# Overview URL: https://zerodev.ca/docs/prism/developer-documentation > How a Prism module is laid out, how it loads and what it can hook into. Everything Prism does at runtime comes from a module, including Core. Your own modules load the same way and get the same access to the database, API, dashboard, audit log and languages. For installing and running Prism, see the [Setup Guide](/docs/prism/setup). ## Layout Each folder in `modules/` is one module. Prism imports its `main.js` and loads everything under `src/` and `resources/` by folder. ```text modules/ example/ main.js resources/ config/ lang/ web/ pages/ src/ clocks/ events/ handlers/ models/ routes/ ``` | Folder | Files loaded | Base class | | ---------------------- | --------------------------------------------------- | ---------- | | `main.js` | The module | `Modules` | | `src/models/` | Every `*.js` | `Models` | | `src/handlers/` | Every `*.js` | `Handlers` | | `src/routes/` | Every `route.js`, at any depth | `Routes` | | `src/clocks/` | Every `*.js` | `Clocks` | | `src/events/` | Every `*.js` | `Events` | | `resources/config/` | Every `*.js` | `Configs` | | `resources/lang/` | `en/*.js` classes, plus a folder of JSON per locale | `Langs` | | `resources/web/pages/` | Every `page.js`, at any depth | `Pages` | Import every base class from `#prism/modules`. Each file exports one class. Code goes in `src/`, config and setup in `resources/`. ## Loading Prism loads modules in two passes. Core always goes first, then every other module after the modules it `requires`. 1. **Register.** Install any missing `dependencies.node` packages, then read configs, languages, models, routes and pages. 2. **Load.** Create the tables, start handlers, events and clocks, call `onStartup()` and mount routes. When Prism stops, it stops clocks, removes events and calls `onShutdown()` for each module in reverse order. A module that throws while loading is marked as failed and shown on the **Modules** page and the Overview. The others keep running. If Core fails, Prism stops. ## main.js ```js title="modules/example/main.js" import { Modules } from "#prism/modules"; export class Example extends Modules { constructor(prism) { super(prism, { name: "example", author: "Your Name", version: "1.0.0", description: "Does one thing well", icon: "box", requires: ["core"], dependencies: { node: ["nanoid"] } }); } permissions() { return [{ id: "example.view", label: "View examples" }, { id: "example.edit", label: "Edit examples" }]; } async onStartup() { this.prism.console.log(this.prism.console.levels.info, `${this.getName()} started.`); } } ``` | Key | Default | What it does | | ---------------------------------- | -------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | | `name` | Required | The module ID. Use the lowercase folder name. | | `displayName` | `name` | Fallback label. Translate the name with `module..name` instead. See [Languages](/docs/prism/developer-documentation/languages#dashboard-text). | | `author`, `version`, `description` | None | Shown on the **Modules** page. | | `icon` | `puzzle` | A [Lucide](https://lucide.dev/icons) icon name. | | `requires` | `[]` | Modules that must load first. Missing ones fail this module. | | `dependencies.node` | `[]` | npm packages Prism installs before loading the module. | ## Hooks Add any of these methods to your module class. | Method | Called | | ------------------------------ | ------------------------------------------------------------------------------------------------------- | | `onStartup()` | After the module loads. | | `onShutdown()` | Before it unloads. | | `permissions()` | When Prism lists permissions. Return `[{ id, label }]`. They show up when editing roles and API tokens. | | `fields(module, page)` | When another module's page is described. Return extra form fields for it. | | `decorate(module, page, rows)` | When another module's page lists or creates rows. Return the rows with your data added. | The Kora module uses `fields` and `decorate` to add a **Kora product** picker to Core's product form: ```js fields(module, page) { if (module !== "core" || page !== "products") return []; return [{ key: "kora_product", label: "Kora product", type: "reference", source: { module: "kora", endpoint: "/products", label: "name", value: "id" }, empty: "No products found" }]; } ``` Core also runs a customer's licenses through `decorate("core", "accountLicenses", licenses)` before `GET /api/v1/account/licenses` returns them. Each license has a `fields` array that the **My Licenses** card shows under the product. Push `{ key, label, value, copy }` entries onto it, where `label` is a translation key from your module's `common.json` and `copy` adds a copy button. Kora uses this to show the Kora license key issued for each purchase: ```js decorate(module, page, rows) { if (module !== "core" || page !== "accountLicenses") return rows; return rows.map(row => ({ ...row, fields: [...row.fields, { key: "kora_key", label: "account.licenses.field.kora_key", value: "KORA-XXXX", copy: true }] })); } ``` ## The prism Object Every class gets the running instance as `this.prism`. | Property | What it is | | --------------------- | ----------------------------------------------------------------------------------- | | `this.prism.database` | The database connection. `this.prism.database.sequelize` is the Sequelize instance. | | `this.prism.settings` | Values from the **Settings** and **Theme** pages. | | `this.prism.console` | The logger. | | `this.prism.audit` | The audit log. | | `this.prism.signer` | Signs and checks payloads with the response signing key. | | `this.prism.mail` | Sends email through the SMTP settings. | | `this.prism.storage` | Uploads to and signs links for the S3 bucket. | | `this.prism.events` | The event bus. See [Events](/docs/prism/developer-documentation/events). | | `this.prism.modules` | Every loaded module and its parts. | | `this.prism.api` | The API server and permission checks. | See [Utilities](/docs/prism/developer-documentation/utilities) for each one. ## Reaching Other Modules ```js this.prism.modules.models.get("core", "products"); this.prism.modules.handlers.get("core", "licenses"); this.prism.modules.config.values("kora", "kora"); this.prism.modules.lang.phrase("core", "messages", "not_found"); ``` `get` returns `null` when that module is not loaded. ## Addons Paid extras on the Prism license, such as **Watermark**, are checked with: ```js if (this.prism.hasAddon("Watermark")) return; ```