Web
XML Validator
Validate XML syntax with detailed error messages. Instantly find missing tags, unquoted attributes and malformed structure.
Paste an XML document to validate.
Why use our XML Validator?
100% private
Everything runs in your browser. Your data never leaves your device — safe for production payloads.
Instant results
No round trips, no rate limits, no login. Format, validate and inspect megabytes of JSON in milliseconds.
Standards-first
Follows RFC 8259 / ECMA-404 exactly. Reports errors with precise line and column diagnostics.
Related developer tools
JSON Validator
Validate JSON syntax against RFC 8259 in real time. Precise line and column error reporting, 100% client-side.
OpenXML Formatter
Format, indent and validate XML documents. Preserves attributes, CDATA and comments — 100% in-browser.
OpenXML Parser
Parse XML into structured JSON with attributes, text nodes and namespaces preserved. Handy for legacy APIs.
OpenXML Pretty Print
Pretty-print XML with configurable indentation. Auto-validates against parse errors and shows precise line diagnostics.
OpenXML Viewer
Explore XML documents as an expandable tree. Inspect nodes, attributes and text — no upload needed.
OpenYAML Validator
Validate YAML syntax against the YAML 1.2 spec with precise error locations. Great for CI/CD config files.
OpenRelated reading
Deep-dive guides that pair well with the XML Validator.
Comparisons
JSON vs XML: which should you use?
Compare readability, verbosity, tooling, schema support and performance between JSON and XML in modern systems.
ReadDeveloper Tips
10 common JSON errors and how to fix them
Every JSON syntax error you'll ever see — trailing commas, unquoted keys, bad escapes — with a working repair strategy.
ReadTutorials
The complete JSON validation guide
How to validate JSON at every layer — parser, JSON Schema, and business logic — with practical examples.
Read