← Toolsjsonui-helper (VS Code)Syntax highlighting + schema-aware completion + preview-on-save for Layout JSON and screen_spec.json. One install away from a JsonUI-native editing experience. Publisher jsonui, extension ID jsonui.jsonui-helper — the Marketplace listing is the source of truth for the current version.~5 min read
What it doesThree small things, all aimed at keeping you inside the editor: color-highlights Layout JSON so @{bindings} and styles jump out; autocompletes attributes against the same schema the MCP server serves; re-renders the screen in a sidebar pane whenever you save. Nothing exotic — just boring, fast feedback while you author.
InstallFrom the VS Code Marketplace. One command from the terminal, or search the Extensions sidebar.
shell
# Install from Marketplacecode --install-extension jsonui.jsonui-helper # Or search 'jsonui-helper' in the Extensions sidebar# Publisher: jsonui | ID: jsonui.jsonui-helper | v0.1.0FeaturesSyntax highlighting for Layout JSON and screen_spec.json with binding-aware tokenization. Autocomplete driven by attribute_definitions.json — the same source the MCP server reads, so completions stay in sync with the runtime. Preview-on-save renders the current file in a WebView pane using a minimal rjui runtime. Quick-action to validate the current spec via doc_validate_spec. Schema-diagnostic squigglies highlight invalid attribute values before you save.
Known limitsThe extension is editor intelligence only — completion, hover, navigation, diagnostics, and insert commands. There is no rendered preview of a layout in the sidebar on any platform; use hot reload (`jui hotload`) or the platform build for that. Multi-root workspaces pick up the first workspace's jui.config.json; multi-project workspaces need to be opened one at a time. The old swiftjsonui-helper extension is discontinued; jsonui-helper is its successor and has schema coverage for all three platforms.
Keep reading
jsonui-cliThe CLI that powers the commands the extension invokes under the hood./tools/cli
InstallationOne-liner that sets up the CLI, MCP, and agent pack — not the VS Code extension./learn/installation