homarr/.agents/skills/codebase-context/references/architecture.md

Homarr architecture

Contents

• Applications and runtimes
• Package map
• Dependency direction
• Core patterns
• Commands and conventions

Applications and runtimes

Path	Role
apps/nextjs	Main Next.js application and HTTP APIs on port 3000
apps/docs	Next.js and Fumadocs documentation site on port 3003
apps/tasks	Cron-job initialization and scheduling runtime; it does not expose the old port-3002 API
apps/websocket	tRPC WebSocket subscriptions on port 3001
apps/workshop	Go/PocketBase Workshop service and provider integration

pnpm dev runs only @homarr/nextjs. Use pnpm --filter @homarr/tasks dev, pnpm --filter @homarr/websocket dev, or pnpm dev:docs when a task needs those runtimes.

In production, apps/nextjs/src/instrumentation-node.ts starts the tasks and WebSocket runtimes inside the Node process. Nginx listens on port 7575, proxies /websockets to port 3001, and sends other traffic to port 3000. Redis can run internally or externally.

Package map

Foundation and domain

• core: environment validation, database and Redis factories, logging, infrastructure.
• definitions: domain enums, integration definitions, widget kinds, permissions.
• common: shared utilities with environment-specific entrypoints. Search it before adding helpers.
• validation: shared Zod schemas.
• server-settings: typed server-setting keys and access.

Data, identity, and transport

• db: Drizzle schemas, queries, migrations, and three database drivers.
• auth: Auth.js/NextAuth configuration, sessions, providers, and API keys.
• api: tRPC routers, contexts, MCP metadata extraction, OpenAPI, and client/server entrypoints.
• redis: Redis clients, pub/sub channels, and caches.
• cron-jobs-core, cron-jobs, cron-job-status: scheduling primitives, job implementations, and status transport.

Backends and external systems

• integrations: typed clients for external applications.
• request-handler: shared server request flows.
• docker, ping, image-proxy, icons, analytics: bounded infrastructure capabilities.
• custom-widgets: Custom JSX v2 schema, validation, runtime, and security contracts.
• workshop: TypeScript Workshop client, backend contracts, and schemas used by Homarr.

UI and composed features

• ui: shared Mantine components, theme, and hooks. Search here before creating a primitive.
• form, forms-collection: Zod-backed form setup and reusable forms.
• modals, modals-collection: modal primitives and feature modals.
• boards: board state, edit mode, and cache coordination.
• settings, spotlight, notifications, onboarding: cross-feature UI flows.
• widgets: widget definitions, dynamic component loaders, and shared widget UI.
• translation: next-intl configuration and locale catalogs.
• cli: Node operations CLI. tools/homarr-dev is the separate Go developer CLI.

Dependency direction

Prefer these directions; verify the exact dependency in package manifests before changing a boundary.

1. Put infrastructure in core and stable domain names in definitions.
2. Put reusable, dependency-light helpers in common; use its public environment-specific entrypoints.
3. Build persistence in db, identity in auth, transport in redis, and external clients in integrations.
4. Compose server behavior in api, cron-jobs, and request-handler packages.
5. Build primitives in ui, form, and modals; compose product surfaces in widgets and collection packages.
6. Keep app entrypoints in apps/* thin. Avoid moving reusable behavior into apps/nextjs when a package already owns it.

Core patterns

tRPC and MCP

packages/api/src/root.ts lazily composes the application router. Server components use @homarr/api/server; client components use @homarr/api/client. MCP extraction requires the eager router in packages/api/src/mcp.ts, so MCP-enabled subrouters must be imported and registered there directly. Use the mcp-integration skill for exposure and security rules.

Databases

Drizzle schemas live in packages/db/schema/. DB_DRIVER selects better-sqlite3 or node-postgres; MySQL and MariaDB are no longer runtime drivers in v2. Existing MySQL installations must use the documented converter before upgrading. Migrations live under packages/db/migrations/sqlite/ and packages/db/migrations/postgresql/.

Widgets

packages/widgets/src/registry.ts owns the explicit widget-module and component-loader registries. packages/widgets/src/manifest.ts caches those loaders and exposes definitions, components, and combined resources. Widget modules use createWidgetDefinition and typed option builders. Data commonly comes from tRPC queries or Redis-backed cron results. Use existing shared widget components before creating local variants.

Integrations

packages/definitions/src/integration.ts owns integrationDefs and IntegrationKind. packages/integrations/src/base/creator.ts owns createIntegrationAsync; concrete integrations implement the shared base contract. Keep credentials and permission checks on server-owned paths.

Cron jobs

Jobs live in packages/cron-jobs/src/jobs/ and use createCronJob. apps/tasks initializes and starts the job group. Job results and status can flow through Redis and tRPC; the retired port-3002 management-API model is no longer part of the architecture.

Routing and localization

User routes live below apps/nextjs/src/app/[locale]/; the locale segment does not add a URL prefix. Route groups organize home and board surfaces. Administrative routes live under manage, Custom Widget configuration has a token route, and Workshop has a management surface.

Custom Widgets and Workshop

packages/custom-widgets owns the Custom JSX v2 contract. packages/workshop is the Homarr-side client/contract package; apps/workshop is the separate Go/PocketBase service. Use the homarr-custom-widget skill for authoring and security constraints.

Commands and conventions

• Read current scripts from the root or package package.json; avoid caching commands that do not exist.
• Use pnpm dev for Next.js, pnpm dev:docs for docs, and pnpm dev:cli -- <args> for the Go developer CLI.
• Use pnpm docker:dev:up for the Redis development dependency.
• Follow the Testing section in AGENTS.md for test creation and validation scope.
• Use ~/* only inside the Next.js app. Use public @homarr/* entrypoints across package boundaries.
• Keep Mantine application styles separate from the Tailwind-based docs app.