# XSDHub > Browser-based XML syntax checking, XSD 1.0 validation with local imports and includes and XML formatting, with practical guides and a public read-only documentation MCP server. Founder: Daniel Haket. Support: support@xsdhub.com. Default XML processing is local; optional server modes upload documents with explicit consent. Maximum 10 MB XML and 1 MB per schema, UTF-8 only. Local XSD imports/includes are supported through file, folder or ZIP loading, up to 100 schemas and 10 MB total. Server mode supports XSD 1.1 and Schematron XPath 1.0, with 10 MB XML and explicit consent. No DTDs or implicit network fetching. Public HTTPS schemas can be imported separately, and Pro/Team projects can be saved in the cloud with version history. Projects can be saved locally with five revisions and exported. Paddle handles subscription checkout; check the current pricing page before describing availability. The affiliate pilot accepts applications through FirstPromoter; manual approval and activated referral links are required. MCP provides documentation, not account operations. A separate HTTPS validation API and CLI are documented at /developers. ## Tools and connection - [Validate XML online. Keep your data local.](https://xsdhub.com/xml-validator.md): Validate XML syntax in your browser, find malformed tags and read errors with line numbers. Free, no document uploads. UTF-8 XML files up to 10 MB. - [Validate XML against XSD. Find the mismatch.](https://xsdhub.com/xsd-validator.md): Check XML against an XSD 1.0 schema online. Find missing fields, wrong element order and invalid data types, privately in your browser. Free to use. - [Format your XML. See the structure.](https://xsdhub.com/xml-formatter.md): Format and pretty print XML in your browser. Make nested elements easier to read, preserve mixed content and copy the result. No XML uploads required. - [XML validation API and CLI](https://xsdhub.com/developers.md): Automate XSD 1.0, XSD 1.1 and Schematron XPath 1.0 checks with explicit server-processing consent. - [XSDHub for AI assistants](https://xsdhub.com/ai.md): Public MCP connection and machine-readable documentation. ## Guides - [XML vs XSD: what each check tells you](https://xsdhub.com/learn/xml-vs-xsd.md): Understand the difference between XML syntax and XSD validation, with a working quantity example, namespace guidance and a practical debugging sequence. - [Fix XML validation errors at the right layer](https://xsdhub.com/learn/fix-xml-validation-errors.md): Debug malformed XML, missing child elements, invalid numeric values and namespace mismatches. Practical examples explain what to inspect before changing data. - [How to validate XML against XSD, step by step](https://xsdhub.com/learn/validate-xml-against-xsd.md): Use a complete XML and XSD example to check required attributes, numbers and element order. Learn how to read a failed result and retest the fix. - [Fix XML namespace mismatches without guessing](https://xsdhub.com/learn/xml-namespaces-explained.md): Understand xmlns, prefixes, targetNamespace and elementFormDefault with a complete XML/XSD pair and a practical namespace debugging checklist. - [Escape XML characters without double-encoding data](https://xsdhub.com/learn/xml-escape-characters.md): Fix unescaped ampersands and less-than signs, choose attribute quotes correctly, and understand when CDATA helps. Includes valid and invalid XML examples. - [Use minOccurs and maxOccurs to control repetition](https://xsdhub.com/learn/xsd-minoccurs-maxoccurs.md): See how XSD occurrence limits affect missing, optional and repeated elements. Test a complete basket schema and learn why an empty element is not an absent one. - [Read XSD data-type errors with concrete examples](https://xsdhub.com/learn/xsd-data-types.md): Check valid lexical forms for common XSD types with a complete schema. Fix decimal commas, boolean labels and date formats without changing the intended value. - [Choose between xs:sequence and xs:choice](https://xsdhub.com/learn/xsd-sequence-vs-choice.md): Learn why XML child order can fail validation and how xs:choice expresses alternatives. Includes a complete contact schema and examples of both failure modes. - [Fix an XML opening and ending tag mismatch](https://xsdhub.com/learn/xml-tag-mismatch.md): Find mismatched XML tags with a tested broken example, corrected XML and an in-browser validator. Check nesting, spelling and case. - [Fix “This element is not expected” in XSD validation](https://xsdhub.com/learn/xsd-element-not-expected.md): Debug unexpected XML elements by checking sequence, namespace, spelling and occurrence rules. Try a complete failing and corrected XML/XSD pair. - [Fix an invalid xs:date value in XML](https://xsdhub.com/learn/xsd-invalid-date.md): Replace ambiguous date formats with valid xs:date values. Test a complete XML/XSD example and check calendar dates, time zones and empty values. ## About and plans - [XSDHub Affiliate Pilot — Earn 30% for 12 Months](https://xsdhub.com/partners.md): Apply for the XSDHub affiliate pilot. 30% commission on eligible subscription revenue for 12 months, with manual approval and clear product limits. - [XSDHub Affiliate Pilot — Terms](https://xsdhub.com/affiliate-terms.md): Eligibility, attribution, commission, payout and promotion rules for the XSDHub affiliate pilot. Manual approval is required. - [About XSDHub and Daniel Haket](https://xsdhub.com/about.md): Founder, development process, scope and corrections. - [XSDHub plans](https://xsdhub.com/pricing.md): Current plan descriptions and subscription availability. Prices exclude applicable tax. - [Terms of Service](https://xsdhub.com/terms.md): Terms for using XSDHub XML tools, accounts, subscriptions and shared schema libraries. - [Privacy Policy](https://xsdhub.com/privacy.md): How XSDHub handles local XML processing, account information, saved schemas, server logs and privacy requests. - [Refund Policy](https://xsdhub.com/refunds.md): How to cancel an XSDHub subscription, request a refund or exercise applicable consumer withdrawal rights. ## Optional - [Full public text](https://xsdhub.com/llms-full.txt): Combined Markdown content with canonical source URLs. - [Sitemap](https://xsdhub.com/sitemap.xml): Public HTML URLs. - [Robots policy](https://xsdhub.com/robots.txt): Crawler access rules.