.yaml previewer - (yaml)

A standalone VS Code extension for a live, collapsible YAML tree and a JSON view. Supports .yaml, .yml, multiple YAML documents, nested collections, scalar values, and syntax error messages with parser line/column details. Changes appear after a short typing delay. Uses your VS Code theme and works offline, including untrusted workspaces.

Use

Install the .vsix using Extensions: Install from VSIX.... Open a YAML file and click the preview icon in the editor title, or run YAML: Open Preview to the Side. Shortcut: Ctrl+K V (macOS: Cmd+K V). You can also right-click a YAML file in Explorer.

Develop

Open this folder separately in VS Code, run npm install, then npm run build. Press F5 to launch an Extension Development Host. Open examples/sample.yaml in that window and run the preview command.

Run npm test for renderer checks and npm run package to build a VSIX.

Limits

Preview size is limited to 1 MB, tree depth to 30 levels, and tree nodes to 10,000 per document. YAML uses the parser's JSON schema (dates remain strings; custom executable tags are rejected). Circular aliases are marked in the tree; repeated aliases are represented by a placeholder in JSON. Comments and formatting are not included in the parsed preview. The preview refresh resets expanded nodes. No scripts run in the preview.