XML Visual Editor

Multi-platform toolkit for advanced XSD schema-aware XML editing.

Preview Release (v0.4.1) — This extension is in active development. Features are functional but the API may change. Feedback and bug reports are welcome!

Features

Core Features

• Pretty-Print — Reformat XML with configurable indentation (2/4 spaces, tab, or editor setting)
• Linearize — Compact XML to a single line, removing unnecessary whitespace
• Strip Whitespace — Remove all non-significant whitespace from the document
• Tag Autoclose — Automatically insert </tag> when you type >
• Copy XML Path — Copy the XPath of the element at the cursor to the clipboard
• Copy XML Path with Predicates — Copy XPath with index-based predicates (e.g. /root/item[2])
• Context Menu — Right-click menu with formatting, validation, and navigation commands
• Select Current Element — Select the entire element (open tag through close tag) at the cursor
• Go to Matching Tag — Jump between opening and closing tags
• Expand Self-Closing Tag — Convert <tag/> to <tag></tag>

Schema-Aware Features

• Real-Time XSD Validation — Validates as you type (500ms debounce), on save, and on open; inline markers, gutter icons, and Problems panel integration
• Interactive Elements Panel — Content model tree with compositor badges (sequence/choice/all), cardinality display, instance state styling, insert buttons, and focus algorithm
• Interactive Attributes Panel — Editable form with enum dropdowns, fixed-value locks, required/optional indicators, add/remove buttons, and documentation tooltips
• Interactive Info Panel — Collapsible sections with type info, documentation, compositor context, instance state, and enumeration values
• Schema-Aware Completions — Context- and Scehma aware element, attribute name, attribute value, and text content completions with rich documentation popups and "Insert Required" mode
• Schema Management — Auto-detection from xsi:schemaLocation / xsi:noNamespaceSchemaLocation, HTTP/HTTPS downloading with recursive import/include resolution, persistent local caching, and manual loading via file picker

Schema-Aware Editing

When an XSD schema is loaded — either auto-detected from the document or loaded manually — the extension unlocks a full suite of schema-aware features. The C++ engine parses the schema and provides real-time content model information, validation, and completions as you edit. All schema-dependent panels and completions update live as you move the cursor.

Interactive Helper Panels

Three interactive sidebar panels provide contextual information and editing capabilities based on the cursor position in the XML document.

Elements Panel

Displays a content model tree for the element at the cursor. Shows allowed child elements with compositor structure (sequence, choice, all), cardinality constraints, and instance state. Use the insert buttons to add elements at the correct position. Filter, expand/collapse, and toggle documentation/type columns from the toolbar.

Attributes Panel

Displays an editable form for the attributes of the element at the cursor. Enum attributes show dropdown selectors, fixed attributes show a lock icon, and required attributes are clearly indicated. Add missing attributes or remove optional ones with a single click.

Info Panel

Displays detailed schema information for the element at the cursor. Includes collapsible sections for type information, documentation, compositor context, instance state, and enumeration values. Useful for understanding schema constraints without leaving the editor.

Schema-Aware Completions

Context and Schema-aware completions appear as you type inside XML elements and attributes. Element completions show the content model tree with compositor structure. Attribute name completions list allowed attributes with required/optional indicators. Attribute value completions offer enum values and documentation. The "Insert Required" mode recursively inserts all required children and attributes in one action.

Validation

Real-time XSD validation reports errors and warnings as you type. Validation runs automatically on open, on save, and while typing (with a configurable debounce delay). Results appear as inline squiggly underlines, gutter icons, and entries in the Problems panel with line/column positions and descriptive messages.

Formatting & Productivity

Format XML documents with Pretty-Print (configurable indentation), Linearize (compact single-line), or Strip Whitespace. Tag Autoclose inserts closing tags automatically. Copy the XPath of any element to the clipboard. Access all commands from the right-click context menu or the Command Palette.

Requirements

• Visual Studio Code 1.85.0 or higher
• No additional dependencies — the C++ engine binary is bundled with the extension

Extension Settings

Known Limitations

• Preview/Beta release — Features are stable but the extension is under active development. Feedback welcome!
• Platform support: Windows x64 fully supported. Linux and macOS binaries coming soon.
• Schema support: XSD (XML Schema 1.0) only. RelaxNG and DTD are not supported.
• No XML tree view / outline — Planned for a future release.
• No code actions / quick fixes for validation errors — Planned for a future release.

License

MIT License

Third-Party Notices

This extension uses pugixml and nlohmann/json, both under the MIT License. See THIRD_PARTY_LICENSES.md for full license texts.