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Configuration Reference

EmDash is configured through two files: astro.config.mjs for the integration and src/live.config.ts for content collections.

Configure EmDash as an Astro integration in astro.config.mjs:

astro.config.mjs
import { defineConfig } from "astro/config";
import emdash, { local, s3 } from "emdash/astro";
import { sqlite, libsql } from "emdash/db";
export default defineConfig({
integrations: [
emdash({
database: sqlite({ url: "file:./data.db" }),
storage: local({
directory: "./uploads",
baseUrl: "/_emdash/api/media/file",
}),
plugins: [],
}),
],
});

Required. Database adapter configuration. Choose one adapter:

// SQLite (Node.js)
database: sqlite({ url: "file:./data.db" });
// PostgreSQL
database: postgres({ connectionString: process.env.DATABASE_URL });
// libSQL
database: libsql({
url: process.env.LIBSQL_DATABASE_URL,
authToken: process.env.LIBSQL_AUTH_TOKEN,
});
// Cloudflare D1 (import from @emdash-cms/cloudflare)
database: d1({ binding: "DB" });

See Database Options for details.

Optional. Controls runtime handling of EmDash’s internal database migrations. Omitting this option defaults to { runtime: "auto" }.

migrations: {
runtime: "check", // "auto" | "check" | "manual"
dev: "auto", // optional development override
}

auto checks and applies pending migrations, check returns 503 when migrations known to the running build are pending, and manual performs no runtime migration query. EMDASH_MIGRATIONS_MODE overrides the effective runtime mode. See Manage Core Database Migrations before adopting check or manual.

Required. Media storage adapter configuration. Choose one adapter:

// Local filesystem (development)
storage: local({
directory: "./uploads",
baseUrl: "/_emdash/api/media/file",
});
// R2 binding (Cloudflare Workers)
storage: r2({
binding: "MEDIA",
publicUrl: "https://pub-xxxx.r2.dev", // optional
});
// S3-compatible (any platform) — all fields from S3_* environment variables
storage: s3()
// Or with explicit values
storage: s3({
endpoint: "https://s3.amazonaws.com",
bucket: "my-bucket",
accessKeyId: process.env.S3_ACCESS_KEY_ID,
secretAccessKey: process.env.S3_SECRET_ACCESS_KEY,
region: "us-east-1", // optional, default: "auto"
publicUrl: "https://cdn.example.com", // optional
});

See Storage Options for details.

Optional. Caches content and configuration query results in a key/value store so reads are served without querying the database on every request. Disabled when omitted. Choose one adapter:

// Cloudflare KV (shared across all isolates)
import { kvCache } from "@emdash-cms/cloudflare";
objectCache: kvCache({ binding: "CACHE" });
// In-memory (Node.js / development)
import { memoryCache } from "emdash/astro";
objectCache: memoryCache();

See Object Cache for setup and options.

Optional. Registers an Astro middleware module outside the complete EmDash middleware stack. Because the integration registers it with Astro order: "pre", it also runs before middleware defined in src/middleware.ts. Use it for request gates or full-response caches that must avoid runtime and database initialization on a hit, or for response headers that depend on EmDash’s final HTML.

astro.config.mjs
emdash({
middleware: {
outer: "./src/outer-middleware.ts",
},
});

The execution order is:

  1. The outer middleware runs up to await next().
  2. EmDash initializes its runtime and database, then runs setup, authentication, and request-context middleware.
  3. The Astro route renders.
  4. EmDash applies response mutations, including visual-editing HTML and security/timing headers.
  5. next() resolves to the outer middleware with that final response.

Before calling next(), the middleware has the normal Astro request and platform execution context, but locals.emdash, locals.user, the database, and request-scoped EmDash state are unavailable. An early Response skips EmDash entirely, so it must include any security and cache headers it needs. After next() resolves, it is safe to finalize CSP nonces, cache the complete body, or set Content-Length. If the middleware changes the body, remove or recompute any existing Content-Length header.

The hook uses Astro’s middleware API on both Node and Cloudflare. This minimal Cloudflare Cache API example caches only anonymous HTML responses and returns hits before EmDash initialization:

src/outer-middleware.ts
import { waitUntil } from "cloudflare:workers";
import { defineMiddleware } from "astro:middleware";
export const onRequest = defineMiddleware(async ({ request }, next) => {
if (request.method !== "GET" || request.headers.has("cookie")) {
return next();
}
const cacheKey = new Request(request.url, { method: "GET" });
const cached = await caches.default.match(cacheKey);
if (cached) return cached;
const response = await next();
const isHtml = response.headers.get("content-type")?.includes("text/html");
const isPrivate = response.headers.get("cache-control")?.includes("no-store");
if (response.ok && isHtml && !isPrivate) {
waitUntil(caches.default.put(cacheKey, response.clone()));
}
return response;
});

On Node, use the same middleware shape with a Node-compatible cache such as Redis. Cache keys and bypass rules must include every request property that changes the rendered response.

Optional. Array of EmDash plugins. The following example registers one plugin:

import seoPlugin from "@emdash-cms/plugin-seo";
plugins: [seoPlugin()];

Optional. Admin UI font configuration.

By default, EmDash loads Noto Sans via the Astro Font API. Fonts are downloaded from Google at build time and self-hosted, so there are no runtime CDN requests. The base font covers Latin, Cyrillic, Greek, Devanagari, and Vietnamese scripts.

To add support for additional writing systems, pass script names. The following example adds Arabic and Japanese:

emdash({
fonts: {
scripts: ["arabic", "japanese"],
},
})

The available scripts are arabic, armenian, bengali, chinese-simplified, chinese-traditional, chinese-hongkong, devanagari, ethiopic, farsi, georgian, gujarati, gurmukhi, hebrew, japanese, kannada, khmer, korean, lao, malayalam, myanmar, oriya, sinhala, tamil, telugu, thai, and tibetan.

Each script maps to the corresponding Noto Sans variant on Google Fonts (e.g. "arabic" loads Noto Sans Arabic). All font faces share a single font-family name and use unicode-range so the browser only downloads the files it needs for the characters on the page.

Set to false to disable font injection entirely and use system fonts:

emdash({
fonts: false,
})

The admin CSS uses the --font-emdash CSS variable. This is set automatically by the font configuration above.

Optional. An authentication adapter. EmDash’s built-in login is passkeys; setting auth replaces them with an external provider. The Cloudflare Access adapter, access(), is provided by @emdash-cms/cloudflare:

import { access } from "@emdash-cms/cloudflare";
emdash({
auth: access({
teamDomain: "myteam.cloudflareaccess.com",
audience: "your-app-audience-tag",
roleMapping: {
Admins: 50,
Editors: 40,
},
}),
});

Options for access():

OptionTypeDefaultDescription
teamDomainstringrequiredYour Cloudflare Access team domain
audiencestringApplication Audience (AUD) tag. On Workers, prefer audienceEnvVar.
audienceEnvVarstring"CF_ACCESS_AUDIENCE"Environment variable to read the audience tag from at runtime
autoProvisionbooleantrueCreate an EmDash user on first login
defaultRolenumber30Role level for users not matched by roleMapping (see User roles)
syncRolesbooleanfalseRe-apply roleMapping on every login instead of only at provisioning
roleMappingobjectMap IdP group names to EmDash role levels; first match wins

Optional. An array of pluggable login providers (top-level, alongside auth). Each entry is the result of calling a provider factory, as shown below:

import { github } from "emdash/auth/providers/github";
import { google } from "emdash/auth/providers/google";
import { atproto } from "@emdash-cms/auth-atproto";
emdash({
authProviders: [github(), google(), atproto()],
});

Built-in providers:

  • github() — reads EMDASH_OAUTH_GITHUB_CLIENT_ID / EMDASH_OAUTH_GITHUB_CLIENT_SECRET (or unprefixed fallbacks).
  • google() — reads EMDASH_OAUTH_GOOGLE_CLIENT_ID / EMDASH_OAUTH_GOOGLE_CLIENT_SECRET.
  • atproto() — Atmosphere account login (Bluesky and the wider AT Protocol network). No env vars needed. Accepts { allowedDIDs, allowedHandles, defaultRole }. See the Atmosphere login guide.

Third-party packages can register their own providers using the same AuthProviderDescriptor shape — see Login Providers.

Optional. The public browser-facing origin for the site (scheme + host + optional port, no path).

Behind a TLS-terminating reverse proxy, Astro.url returns the internal address (http://localhost:4321) instead of the public one (https://cms.example.com). This breaks passkeys, CSRF origin matching, OAuth redirects, login redirects, MCP discovery, snapshot exports, sitemap, robots.txt, and JSON-LD structured data. Set siteUrl to fix all of these at once.

The integration validates this value at load time: it must be a valid URL with http: or https: protocol and is normalized to origin (path is stripped).

The following example sets the public origin:

emdash({
database: sqlite({ url: "file:./data.db" }),
storage: local({
directory: "./uploads",
baseUrl: "/_emdash/api/media/file",
}),
siteUrl: "https://cms.example.com",
});

When siteUrl is not set in config, EmDash checks environment variables in order: EMDASH_SITE_URL, then SITE_URL. This is useful for container deployments where the public URL is set at runtime.

On Cloudflare Workers, the env-var fallback reads process.env, which is empty unless the nodejs_compat_populate_process_env compatibility flag is enabled. To use the env var instead of the config option there, set both:

wrangler.jsonc
{
"compatibility_flags": ["nodejs_compat", "nodejs_compat_populate_process_env"],
"vars": { "EMDASH_SITE_URL": "https://cms.example.com" },
}

siteUrl defines a single canonical origin. When the same EmDash deployment is reachable under several hostnames that share a registrable parent domain (e.g. https://example.com and https://preview.example.com), passkey verification rejects assertions whose origin doesn’t match siteUrl exactly — even though WebAuthn allows passkeys to be valid across subdomains under the same rpId.

Declare additional accepted origins via either allowedOrigins in astro.config.mjs or the EMDASH_ALLOWED_ORIGINS env var. The canonical siteUrl remains the source of rpId; entries listed here are accepted at verification time. The two sources are merged at runtime, so config can declare the stable origins (versioned, code-reviewed) while env adds environment-specific extras (e.g. ephemeral PR previews).

The following example declares one extra origin in config:

astro.config.mjs
emdash({
siteUrl: "https://example.com",
allowedOrigins: ["https://preview.example.com"],
})

The equivalent values can also come from environment variables:

.env / wrangler.jsonc / Docker env
EMDASH_SITE_URL=https://example.com
EMDASH_ALLOWED_ORIGINS=https://preview.example.com,https://staging.example.com

EmDash validates these to prevent dead config the browser would never honor:

  • Each entry must be a parseable http: or https: URL with no trailing dot and no empty labels in the hostname.
  • When allowedOrigins is non-empty, siteUrl must be set (either source) and must not be an IP literal or have a trailing-dot hostname.
  • Each origin must be the same hostname as siteUrl or a subdomain of it. (WebAuthn requires rpId to be a registrable suffix of every origin.)

When validation fails, you’ll see a source-attributed error like EmDash config error in EMDASH_ALLOWED_ORIGINS: "https://other-site.com" is not a subdomain of siteUrl "https://example.com". Allowed origins must be the same hostname as siteUrl or a subdomain of it.

Where the error surfaces depends on where the values are declared:

  • At Astro startup, when both config.allowedOrigins and config.siteUrl come from astro.config.mjs — typos in code fail the build.
  • At first passkey verification, when either value comes from EMDASH_ALLOWED_ORIGINS or EMDASH_SITE_URL — env mismatches surface as 500s on the first verify attempt.

Astro only reflects X-Forwarded-* when the public host is allowed. Configure security.allowedDomains for the hostname (and schemes) your users hit. In astro dev, add matching vite.server.allowedHosts so Vite accepts the proxy Host header.

Prefer fixing allowedDomains (and forwarded headers) first; use siteUrl when the reconstructed URL still diverges from the browser origin (typical when TLS is terminated in front and the upstream request stays http://).

With TLS in front, binding the dev server to loopback (astro dev --host 127.0.0.1) is often enough: the proxy connects locally while siteUrl matches the public HTTPS origin.

If your proxy writes a client-IP header, set trustedProxyHeaders so EmDash’s rate limits can use the real client IP instead of bucketing every request under a shared “unknown” key.

The following configuration sets allowedDomains, vite.server.allowedHosts, and siteUrl together for a reverse-proxy deployment:

astro.config.mjs (excerpt)
import { defineConfig } from "astro/config";
import emdash, { local } from "emdash/astro";
import { sqlite } from "emdash/db";
export default defineConfig({
security: {
allowedDomains: [
{ hostname: "cms.example.com", protocol: "https" },
{ hostname: "cms.example.com", protocol: "http" },
],
},
vite: {
server: {
allowedHosts: ["cms.example.com"],
},
},
integrations: [
emdash({
database: sqlite({ url: "file:./data.db" }),
storage: local({
directory: "./uploads",
baseUrl: "/_emdash/api/media/file",
}),
siteUrl: "https://cms.example.com",
}),
],
});

Optional. Headers to trust for client-IP resolution when running behind a reverse proxy you control. Used by auth rate limits (magic-link, signup, passkey, OAuth device flow) and the public comment endpoint.

On Cloudflare the cf object attached to the request is used automatically — you normally do not need to set this. On self-hosted deployments behind nginx, Caddy, Traefik, Fly, Railway, or similar, set this to the header your proxy writes so rate limits can bucket by real client IP instead of treating every request as “unknown”.

The following example trusts the x-real-ip header set by nginx, Caddy, or Traefik:

emdash({
database: sqlite({ url: "file:./data.db" }),
trustedProxyHeaders: ["x-real-ip"],
});

Headers are tried in order. Values matching *-forwarded-for are parsed as comma-separated lists and the first entry is used. The following example prefers Fly.io’s header and falls back to x-forwarded-for:

emdash({
trustedProxyHeaders: ["fly-client-ip", "x-forwarded-for"],
});

When not set in config, EmDash reads the EMDASH_TRUSTED_PROXY_HEADERS env var (comma-separated). An explicit empty array in config overrides the env var.

Optional. Maximum allowed media file upload size in bytes. Applies to both direct multipart uploads and signed-URL uploads. Defaults to 52_428_800 (50 MB). The following example raises the limit to 100 MB:

emdash({
database: sqlite({ url: "file:./data.db" }),
storage: local({
directory: "./uploads",
baseUrl: "/_emdash/api/media/file",
}),
maxUploadSize: 100 * 1024 * 1024, // 100 MB
});
ValueDescription
number (bytes)Must be a positive finite integer
omittedDefaults to 50 MB

Uploads that exceed the configured limit are rejected with a 413 Payload Too Large response on the direct upload path, or a 400 Validation Error on the signed-URL path.

Optional. Controls how the editor toolbar (the floating pill on public pages) is delivered. Defaults to "server".

ValueBehavior
"server" (default)The toolbar is injected server-side into every HTML response rendered for an authenticated editor.
"client"Public HTML is identical for every visitor. A tiny bootstrap script shows an “Edit” pill in browsers that have logged into the admin; clicking it verifies the session and reloads the page with an _edit query param, which is always rendered fresh (never cached) with the full toolbar.
falseNever render the toolbar or the bootstrap script.
emdash({
toolbar: "client",
})

Use "client" when your public HTML is served through a shared cache (Cloudflare Cache Everything / Workers Cache, Fastly, Varnish, …). With server-side injection, an editor browsing the public site receives the cached anonymous variant — without the toolbar — whenever an anonymous visitor primed the cache first, so the toolbar appears and disappears with cache state. In client mode nothing session-specific is injected into shareable HTML, so the cache stays fully effective and the toolbar is reliable.

Notes on "client" mode:

  • Logged-out visitors who open a shared ?_edit URL are redirected to the canonical URL, so the param can’t leak drafts or prime extra cache entries with page content.
  • The “logged in” signal is a non-secret localStorage flag set by the admin; the pill verifies the real session before entering the edit view.
  • The bootstrap is a small inline <script>. If your site sends a strict Content-Security-Policy without 'unsafe-inline', add a hash for it — the same applies to the server-injected toolbar.
  • EmDash injects nothing session-specific — but if your own templates branch on Astro.locals.user (e.g. an “Admin” nav link for logged-in users), that variance is still in your HTML and still fragments the cache.

In every mode, the toolbar can be dismissed in the browser via its × button (per-browser, until the next time an editor opens the admin). Preview and edit-mode responses always render server-side with Cache-Control: private, no-store.

Optional. Opt-in features whose behaviour or wire format may change, or be removed, in a minor release. Each field is independently enabled.

Optional. Point the admin dashboard’s plugin browse and install flows at a federated plugin registry instead of the central marketplace. Requires sandboxRunner, because registry plugins run sandboxed.

Pass a bare aggregator URL string, or an object when you need a labeller or a release-age policy. The following example uses the object form:

astro.config.mjs
emdash({
sandboxRunner: "@emdash-cms/sandbox-cloudflare",
experimental: {
registry: {
aggregatorUrl: "https://registry.emdashcms.com",
acceptLabelers: "did:plc:emdashverification",
policy: {
minimumReleaseAge: "48h",
minimumReleaseAgeExclude: ["did:plc:yourfirstpartydid"],
},
},
},
});
OptionTypeDescription
aggregatorUrlstringAggregator origin where the registry’s XRPC endpoints are mounted. HTTPS in production.
acceptLabelersstringComma-separated labeller DIDs forwarded to the aggregator for takedown and verification labels.
policy.minimumReleaseAgestring | numberHold back releases newer than this age. Duration string ("48h", "7d") or seconds.
policy.minimumReleaseAgeExcludestring[]DIDs (or <did>/<slug> pairs) exempt from the holdback.

See The plugin registry for the full workflow, trust model, and how to query the registry from your own site.

Import the adapters from emdash/db:

import { sqlite, libsql, postgres } from "emdash/db";

SQLite database using better-sqlite3. The following example connects to a local file:

OptionTypeDescription
urlstringFile path with file: prefix
sqlite({ url: "file:./data.db" });

libSQL database. The following example connects to a remote libSQL database:

OptionTypeDescription
urlstringDatabase URL
authTokenstringRuntime auth token (optional for local files)
migrationAuthTokenEnvstringMigration token variable name (default TURSO_AUTH_TOKEN)
libsql({
url: process.env.LIBSQL_DATABASE_URL,
authToken: process.env.LIBSQL_AUTH_TOKEN,
});

PostgreSQL database with connection pooling.

OptionTypeDescription
connectionStringstringPostgreSQL connection URL
hoststringDatabase host
portnumberDatabase port
databasestringDatabase name
userstringDatabase user
passwordstringDatabase password
sslbooleanEnable SSL
pool.minnumberMinimum pool size (default: 0)
pool.maxnumberMaximum pool size (default: 10)
migrationConnectionStringEnvstringMigration connection-string variable name (default DATABASE_URL)

The following example connects with a connection string:

postgres({ connectionString: process.env.DATABASE_URL });

Cloudflare D1 database. Import from @emdash-cms/cloudflare.

OptionTypeDefaultDescription
bindingstringD1 binding name from wrangler.jsonc
sessionstring"disabled"Read replication mode: "disabled", "auto", or "primary-first"
bookmarkCookiestring"__em_d1_bookmark"Cookie name for session bookmarks

The following example shows a basic binding and one with read replicas enabled:

// Basic
d1({ binding: "DB" });
// With read replicas
d1({ binding: "DB", session: "auto" });

When session is "auto" or "primary-first", EmDash uses the D1 Sessions API to route read queries to nearby replicas. Authenticated users get bookmark-based read-your-writes consistency. See Database Options — Read Replicas for details.

Import local and s3 from emdash/astro. The r2 adapter is imported from @emdash-cms/cloudflare:

import emdash, { local, s3 } from "emdash/astro";
import { r2 } from "@emdash-cms/cloudflare";

Local filesystem storage. The following example serves uploads from a local directory:

OptionTypeDescription
directorystringDirectory path
baseUrlstringBase URL for serving files
local({
directory: "./uploads",
baseUrl: "/_emdash/api/media/file",
});

Cloudflare R2 binding. The following example uses an R2 binding with a public URL:

OptionTypeDescription
bindingstringR2 binding name
publicUrlstringOptional public URL
r2({
binding: "MEDIA",
publicUrl: "https://pub-xxxx.r2.dev",
});

S3-compatible storage. All config fields are optional: any field omitted from s3({...}) is resolved from the matching S3_* environment variable when the Node process starts. Explicit values always take precedence.

Prerequisite: install @aws-sdk/client-s3 and @aws-sdk/s3-request-presigner in your project. EmDash core does not bundle the AWS SDK. See Storage Options: S3-Compatible Storage for details.

OptionTypeDescription
endpointstringS3 endpoint URL (S3_ENDPOINT)
bucketstringBucket name (S3_BUCKET)
accessKeyIdstringAccess key (S3_ACCESS_KEY_ID)
secretAccessKeystringSecret key (S3_SECRET_ACCESS_KEY)
regionstringRegion, default "auto" (S3_REGION)
publicUrlstringOptional CDN URL (S3_PUBLIC_URL)

The following examples resolve all fields from the environment, mix config and environment, or pass every field explicitly:

// All fields from S3_* environment variables (Node container deployments)
s3()
// Mix: CDN from config, rest from environment
s3({ publicUrl: "https://cdn.example.com" })
// All explicit
s3({
endpoint: "https://xxx.r2.cloudflarestorage.com",
bucket: "media",
accessKeyId: process.env.R2_ACCESS_KEY_ID,
secretAccessKey: process.env.R2_SECRET_ACCESS_KEY,
publicUrl: "https://cdn.example.com",
})

Runtime environment variable resolution is a Node-only feature. On Cloudflare Workers, secrets and variables are exposed through the env parameter of the fetch handler, not through process.env, so S3_* environment variables are not picked up. Workers deployments should either use the r2(config) adapter or pass explicit values to s3({...}). See Storage Options for details.

Pass one of these to the objectCache option.

Cloudflare KV backend, shared across all isolates. Import from @emdash-cms/cloudflare.

kvCache({
binding: "CACHE", // KV binding name (required)
defaultTtl: 3600, // entry TTL in seconds (optional, KV minimum 60)
revalidate: 1000, // cross-isolate staleness window in ms (optional)
timeout: 2000, // per-op timeout in ms before a miss (optional, 0 disables)
keyPrefix: "em", // cache key prefix (optional)
})

In-process backend for Node.js and development. Import from emdash/astro.

memoryCache({
defaultTtl: 3600, // entry TTL in seconds (optional)
revalidate: 1000, // staleness window in ms (optional)
maxEntries: 1000, // max cached keys before eviction (optional)
keyPrefix: "em", // cache key prefix (optional)
})

See Object Cache for setup and behavior.

Configure the EmDash loader in src/live.config.ts:

src/live.config.ts
import { defineLiveCollection } from "astro:content";
import { emdashLoader } from "emdash/runtime";
export const collections = {
_emdash: defineLiveCollection({
loader: emdashLoader(),
}),
};

The emdashLoader() function takes no arguments:

emdashLoader();

EmDash respects these environment variables:

VariableDescription
EMDASH_SITE_URLPublic browser-facing origin (falls back to SITE_URL)
EMDASH_ALLOWED_ORIGINSComma-separated list of additional origins accepted by passkey verification (multi-subdomain deployments).
EMDASH_DATABASE_URLOverride database URL
EMDASH_ENCRYPTION_KEYKey for encrypting plugin secrets at rest. Operator-provided — never stored in the database.
EMDASH_PREVIEW_SECRETOptional override for preview HMAC secret. When unset, a stable per-site value is generated and stored in the database.
EMDASH_IP_SALTOptional override for the commenter-IP hash salt. When unset, a stable per-site value is generated and stored in the database.
EMDASH_AUTH_SECRETLegacy. Used as the IP-salt source if set; existing installs should keep this to preserve stable commenter-IP hashes across upgrade.
EMDASH_TURNSTILE_SECRET_KEYCloudflare Turnstile secret key (falls back to TURNSTILE_SECRET_KEY). When set, comment submissions must include a valid Turnstile token — pair it with the turnstileSiteKey prop on <CommentForm>.
EMDASH_URLRemote EmDash URL for schema sync

Generate an encryption key with the following command:

Terminal window
npx emdash secrets generate

Templates and sites can declare optional metadata under an emdash key in package.json:

package.json
{
"emdash": {
"label": "My Blog Template",
"seed": ".emdash/seed.json",
"url": "https://my-site.pages.dev"
}
}
OptionDescription
labelTemplate name for display
seedPath to seed JSON file
urlRemote URL for schema sync

EmDash generates types in .emdash/types.ts. Add a path alias to your tsconfig.json:

tsconfig.json
{
"compilerOptions": {
"paths": {
"@emdash-cms/types": ["./.emdash/types.ts"]
}
}
}

Generate types with the following command:

Terminal window
npx emdash types