# Light - Developer guide - [Light developer guide](https://light.magerex.nl/md/developer.md): What Light is, how a module plugs in, and the rules every module follows. - [Install Light](https://light.magerex.nl/md/developer/install.md): Install Light 0.4 in a Mage-OS or Magento Open Source shop from packages.disrex.nl, add Returns or rate tables, update, and what to check afterwards: the doctor, stock and locations, two-factor sign-in. - [Getting started](https://light.magerex.nl/md/developer/getting-started.md): A first Light app in about 15 minutes, as a bridge or built into your module, and the checklist before you ship. - [How Light fits together](https://light.magerex.nl/md/developer/architecture.md): The parts of Light, a request to a Light page, the three ways to plug in, and the public API, as diagrams. - [Built for Light](https://light.magerex.nl/md/developer/ux-guidelines.md): Six rules that keep Light calm when a merchant installs ten modules. - [Build with an AI assistant](https://light.magerex.nl/md/developer/ai-assistants.md): The Markdown of every page, prompts that work, and an AGENTS.md for your repository. - Recipes - [An app, its category and pins](https://light.magerex.nl/md/developer/recipes/app-and-pins.md): Give your module a good Apps row: a job name, an icon, a category, an entry page and a settings page. - [A settings page from your system.xml](https://light.magerex.nl/md/developer/recipes/settings-page.md): A Light settings page drawn from your own system.xml, with only the everyday fields in simple mode. - [A nav item with a counter](https://light.magerex.nl/md/developer/recipes/nav-counter.md): A nav item under the right section, and a counter that shows the same work everywhere. - [Fields on a Light editor](https://light.magerex.nl/md/developer/recipes/form-card.md): A card with your fields on a Light editor, checked on the server and in the browser. - [Light lists](https://light.magerex.nl/md/developer/recipes/index-table.md): Your records in a Light list, and your columns and bulk actions on another module's list. - [Your own list and detail pages](https://light.magerex.nl/md/developer/recipes/own-pages.md): Your own list page, detail page and JSON endpoints on the light route. - [Order and customer pages](https://light.magerex.nl/md/developer/recipes/order-and-customer-pages.md): Order actions, timeline lines, totals rows and cards on the order and customer pages. - [Your module's email and document](https://light.magerex.nl/md/developer/recipes/email-and-documents.md): Customer emails and PDF documents in the shop's look: the body-only contract, the classes, the two tokens, the documents, item_lines, document_sections and pick_locations pools, a client format, and what an agency can change. - [The advanced view, the route map and header actions](https://light.magerex.nl/md/developer/recipes/advanced-and-route-map.md): Send stock screens to your Light pages, link into the advanced view, and add header actions to other pages. - [Users and permissions](https://light.magerex.nl/md/developer/recipes/users-and-permissions.md): Put your ACL resources in a role area, so roles reach your screens. - [Changing Light for one shop](https://light.magerex.nl/md/developer/recipes/change-core.md): Relabel, remove or re-sort what Light or another module declares, for one shop. - [Home to-dos, setup steps and widgets](https://light.magerex.nl/md/developer/recipes/home.md): To-dos, setup steps, widgets and banners on Home. - [The command palette](https://light.magerex.nl/md/developer/recipes/palette.md): Destinations, actions and search groups in the command palette. - [Channels and store views](https://light.magerex.nl/md/developer/recipes/channels-and-store-views.md): Settings per channel and store view, and counters that follow the channel filter. - [Locations and pickup](https://light.magerex.nl/md/developer/recipes/locations-and-pickup.md): Reading a shop's locations, what simple mode means, and how Light keeps stock, shipments and pickup in Magento's own inventory. - [A brand package](https://light.magerex.nl/md/developer/recipes/branding-package.md): Your name, logo and default theme on Light, from one di.xml file. - [An admin theme module](https://light.magerex.nl/md/developer/recipes/theme-package.md): An admin theme as a module: tokens only, in light and dark. - [Hyvä code in a -hyva module](https://light.magerex.nl/md/developer/recipes/storefront-hyva.md): Hyvä storefront code in its own -hyva module, next to your Light glue. - [AI in your module](https://light.magerex.nl/md/developer/recipes/ai.md): Call an LLM from your module through disrex/module-ai, with a purpose of your own, inside the shop's AI limits. - Reference - [Extension targets](https://light.magerex.nl/md/developer/reference/extension-targets.md): Every pool, container, handle, form, JS module and event, generated by the doctor. - [API reference](https://light.magerex.nl/md/developer/reference/api.md): Every @api type with its members, generated by the doctor. - [Events, JS modules and #mrx-config keys](https://light.magerex.nl/md/developer/reference/events.md): The DOM events, server events, JS modules and #mrx-config keys that are contract. - [Packages and compatibility](https://light.magerex.nl/md/developer/reference/packages.md): Every Light package, which ones install on their own and which come as a set, what a shop may leave off, the bridges to other modules with their version ranges, and the platforms each release is checked on. - [Compatibility gate messages](https://light.magerex.nl/md/developer/reference/compatibility.md): Every message of the compatibility gate, with its cause and its fix. - [Glossary](https://light.magerex.nl/md/developer/reference/glossary.md): Light's words and what Magento calls them. - [Versioning](https://light.magerex.nl/md/developer/versioning.md): What the Light API promises, what a release may change, and how your module declares the versions it supports. - [Upgrading](https://light.magerex.nl/md/developer/upgrading.md): What to change in your module for the 0.1.0 beta, for 0.1.1, 0.1.3, 0.2.0, 0.3.0, 0.4.0 and 0.4.9, and later for 1.0.0. - [Changelog](https://light.magerex.nl/md/developer/changelog.md): What each Light API release added, changed and deprecated. - [Testing](https://light.magerex.nl/md/developer/testing.md): The guards, checks and tests that keep Light and your module honest, and how to run them. - [Troubleshooting](https://light.magerex.nl/md/developer/troubleshooting.md): Symptoms, causes and fixes, and one entry per doctor rule. - [Case study: disrex/module-request-an-account](https://light.magerex.nl/md/developer/case-study-request-an-account.md): How the first real module joined Light with no change to Light core or to the module. - **Design system** - [Design system](https://light.magerex.nl/md/ui-kit.md): Page layout, components, JS modules, forms and lists for your own Light pages. - [Admin themes](https://light.magerex.nl/md/themes.md): The theme contract: scoping, inheritance, dark schemes, fonts, every token and the contrast checklist.