Nuxt•2w ago

Issues with ENV in production

I am currently experiencing issues with my docker production setup.

The nuxt config:

runtimeConfig: {
    public: {
      apiBase: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8001",
      sanctum: {
          baseUrl: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8002",
      },
    },
  },

runtimeConfig: {
    public: {
      apiBase: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8001",
      sanctum: {
          baseUrl: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8002",
      },
    },
  },

runtimeConfig: {
    public: {
      apiBase: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8001",
      sanctum: {
          baseUrl: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8002",
      },
    },
  },

runtimeConfig: {
    public: {
      apiBase: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8001",
      sanctum: {
          baseUrl: process.env.NUXT_PUBLIC_API_URL || "http://localhost:8002",
      },
    },
  },

Docker

frontend:
    image: IMAGE
    container_name: smartlab-frontend
    restart: always
    environment:
      - NUXT_PUBLIC_API_URL=DOMAIN
    ports:
      - "3002:3000"
    depends_on:
      - api
    networks:
      - smartlab-net

frontend:
    image: IMAGE
    container_name: smartlab-frontend
    restart: always
    environment:
      - NUXT_PUBLIC_API_URL=DOMAIN
    ports:
      - "3002:3000"
    depends_on:
      - api
    networks:
      - smartlab-net

frontend:
    image: IMAGE
    container_name: smartlab-frontend
    restart: always
    environment:
      - NUXT_PUBLIC_API_URL=DOMAIN
    ports:
      - "3002:3000"
    depends_on:
      - api
    networks:
      - smartlab-net

frontend:
    image: IMAGE
    container_name: smartlab-frontend
    restart: always
    environment:
      - NUXT_PUBLIC_API_URL=DOMAIN
    ports:
      - "3002:3000"
    depends_on:
      - api
    networks:
      - smartlab-net

FROM node:24-alpine AS prod
WORKDIR /app

# Copy built output and package files
COPY --from=build /app/.output ./.output
COPY --from=build /app/package.json ./package.json
COPY --from=build /app/package-lock.json ./package-lock.json

# Install only production dependencies
RUN npm ci --omit=dev

# Expose Nuxt production port
EXPOSE 3000

# Start Nuxt 4 production server
CMD ["node", ".output/server/index.mjs"]

FROM node:24-alpine AS prod
WORKDIR /app

# Copy built output and package files
COPY --from=build /app/.output ./.output
COPY --from=build /app/package.json ./package.json
COPY --from=build /app/package-lock.json ./package-lock.json

# Install only production dependencies
RUN npm ci --omit=dev

# Expose Nuxt production port
EXPOSE 3000

# Start Nuxt 4 production server
CMD ["node", ".output/server/index.mjs"]

FROM node:24-alpine AS prod
WORKDIR /app

# Copy built output and package files
COPY --from=build /app/.output ./.output
COPY --from=build /app/package.json ./package.json
COPY --from=build /app/package-lock.json ./package-lock.json

# Install only production dependencies
RUN npm ci --omit=dev

# Expose Nuxt production port
EXPOSE 3000

# Start Nuxt 4 production server
CMD ["node", ".output/server/index.mjs"]

FROM node:24-alpine AS prod
WORKDIR /app

# Copy built output and package files
COPY --from=build /app/.output ./.output
COPY --from=build /app/package.json ./package.json
COPY --from=build /app/package-lock.json ./package-lock.json

# Install only production dependencies
RUN npm ci --omit=dev

# Expose Nuxt production port
EXPOSE 3000

# Start Nuxt 4 production server
CMD ["node", ".output/server/index.mjs"]

This doesnt work can anyone help me with how i should set up the enviroment variables in a production?

kapa.ai•12/9/25, 8:07 PM

Hi @Lars. I'm kapa.ai, your friendly support bot. I will try to answer your question by searching through the knowledge base. :wave:

kapa.ai•12/9/25, 8:07 PM

----------------------
Nuxt’s runtime config is resolved at build time, not when you start the already-built server. In your setup, the Docker environment:environment: block is only available to the runtime container, but your

nuxt.config

nuxt.config

was already evaluated during the earlier

build

build

stage, so process.env.NUXT_PUBLIC_API_URLprocess.env.NUXT_PUBLIC_API_URL was empty then and the fallback (<http://localhost:8001<http://localhost:8001>) got baked into

.output

.output

.

This matches how Nuxt loads env vars:

.env

.env

process.env

process.env

are read during nuxi buildnuxi build, and you can override runtime config with NUXT_NUXT_-prefixed vars, but only if they exist at build time or are used via the documented override mechanism.[nuxt.config env; runtime env vars]

From the sources, there are two working patterns:

**Use `NUXT_`-prefixed env vars and read them via `process.env` in `nuxt.config` at build time** Example (adapted from a working answer):[[nuxt env docker](<https://stackoverflow.com/questions/77438972>); [api base env](<https://stackoverflow.com/questions/77518647>)]```ts// nuxt.config.tsexport default defineNuxtConfig({ runtimeConfig: { public: { apiBase: process.env.NUXT_PUBLIC_API_URL '<http://localhost:8002',> }, }, },})```Then ensure `NUXT_PUBLIC_API_URL` is set **in the environment where you run `nuxi build`**, not only in the final runtime container. For Docker, that usually means:
- Either building with --build-arg--build-arg and exporting it before nuxi buildnuxi build, or
- Mounting / copying a
```
.env
```
```
.env
```
  into the build stage so Nuxt can read it (Nuxt has built‑in dotenv support at build time).[nuxt .env]

kapa.ai•12/9/25, 8:07 PM

Explicitly pass env vars into the container and read them via
process.env
process.env
in
nuxt.config
nuxt.config

In a Docker‑compose example, the answer shows:

nuxt-app:
  environment:
    NUXT_PUBLIC_STRAPI_BASE_URI: "blablabla"

nuxt-app:
  environment:
    NUXT_PUBLIC_STRAPI_BASE_URI: "blablabla"

and then in

nuxt.config

nuxt.config

runtimeConfig: {
  public: {
    strapiBaseUri: process.env.NUXT_PUBLIC_STRAPI_BASE_URI,
  },
}

runtimeConfig: {
  public: {
    strapiBaseUri: process.env.NUXT_PUBLIC_STRAPI_BASE_URI,
  },
}

But again, this only works if that env var is present when

nuxt.config

nuxt.config

is evaluated (i.e. at build time).[nuxt docker env]

In your current multi‑stage Dockerfile, the build stage (not shown) is where nuxi buildnuxi build runs. That stage likely doesn’t have NUXT_PUBLIC_API_URLNUXT_PUBLIC_API_URL set, so the value never makes it into

.output

.output

. Setting environment:environment: only on the final

frontend

frontend

service won’t change the already‑built config.

To fix your setup based on the sources:

Ensure NUXT_PUBLIC_API_URLNUXT_PUBLIC_API_URL is available during the build stage (e.g. via
```
.env
```
```
.env
```
at project root or Docker build args) so process.env.NUXT_PUBLIC_API_URLprocess.env.NUXT_PUBLIC_API_URL has the right value when
```
nuxt.config
```
```
nuxt.config
```
runs.[nuxt .env]
Keep your runtimeConfigruntimeConfig as you have it; the main change is where/when the env var is provided.

If you need a pattern that was confirmed to work for switching API URLs between environments, the docs‑based solution is to use NUXT_PUBLIC_API_BASENUXT_PUBLIC_API_BASE (or similar) and map it directly in runtimeConfig.publicruntimeConfig.public as shown here:[api base env]

runtimeConfig: {
  public: {
    apiBase: process.env.NUXT_PUBLIC_API_BASE,
  },
}

runtimeConfig: {
  public: {
    apiBase: process.env.NUXT_PUBLIC_API_BASE,
  },
}

----------------------
Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:
----------------------

kapa.ai•12/9/25, 8:07 PM

@614440001027047434 Kapa.ai is still learning and improving, please let me know how I did by reacting below.

LarsOP•12/9/25, 8:09 PM

@kapa.ai in nuxt 3 it used to be possible to read a .env after build time right?

kapa.ai•12/9/25, 8:09 PM

Let me check the knowledge base for you again. One moment! :books:

kapa.ai•12/9/25, 8:10 PM

----------------------
The knowledge sources don’t explicitly state that Nuxt 3 ever supported changing

.env

.env

after build and having that affect an already-built app.

What they do say:

Nuxt has built‑in dotenv support at dev/build/generate time: a
```
.env
```
```
.env
```
in the project root is “automatically loaded at dev, build and generate time. Any environment variables set there will be accessible within your nuxt.config file and modules.”[Nuxt .env support]
That’s clearly about build‑time, not post‑build.
There was a fix so that when
```
.env
```
```
.env
```
changes during nuxi devnuxi dev, Nuxt does a hard reload to reload variables, again in the context of development, not a built artifact.[Reload on .env change]

Nothing in the provided sources describes a supported mechanism where a production build reads a new

.env

.env

file after nuxi buildnuxi build has run and updates runtimeConfigruntimeConfig accordingly. All examples that work rely on env vars being present when
nuxt.config
nuxt.config
is evaluated (dev/build/generate), or on using

process.env

process.env

directly in server code, but not on late‑loading

.env

.env

after build.[Nuxt .env support; runtime config/env]

So, based only on these sources, I can’t confirm that “reading

.env

.env

after build time” was ever an intended or supported Nuxt 3 feature.
----------------------
Note: you can ask me a follow up question by @ mentioning me again :speech_balloon:
----------------------

kapa.ai•12/9/25, 8:10 PM

@614440001027047434 Kapa.ai is still learning and improving, please let me know how I did by reacting below.

Issues with ENV in production

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