Validate against a schema. Find the exact problem.
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Your data stays yours.
Default checks run in your browser. Server checks require permission.One workbench. Your complete XML workflow.XSD 1.0 & 1.1 · Schematron · Multi-file projects · Cloud versions · API & CLI
Explore all features ↓Load an example or add your own XML and schema, then run validation.
Start free, without an account. Add Pro for batches and cloud storage, or Team for a shared workspace.
Check XML syntax and XSD 1.0 locally. Choose XSD 1.1, Schematron XPath 1.0 or a second XSD 1.0 engine with upload permission. Compare both engines in one check.
Example: catch an invalid invoice date or a total that breaks a Schematron rule.
Open XSD files, a folder or ZIP. Resolve includes and imports, switch file tabs and see a dependency graph. Import public HTTPS schemas and dependencies as an explicit snapshot.
Save five local revisions and export project or ZIP backups. Pro and Team add cloud projects with up to 50 versions.
Format XML, search and replace text, jump to reported lines and read explanations alongside validation errors. Export the result as JSON.
Example: “Expected a value of at least 1; found 0” helps you identify the constraint that failed.
Generate a starting XML document and validate it before using it. Compare schema structure across saved local versions and explore file dependencies.
Structural comparisons show changes; they do not certify compatibility. Complex examples may need manual editing.
Validate multiple XML files in one run: up to 25 on Pro or 100 on Team. Review per-file results and export a JSON report.
XML documents can be up to 10 MB each. Optional server batches allow up to 10 files and follow API rate limits.
Use the HTTPS validation API, Python CLI or downloadable GitHub Actions starter to check XML in your development workflow.
Server checks require explicit upload consent. The public API is rate-limited and has no enterprise SLA.
XML syntax, formatting and local XSD 1.0 checks run on your device. Local project saves stay in this browser.
Server validation needs upload consent. Public schema import contacts remote hosts. Cloud saving uploads schemas when you choose Save; it does not save XML documents.
Clear limits: 10 MB per XML document · 1 MB per schema · 100 schemas / 10 MB per project · 20 files per public HTTPS import. Schematron uses XPath 1.0; DTDs and private-network imports are blocked.
Paste a document or open a UTF-8 file. Start with the included examples to see what valid and invalid data look like.
An XSD defines the elements, order and data types your XML should use. Just checking the syntax? Switch to XML syntax only.
See validation errors with line numbers where available. Correct your data, check again, and export a JSON result for your records.
Default XSD 1.0 validation and formatting run on your device with libxml2 and WebAssembly, up to 10 MB per XML document and 1 MB per schema. Local projects support 100 schemas and 10 MB total; save them on this device with five revisions or export a backup. Optional server modes support XSD 1.1, a second XSD 1.0 engine and ISO Schematron XPath 1.0, with up to 10 MB XML. They upload documents only after you select the consent checkbox. Request contents are not logged and temporary files are removed after processing. Pro and Team can also save complete schema projects and versions to their cloud workspace. Cloud saving uploads the schemas only when you choose to save. DTDs are blocked. Use the separate public HTTPS importer to fetch schema snapshots before validating. Read the processing details or use the API and CLI.
Keep checking individual files for free. Upgrade for batch validation, a saved schema library and a shared Team workspace.
Pro from US$19/month. Team from US$49/month.
Save two months with annual billing.
Start with a syntax check, validate a document against its XSD, or format XML so you can inspect its structure. These are separate checks: readable, well-formed XML can still contain values that do not match your schema.
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