[Skip to content](#main-content) [![Jx Suite](/favicon.svg) Suite](/)Search⌘KESC Jump to [Install Jx Studio](/docs/start/install)[Build your first project](/docs/start/first-project)[Document format](/docs/framework/concepts/documents)[Formula catalog](/docs/framework/reference/formulas) ↵ select↑↓ navigateesc close [Studio](/studio)[Framework](/framework)[Templates](/templates)[Compare](/compare)[Docs](/docs/start/first-project)[GitHub](https://github.com/jxsuite/jx)[Download](/download) ✕ [Studio](/studio)[Framework](/framework)[Templates](/templates)[Compare](/compare)[Docs](/docs/start/first-project)[GitHub](https://github.com/jxsuite/jx) Color scheme [Download](/download) ☰ Docs menu Start here[Overview](/docs/start/)Get started[Install Jx Studio](/docs/start/install/)[Your first project](/docs/start/first-project/)[A tour of Jx Studio](/docs/start/studio-tour/)Tutorials[Tutorial: interactive component](/docs/start/first-component/)[Tutorial: blog with 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languages](/docs/framework/site/i18n/)[Images](/docs/framework/site/images/)[Redirects](/docs/framework/site/redirects/)[Feeds](/docs/framework/site/feeds/)[Site search](/docs/framework/site/search/)[Build output and adapters](/docs/framework/site/deployment/)How compilation works[Overview](/docs/framework/build/)[The dev server](/docs/framework/build/dev-server/)[CLI commands](/docs/framework/build/cli/)Working with agents[Overview](/docs/framework/agents/)[Authoring rules for agents](/docs/framework/agents/authoring-rules/)[Machine-readable docs](/docs/framework/agents/machine-readable/)Reference[Overview](/docs/framework/reference/)[Formula catalog](/docs/framework/reference/formulas/)[Operator reference](/docs/framework/reference/operators/)Extending[Overview](/docs/extending/)Extensions[Extension anatomy](/docs/extending/extensions/anatomy/)[Schema composition](/docs/extending/extensions/schema-composition/)[Custom classes](/docs/extending/extensions/classes/)[Custom formats](/docs/extending/extensions/formats/)[Capability methods](/docs/extending/extensions/capabilities/)[Project sections](/docs/extending/extensions/project-sections/)[Server mounts](/docs/extending/extensions/server/)[Connectors](/docs/extending/extensions/connectors/)[Search indexes](/docs/extending/extensions/search/)[Security and secrets](/docs/extending/extensions/security/)[Tutorial: a TOML format](/docs/extending/extensions/tutorial-toml-format/)[Tutorial: a guestbook](/docs/extending/extensions/tutorial-guestbook/)[First-party extensions](/docs/extending/extensions/first-party/)Embedding[Overview](/docs/extending/embedding/)[Hosting the Studio assets](/docs/extending/embedding/hosting/)[Writing a platform adapter](/docs/extending/embedding/platform-adapter/)[The backend protocol](/docs/extending/embedding/backend-protocol/)[Dev server internals](/docs/extending/embedding/dev-server/)[Embedding the runtime in your app](/docs/extending/embedding/runtime-host/)[Writing assistant tools](/docs/extending/embedding/assistant-harness/)UI kit[The Jx UI kit](/docs/extending/ui-kit/)Reference[Protocol routes](/docs/extending/reference/studio-routes/)[Implementation status](/docs/extending/reference/implementation-status/)[Spec changelog](/docs/extending/reference/spec-changelog/)[Standards alignment](/docs/extending/reference/standards/)Contributing[Working in the monorepo](/docs/extending/contributing/monorepo/)[Contributing to these docs](/docs/extending/contributing/docs/)[AI assistant evals](/docs/extending/contributing/ai-evals/) # Extension anatomy Jx documents are JSON. Everything beyond plain JSON enters the system through **extension packages**: Markdown content, dynamic data tables, authentication, whatever you build next. The unit of admission is an npm package (or a local directory) shipping a `jx-extension.json` manifest; a project opts in with one line in `project.json`. The first-party extensions (`@jxsuite/parser`, `@jxsuite/connector`, `@jxsuite/auth`) use only these public hooks, so anything they do, your extension can do. An extension contributes up to four kinds of things, all declared in JSON before any code runs: - **Classes**: `.class.json` descriptors that become `$prototype`-visible names ([Custom classes](/docs/extending/extensions/classes)). - **Formats**: file-extension handling for parsing, saving, and content loading ([Custom formats](/docs/extending/extensions/formats)). - **Project sections**: top-level `project.json` keys with data loading and Studio settings UI ([Project sections and settings](/docs/extending/extensions/project-sections)). - **Schema fragments**: JSON Schema documents composed into the project's effective schema ([Schema composition](/docs/extending/extensions/schema-composition)). ## Package layout The parser is the reference extension, and its layout is the template: ```text extensions/ parser/ # @jxsuite/parser — content collections, markdown, CSV package.json # "jx": "./jx-extension.json"; exports manifest, schemas, classes jx-extension.json schemas/ project.fragment.schema.json document.fragment.schema.json src/ Markdown.class.json # class descriptors (admission blocks + capability methods) markdown.ts # implementations connector/ # @jxsuite/connector — connections + dynamic data tables auth/ # @jxsuite/auth — Better Auth sessions and permissions ``` Three files matter to hosts: `package.json` names the manifest in its `"jx"` field, the manifest enumerates classes and schema fragments, and each `.class.json` descriptor declares what its class actually does. Implementation modules (`markdown.ts`) are imported only when a host invokes a declared capability. Discovery is JSON all the way down. Publish the manifest, descriptors, and fragments: they must appear in `package.json`'s `files` and `exports` so hosts can resolve `/jx-extension.json` through the exports map. ## Dependency rules In the Jx monorepo, `packages/*` is **core** and `extensions/*` is **extensions**. The arrow between them points one way: - Extensions may depend on core packages and on each other. `@jxsuite/auth` depends on `@jxsuite/connector` for its database connection. - Core packages may **never** list an extension in `dependencies`, `peerDependencies`, or `optionalDependencies`, and may never import `@jxsuite/` from `src/`. `devDependencies` are permitted for test fixtures only. CI enforces this in `scripts/check-dep-rules.ts`. - Bundling carve-outs are explicit and allowlisted with rationale: `packages/desktop` (an offline app shipped as installers, never published to npm) bundles the first-party extensions. Carve-outs live at the app layer, never in core libraries. Third-party extensions live outside the monorepo, but the same shape applies: depend on `@jxsuite/*` core packages and other extensions freely; nothing in core will ever know your package exists. ## Declaring extensions in a project A project enables extensions in `project.json`: ```json shiki ``` - Entries are bare package names or relative paths (for local, unpublished extensions). Package names resolve **project-first**: the project's own `node_modules`, then the host's. Projects own their extension dependencies, so a scaffolded project lists `@jxsuite/parser` in its `package.json`. - `imports` keeps its original, reduced job: mapping `$prototype` names to **project-local** class files. It does not register formats or extensions. - **Name visibility**: the manifest's class keys become `$prototype`-visible names. On a collision, a project-local `imports` entry wins over a manifest class; two extensions exporting the same class name is a registry error. Rename via a local wrapper class to disambiguate. - **No implicit defaults.** A project with no `extensions` supports only `.json` documents and core state prototypes. ## Section keys Extensions contribute top-level `project.json` keys ("sections"): `content` (parser), `connections` and `data` (connector), `auth` (auth). By convention section keys are single words, and the key is used verbatim as: - the property name in `project.json`, - the key under `_project` in resolved scope (`config._project.content`), - the wire-path segment where applicable. Two extensions claiming the same section key is a registry error. See [Project sections and settings](/docs/extending/extensions/project-sections) for what owning a section means. ## The `jx-extension.json` manifest The manifest lives at the package root, referenced by `"jx": "./jx-extension.json"` in `package.json`. The parser's real manifest, in full: ```json shiki ``` | Key | Type | Meaning | | ------------- | ------------------------ | -------------------------------------------------------------------------------------------------------------- | | `name` | `string` (required) | Package name; must match `package.json`. | | `title` | `string` | Human-readable name for Studio surfaces. | | `description` | `string` | One-line description. | | `classes` | `Record` | `$prototype`-visible name → class descriptor path, relative to the manifest. | | `schemas` | `object` | Schema fragments this package contributes: `project` (project.json sections), `document` (document positions). | The manifest is pure data, validated by the generated `extension-manifest.schema.json` from `@jxsuite/schema`. It enumerates; it does not define behavior. That lives in the class descriptors it points to. Note The registry implementing manifest discovery is `buildExtensionRegistry()` in `@jxsuite/schema/extension-registry` , with injected I/O so the identical logic serves node and browser hosts. It also enforces the conflict rules: duplicate class names, duplicate section keys, and overlapping server mounts all fail the registry build with a named error. ## Related - [Schema composition](/docs/extending/extensions/schema-composition): what the `schemas` fragments contribute - [Custom classes](/docs/extending/extensions/classes): the descriptors the `classes` map points to - [Tutorial: a TOML format extension](/docs/extending/extensions/tutorial-toml-format): a complete third-party package, end to end - [First-party extensions](/docs/extending/extensions/first-party): what parser, connector, and auth each provide ✕ Start here[Overview](/docs/start/)Get started[Install Jx Studio](/docs/start/install/)[Your first project](/docs/start/first-project/)[A tour of Jx Studio](/docs/start/studio-tour/)Tutorials[Tutorial: interactive component](/docs/start/first-component/)[Tutorial: blog with collections](/docs/start/first-collection/)[Video tutorials](/docs/start/videos/)Coming from another tool[Coming from WordPress](/docs/start/coming-from-wordpress/)[Coming from Webflow or Framer](/docs/start/coming-from-webflow/)[Coming from Wix or Squarespace](/docs/start/coming-from-wix/)[Coming from Lovable or Builder.io](/docs/start/coming-from-ai-builders/)Studio[Overview](/docs/studio/)[The desktop app](/docs/studio/desktop/)The workspace[Overview](/docs/studio/interface/)[Welcome screen](/docs/studio/interface/welcome-screen/)[Editors and views](/docs/studio/interface/modes/)[The canvas](/docs/studio/interface/canvas/)[Documents and panes](/docs/studio/interface/tabs/)[Quick Access](/docs/studio/interface/quick-access/)[Keyboard shortcuts](/docs/studio/interface/shortcuts/)[Preferences](/docs/studio/interface/preferences/)[Languages](/docs/studio/interface/languages/)[Problems and progress](/docs/studio/interface/problems-and-progress/)[Commands](/docs/studio/interface/commands/)Projects[Overview](/docs/studio/projects/)[Create a project](/docs/studio/projects/create/)[Pages, layouts, components](/docs/studio/projects/pages-layouts-components/)[The Content workspace](/docs/studio/projects/browse/)[Starter templates](/docs/studio/projects/starters/)[Media](/docs/studio/projects/media/)[Content types](/docs/studio/projects/content-types/)[Project settings](/docs/studio/projects/settings/)[Dependencies and imports](/docs/studio/projects/dependencies/)Edit mode[Overview](/docs/studio/editing/)[Writing and formatting](/docs/studio/editing/writing/)[Slash commands](/docs/studio/editing/slash-commands/)[Frontmatter and metadata](/docs/studio/editing/frontmatter/)[Grid mode](/docs/studio/editing/grid/)Design mode[Overview](/docs/studio/design/)[Outline](/docs/studio/design/layers/)[Insert](/docs/studio/design/elements/)[Content tab](/docs/studio/design/properties/)[Style inspector](/docs/studio/design/style-inspector/)[Breakpoints](/docs/studio/design/breakpoints/)[States and selectors](/docs/studio/design/states-and-selectors/)[Design tokens](/docs/studio/design/tokens/)[Project Styles](/docs/studio/design/stylebook/)[Working with components](/docs/studio/design/components/)[Repeaters](/docs/studio/design/repeaters/)Logic[Overview](/docs/studio/logic/)[Formulas and expressions](/docs/studio/logic/formulas/)[Formula workspace](/docs/studio/logic/formula-workspace/)[Statements](/docs/studio/logic/statements/)[Logic tab](/docs/studio/logic/events/)[Data](/docs/studio/logic/data/)[Data sources](/docs/studio/logic/data-sources/)[Code editing](/docs/studio/logic/code/)Databases[Overview](/docs/studio/data/)[Connections](/docs/studio/data/connections/)[Data tables](/docs/studio/data/tables/)[Data grid](/docs/studio/data/grid/)[Auth and secrets](/docs/studio/data/auth-and-secrets/)AI assistant[Overview](/docs/studio/ai/)[The AI assistant](/docs/studio/ai/chat/)[Document assistant](/docs/studio/ai/document-assistant/)Publish[Overview](/docs/studio/publish/)[Source control](/docs/studio/publish/source-control/)[GitHub](/docs/studio/publish/github/)[Cloudflare Pages](/docs/studio/publish/cloudflare/)[Other hosts](/docs/studio/publish/other-hosts/)[Redirects](/docs/studio/publish/redirects/)[Real-time collaboration](/docs/studio/publish/collaboration/)Framework[Overview](/docs/framework/)Concepts[Documents](/docs/framework/concepts/documents/)[Elements](/docs/framework/concepts/elements/)[Components](/docs/framework/concepts/components/)[Props and scope](/docs/framework/concepts/props-and-scope/)[State](/docs/framework/concepts/state/)[Reactivity](/docs/framework/concepts/reactivity/)[References](/docs/framework/concepts/references/)[Expressions](/docs/framework/concepts/expressions/)[Statements](/docs/framework/concepts/statements/)[Functions and sidecars](/docs/framework/concepts/functions/)[Styling](/docs/framework/concepts/styling/)[Color schemes](/docs/framework/concepts/color-schemes/)[Popovers and overlays](/docs/framework/concepts/overlays/)[Accessibility](/docs/framework/concepts/accessibility/)[Lists and iteration](/docs/framework/concepts/lists/)[Data prototypes](/docs/framework/concepts/data-prototypes/)[Timing](/docs/framework/concepts/timing/)[Dynamic switching](/docs/framework/concepts/switching/)[Security](/docs/framework/concepts/security/)Site architecture[Overview](/docs/framework/site/)[project.json](/docs/framework/site/project-json/)[Routing](/docs/framework/site/routing/)[Layouts](/docs/framework/site/layouts/)[Content collections](/docs/framework/site/content-collections/)[Jx Markdown](/docs/framework/site/jx-markdown/)[Obsidian vault as content](/docs/framework/site/obsidian-vault/)[Relationships](/docs/framework/site/relationships/)[SEO and metadata](/docs/framework/site/seo/)[Locales and languages](/docs/framework/site/i18n/)[Images](/docs/framework/site/images/)[Redirects](/docs/framework/site/redirects/)[Feeds](/docs/framework/site/feeds/)[Site search](/docs/framework/site/search/)[Build output and adapters](/docs/framework/site/deployment/)How compilation works[Overview](/docs/framework/build/)[The dev server](/docs/framework/build/dev-server/)[CLI commands](/docs/framework/build/cli/)Working with agents[Overview](/docs/framework/agents/)[Authoring rules for agents](/docs/framework/agents/authoring-rules/)[Machine-readable docs](/docs/framework/agents/machine-readable/)Reference[Overview](/docs/framework/reference/)[Formula catalog](/docs/framework/reference/formulas/)[Operator reference](/docs/framework/reference/operators/)Extending[Overview](/docs/extending/)Extensions[Extension anatomy](/docs/extending/extensions/anatomy/)[Schema composition](/docs/extending/extensions/schema-composition/)[Custom classes](/docs/extending/extensions/classes/)[Custom formats](/docs/extending/extensions/formats/)[Capability methods](/docs/extending/extensions/capabilities/)[Project sections](/docs/extending/extensions/project-sections/)[Server mounts](/docs/extending/extensions/server/)[Connectors](/docs/extending/extensions/connectors/)[Search indexes](/docs/extending/extensions/search/)[Security and secrets](/docs/extending/extensions/security/)[Tutorial: a TOML format](/docs/extending/extensions/tutorial-toml-format/)[Tutorial: a guestbook](/docs/extending/extensions/tutorial-guestbook/)[First-party extensions](/docs/extending/extensions/first-party/)Embedding[Overview](/docs/extending/embedding/)[Hosting the Studio assets](/docs/extending/embedding/hosting/)[Writing a platform adapter](/docs/extending/embedding/platform-adapter/)[The backend protocol](/docs/extending/embedding/backend-protocol/)[Dev server internals](/docs/extending/embedding/dev-server/)[Embedding the runtime in your app](/docs/extending/embedding/runtime-host/)[Writing assistant tools](/docs/extending/embedding/assistant-harness/)UI kit[The Jx UI kit](/docs/extending/ui-kit/)Reference[Protocol routes](/docs/extending/reference/studio-routes/)[Implementation status](/docs/extending/reference/implementation-status/)[Spec changelog](/docs/extending/reference/spec-changelog/)[Standards alignment](/docs/extending/reference/standards/)Contributing[Working in the monorepo](/docs/extending/contributing/monorepo/)[Contributing to these docs](/docs/extending/contributing/docs/)[AI assistant evals](/docs/extending/contributing/ai-evals/) [![Jx Suite](/favicon.svg) Suite](/)The visual IDE for the web. Build any website, save it as plain files, own it forever. MIT licensed. Product [Studio](/studio)[Download](/download)[Templates](/templates)[Features](/features)[Compare](/compare)[Jx Cloud (soon)](/cloud) Developers [Docs](/docs/start/first-project)[Framework](/framework)[Get Studio](/docs/start/install)[Spec](/docs/framework)[GitHub](https://github.com/jxsuite/jx) Project [MIT License](https://github.com/jxsuite/jx/blob/main/LICENSE)[Releases](https://github.com/jxsuite/jx/releases/latest)[Privacy](/privacy)[Terms](/terms)[Support](/support) Built with Jx Suite. © 2026 Avunu LLC. Open source under the MIT License.