Online XSD Viewer

Read, understand and share XML Schemas in your browser — no install, no account, no upload that sticks around.

Open https://www.xsd-viewer.online and drop in an .xsd file. You get a tree, an interactive XMLSpy-style diagram and the syntax-highlighted source side by side, all linked to the same selection.

What you can do with it

• See the whole schema at a glance. The diagram lays elements out the way XMLSpy and Oxygen do — sequences, choices, cardinalities, expand/collapse, pan & zoom.
• Three synchronised views. Pick a node in the Tree, jump to the Diagram, or switch to Text and land on the same line in the source — the selection follows you across all three.
• Everything the schema actually says. Elements, attributes, simple and complex types, facets, restrictions, xs:annotation / xs:documentation, xs:appinfo, XML comments, and the original source file and line number for every declaration.
• Multi-file schemas. Drop a single .xsd, several .xsd files at once, or a .zip containing the main schema plus its xs:import / xs:include / xs:redefine targets — the viewer resolves them and treats the bundle as one model. When more than one schema could be the root, a picker lists them with the most likely main file pre-selected.
• Load from a URL. Paste any public http(s) link to an XSD and the viewer fetches it (with private-IP and SSRF protections enabled). GitHub, GitLab and Bitbucket browse links (…/blob/…) are rewritten to the raw file automatically.
• Fast search. Press Ctrl/⌘ + K and start typing — full-text across element, type and attribute names, their xs:documentation and comments, and enumeration values. Documentation hits show the matching excerpt.
• Navigate like an IDE. Breadcrumbs, Find Usages, deep-linkable URLs (every node has its own hash), and a type-filter to narrow the tree.
• Share what you see. The 🔗 Share button copies a link to the current selection. For schemas loaded from a URL or a FundsXML release the link carries the source (/url?src=…, /fundsxml?release=…&file=…), so it opens the same schema and node for anyone. XPath and qualified names have their own copy buttons.
• Open straight to an input. Each way of loading a schema has its own address, so you can bookmark or link the one you want: / (File / ZIP), /paste, /url and /fundsxml. Browser back/forward switches between them.
• Sample XML. Pick any element and generate a skeleton instance document — required content, first choice branch, first enumeration value — with an option to include everything optional and to show repeatable elements up to three times. Values are examples that fit the declared types and facets: element and attribute names suggest them (Currency → EUR, Email → an address), and dates and numbers vary from one occurrence to the next. Copy it, download it, or open it in the XML Viewer.
• Export. Diagram as PNG or SVG, the whole schema as standalone HTML documentation, or pretty-printed XML.
• Light, Dark, Desktop, Tablet, Mobile. The UI follows prefers-color-scheme and reflows down to phone widths.
• Handles real-world schemas. Tested up to ~50 MB with virtual scrolling and lazy diagram rendering.

ISO 20022 messages by name

The ISO 20022 tab (www.xsd-viewer.online/iso20022) lists more than 300 payment, cash-management, collateral and remittance messages — pain.001, camt.053, pacs.008 and the rest, every version — searchable by code, name or root element. One click loads the schema; links such as /iso20022?message=pain.001.001.12 open it directly.

Load FundsXML releases with one click

If you work with FundsXML, the viewer pulls the official releases straight from the fundsxml/schema GitHub repo. Open the Load schema screen, pick the FundsXML Releases tab — or go straight to www.xsd-viewer.online/fundsxml — and click the version you want. Every release back to the early 4.x line is one click away, including its xmldsig-core-schema.xsd companion.

Your data stays with you

• Your schemas are not stored. Uploads are parsed in memory and dropped from a short-lived cache; no file persistence, no third-party analytics. The public site records anonymous aggregate usage statistics (a daily rotating visitor hash — never the raw IP —, country, browser family, referrer, the schema's file name / URL / target namespace and size, parse duration and outcome). Schema files are never written anywhere. The one exception: if a generated sample XML fails its schema check, the generated document and a few XSD lines around the declarations at fault are recorded so the generator can be fixed. Details and the full column list: docs/USAGE_STATS.md. Self-hosted installs have this off unless USAGE_DB_URL is set.
• Feedback is optional and anonymous. The 💬 Feedback button stores your message (plus the page, the loaded schema's name and the error you were looking at, if any) in the same statistics database — never your IP. An email address is kept only if you type one in.
• No account, no login. Just open the site and drop a file.
• You can run it yourself. The whole app is a single Docker container — see docs/TECHNICAL.md for self-hosting.

Self-host with Docker

Keep schemas inside your network, or let colleagues use it without internet access:

docker run --rm -p 8080:8080 ghcr.io/karlkauc/online-xsd-viewer:latest

Then open http://localhost:8080. Configuration and Cloud Run deployment: docs/TECHNICAL.md.

Embed a diagram or add a badge

Show an interactive diagram of a public schema on your own documentation site, or put an "Open in XSD Viewer" badge into a repository that publishes XSDs: www.xsd-viewer.online/features/badge.

No warranty

This tool is offered free of charge and without any warranty. The visualisation is a best-effort rendering of your schema; it is not a certified validator. Do not rely on it as the single source of truth for regulatory, contractual or production decisions — always verify against the authoritative schema and an established validator. Use is at your own risk.

Found a bug? Missing a feature?

Use the 💬 Feedback button in the app, or open an issue on GitHub (the GitHub button in the header and the ℹ️ About dialog link there too) — bug reports, reproduction steps and feature requests are all welcome:

➡️ https://github.com/karlkauc/xsd-online-viewer/issues

Have an XML document rather than a schema? The sister project XML Viewer shows the document as a tree and diagram and validates it against any XSD. It is linked from the header (XML Viewer ↗), the upload page and the About dialog; if you upload an XML document by mistake, the error message points there as well.

Need more than a viewer? FreeXmlToolkit

FreeXmlToolkit is the free desktop XML workstation by the same author (Apache 2.0; Windows, macOS, Linux): a schema-aware XML editor with IntelliSense and grid view, XSD documentation and profiled sample-data generation, Schematron business rules, XSLT and XProc, XML signatures and PDF output — all offline. The viewer links to it where the browser reaches its limits (sample XML, validation, documentation).

Technical details, self-hosting & development

Configuration, hardening, env vars, Cloud Run deployment, the architecture diagram and the dev-setup steps live in docs/TECHNICAL.md.

Author

Built and maintained by Karl Kauc — github.com/karlkauc.

License

MIT — see LICENSE and NOTICE.