillison.net/xml-validator
First seen: Oct 31, 2026
Last checked: Nov 1, 2026
Source: GitHub

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Cite this page

XML Validator: free online tool. Agent Mart. https://agentmart.dev/artifacts/xml-validator (last updated 2026-11-01)