---
title: Configuration
description: The shared Next.js configuration every app extends.
type: reference
related:
  - /en/docs/packages/next-config/bundle-analysis
  - /en/docs/deployment/docker
---

# Configuration



Every app's `next.config.ts` is three lines:

```ts title="apps/app/next.config.ts"
import { config } from '@kreogen/next-config';

export default config;
```

<Callout type="warn">
  `config` is a single shared object. Prefer `createConfig(overrides)`, which
  returns a fresh one — `apps/web` used to push onto `config.images.remotePatterns`
  directly, so `apps/app` and `apps/api` silently inherited whatever it had done
  to the object all three pointed at. Whether that mattered depended on module
  evaluation order.
</Callout>

## Standalone output

`output: "standalone"` emits a self-contained server bundle for the Docker
runtime stage.

`outputFileTracingRoot` is set to the workspace root, and it is not optional in
a monorepo: without it Next infers the root from the nearest lockfile, and if
that resolves to the app rather than the workspace the standalone output lands
at a path the Dockerfile does not expect.

`outputFileTracingIncludes` pulls in `packages/database/generated`, because
Prisma's client is generated to a custom output path that Next's file tracing
does not follow on its own.

Both are skipped when `VERCEL` is set, since Vercel builds its own output
format and warns about standalone.

## External packages

```ts
serverExternalPackages: ['@prisma/client', '@aws-sdk/client-s3'],
```

Both are Node libraries with native or dynamic requires. Bundling them into the
server output either fails outright or produces something subtly broken at
runtime.

## Images

AVIF and WebP, with `remotePatterns` allowing the OAuth avatar CDNs —
`lh3.googleusercontent.com` and `avatars.githubusercontent.com` — plus the host
derived from `S3_ENDPOINT` when one is set.

That last one is worth knowing about. `next/image` refuses an unlisted host, so
without it every image uploaded through
[`@kreogen/storage`](/en/docs/packages/storage) fails to render — and the
failure looks like a broken upload rather than a missing configuration entry. A
malformed endpoint is ignored here rather than failing the build; that is the
storage package's error to report.

## PostHog proxy

Rewrites that route analytics through your own origin so ad blockers do not
drop them:

| Path                    | Proxies to                      |
| ----------------------- | ------------------------------- |
| `/ingest/static/:path*` | PostHog's static assets         |
| `/ingest/:path*`        | PostHog's ingestion endpoint    |
| `/ingest/decide`        | PostHog's feature flag endpoint |

`skipTrailingSlashRedirect` is set alongside them, because PostHog sends some
requests with a trailing slash and Next's default redirect turns those into a
307 the SDK does not follow. See
[web analytics](/en/docs/packages/analytics/web).

## Other defaults

* `poweredByHeader: false` — server identity is not something to volunteer.
* `reactStrictMode: true`.

## Bundle analysis

`withAnalyzer()` wraps the config; see
[bundle analysis](/en/docs/packages/next-config/bundle-analysis).


---

For a semantic overview of all documentation, see [/sitemap.md](/sitemap.md)

For an index of all available documentation, see [/llms.txt](/llms.txt)