Building an EmDash Site

EmDash is a CMS built on Astro. It stores schema in the database (not in code), serves content via live content collections, and provides a full admin UI at /_emdash/admin. Sites are standard Astro projects with the emdash integration.

Common Gotchas

These are the things that silently break sites. Know them before you start.

1. Image fields are objects, not strings. post.data.featured_image is { id, src, alt }. Writing <img src={post.data.featured_image} /> renders [object Object]. Use <Image image={post.data.featured_image} /> from "emdash/ui".

2. entry.id vs entry.data.id are different things. entry.id is the slug (use in URLs). entry.data.id is the database ULID (use for getEntryTerms, Comments, and other API calls that need the real ID). Mixing them up causes silent empty results.

3. Taxonomy names must match the seed exactly. If your seed defines "name": "category", you must query getTerm("category", slug) -- not "categories". Wrong name = empty results, no error.

4. Always pass cacheHint to Astro.cache.set(). Every query returns a cacheHint. Call Astro.cache.set(cacheHint) on every page that queries content, or cache invalidation won't work when editors publish changes.

5. No getStaticPaths for CMS content. EmDash content is dynamic. Pages must be server-rendered (output: "server" in astro.config.mjs).

File Structure

Every EmDash site has these key files:

my-site/
├── astro.config.mjs          # Astro config with emdash() integration
├── src/
│   ├── live.config.ts         # EmDash loader registration (boilerplate)
│   ├── pages/                 # Astro pages (all server-rendered)
│   ├── layouts/               # Layout components
│   └── components/            # Reusable components
├── seed/
│   └── seed.json              # Schema + demo content
├── emdash-env.d.ts          # Generated types (from `emdash types`)
└── package.json

Workflow

1. Configure the project

Read references/configuration.md for astro.config.mjs, live.config.ts, deployment targets (Node vs Cloudflare), and type generation.

2. Design the schema

Read references/schema-and-seed.md for collection definitions, field types, taxonomies, menus, widget areas, sections, bylines, and the complete seed file format.

3. Build the pages

Read references/querying-and-rendering.md for content queries, Portable Text rendering, the Image component, visual editing attributes, caching, and common page patterns (list, detail, taxonomy archive, RSS, search, 404).

4. Wire up site features

Read references/site-features.md for site settings, navigation menus, taxonomies, widget areas, search, SEO meta, comments, and page contributions.

5. Create the seed file

Write seed/seed.json with collections, fields, taxonomies, menus, widgets, and sample content.

6. Run and verify

npx emdash dev          # Start dev server (runs migrations + seeds, and generates types)

The admin UI is at http://localhost:4321/_emdash/admin.

Quick API Cheat Sheet

// Content (entries have .data.byline and .data.bylines eagerly loaded)
import { getEmDashCollection, getEmDashEntry } from "emdash";
const { entries, nextCursor, cacheHint } = await getEmDashCollection("posts", {
	limit: 10,
	cursor,
	orderBy: { published_at: "desc" },
});
const { entry: post, cacheHint } = await getEmDashEntry("posts", slug);

// Site features
import {
	getSiteSettings,
	getMenu,
	getTaxonomyTerms,
	getTerm,
	getEntryTerms,
	getEntriesByTerm,
	getWidgetArea,
	search,
	getSection,
	getSeoMeta,
} from "emdash";

// Bylines (standalone queries -- usually not needed since entries have bylines attached)
import { getByline, getBylineBySlug } from "emdash";

// UI components
import {
	PortableText,
	Image,
	Comments,
	CommentForm,
	WidgetArea,
	EmDashHead,
	EmDashBodyStart,
	EmDashBodyEnd,
} from "emdash/ui";
import LiveSearch from "emdash/ui/search";

// Page context (for plugin contributions)
import { createPublicPageContext } from "emdash/page";

Plugins

EmDash supports plugins for extending the CMS with hooks, storage, settings, admin UI, API routes, and custom Portable Text block types. Consider a plugin when you need to:

• React to content lifecycle events (e.g., send a notification on publish, sync to an external service)
• Add custom admin pages or dashboard widgets
• Add custom block types to the Portable Text editor (e.g., embedded maps, code playgrounds, CTAs)
• Provide a reusable service (e.g., analytics, forms, comments via a third-party provider)

Plugins are registered in astro.config.mjs:

emdash({
	database: sqlite({ url: "file:./data.db" }),
	storage: local({ directory: "./uploads", baseUrl: "/_emdash/api/media/file" }),
	plugins: [myPlugin()],
}),

To build a plugin, load the creating-plugins skill (in .agents/skills/creating-plugins/). It covers plugin anatomy, hooks, storage, admin UI, API routes, Portable Text blocks, capabilities, and the full definePlugin() API.

Reference Documents

File	Contents
references/configuration.md	Project setup, astro.config, live.config, deployment, types
references/schema-and-seed.md	Collections, fields, taxonomies, menus, widgets, seed format
references/querying-and-rendering.md	Content APIs, PortableText, Image, caching, page patterns
references/site-features.md	Settings, menus, widgets, search, SEO, comments, page contributions