Open WebUI with Docker Compose

What Open WebUI needs

Only figures Open WebUI's own documentation publishes, each linked to the page it is on. Where the project gives no number, this page does not invent one.

On top of this, Caddy (the reverse proxy in the file) is a single small container. Open WebUI itself runs as 2 containers: open-webui-ollama, open-webui.

docker-compose.yml

This is exactly what the builder writes for Open WebUI alone on example.org: the official definition with its published ports removed and Caddy added in front. Every ${VARIABLE} is defined in the .env below.

# docker-compose.yml built at dankhost.com for: Open WebUI
# Each app block is its official compose definition. Only the names were prefixed with
# the app slug (services, containers, volumes, bind folders, .env variables) so any set of
# apps can share one file; other differences are listed under "Changed:" in each block.
# Only Caddy publishes ports. Secrets live in .env next to this file.

services:
  # ---- Caddy: the one reverse proxy, HTTPS certificates from Let's Encrypt ----
  # Source: https://caddyserver.com/docs/running (checked 2026-09-23)
  # Source: https://github.com/dani-garcia/vaultwarden/wiki/Using-Docker-Compose (checked 2026-09-23)
  # Caddyfile goes in ./caddy/Caddyfile. Fixed address 172.30.0.2 so apps can trust it exactly.
  caddy:
    image: "caddy:2"
    container_name: "caddy"
    restart: "unless-stopped"
    ports:
      - "80:80"
      - "443:443"
      - "443:443/udp"
    volumes:
      - "./caddy:/etc/caddy"
      - "caddy-data:/data"
      - "caddy-config:/config"
    networks:
      proxy:
        ipv4_address: "172.30.0.2"

  # ---- Open WebUI (chat.example.org) ----
  # Source: https://github.com/open-webui/open-webui/blob/main/docker-compose.yaml (checked 2026-09-25)
  # Source: https://docs.openwebui.com/getting-started/quick-start/ (checked 2026-09-25)
  # Changed: Removed the '${OPEN_WEBUI_PORT-3000}:8080' port; Caddy reaches open-webui:8080 on the proxy network. Ollama publishes no port at all: only Open WebUI talks to it, as http://ollama:11434 on the app's own network.
  #          Removed the 'build:' section (it builds the image from a source checkout) so the published image is pulled, and the documented container names 'ollama' and 'open-webui' (the builder names every container after its service).
  #          WEBUI_SECRET_KEY is a generated 64-character key instead of the empty value in the file: the Quick Start says to set it once and keep it, because without a fixed key every recreated container logs everyone out.
  #          Removed extra_hosts host.docker.internal:host-gateway: it lets Open WebUI reach an Ollama running on the host, and here Ollama runs in its own container.
  #          Ollama's network keeps internet access (unlike the private database networks of other apps) so that it can download models.
  open-webui-ollama:
    image: "ollama/ollama:${OPEN_WEBUI_OLLAMA_DOCKER_TAG-latest}"
    container_name: "open-webui-ollama"
    volumes:
      - "open-webui-ollama:/root/.ollama"
    pull_policy: "always"
    tty: true
    restart: "unless-stopped"
    networks:
      open-webui-backend:
        aliases:
          - "ollama"
  open-webui:
    image: "ghcr.io/open-webui/open-webui:${OPEN_WEBUI_WEBUI_DOCKER_TAG-main}"
    container_name: "open-webui"
    volumes:
      - "open-webui:/app/backend/data"
    depends_on:
      - "open-webui-ollama"
    environment:
      OLLAMA_BASE_URL: "http://ollama:11434"
      WEBUI_SECRET_KEY: "${OPEN_WEBUI_WEBUI_SECRET_KEY}"
    restart: "unless-stopped"
    networks:
      proxy: {}
      open-webui-backend: {}

networks:
  # Pinned so the trusted-proxy address given to each app (172.30.0.2) is exact.
  # If "docker compose up" reports "Pool overlaps", change 172.30.0 here, in Caddy's
  # ipv4_address and in every trusted-proxy value to a free 172.x.0 range.
  proxy:
    ipam:
      config:
        - subnet: "172.30.0.0/24"
          ip_range: "172.30.0.128/25"
          gateway: "172.30.0.1"
  open-webui-backend: {}

volumes:
  caddy-data:
  caddy-config:
  open-webui-ollama:
  open-webui:

Caddyfile save as caddy/Caddyfile

Caddy gets and renews the HTTPS certificate for chat.example.org by itself once the DNS record points at your server and ports 80 and 443 reach it.

# Caddyfile built at dankhost.com. Save it as ./caddy/Caddyfile next to docker-compose.yml.
# Caddy gets and renews a Let's Encrypt certificate for each name below by itself,
# once the DNS records point at this server and ports 80 and 443 reach it.

# Open WebUI
chat.example.org {
	reverse_proxy open-webui:8080
}

.env

The secret is left blank here on purpose: a password printed on a public page is the same for everyone who copies it. The builder fills it with random letters and digits made in your browser.

# .env for Open WebUI, from dankhost.com/app/open-webui/. Fill the blank secret before starting.
# Keep this file private (chmod 600).

# Open WebUI
# 64 random letters and digits: the builder fills this in your browser
OPEN_WEBUI_WEBUI_SECRET_KEY=
OPEN_WEBUI_OLLAMA_DOCKER_TAG=latest
OPEN_WEBUI_WEBUI_DOCKER_TAG=main

Changes from the official file

Besides prefixing every service, container, volume, folder and variable with open-webui (so any set of apps can share one file), these are all the differences from what the project documents:

• Removed the '${OPEN_WEBUI_PORT-3000}:8080' port; Caddy reaches open-webui:8080 on the proxy network. Ollama publishes no port at all: only Open WebUI talks to it, as http://ollama:11434 on the app's own network.
• Removed the 'build:' section (it builds the image from a source checkout) so the published image is pulled, and the documented container names 'ollama' and 'open-webui' (the builder names every container after its service).
• WEBUI_SECRET_KEY is a generated 64-character key instead of the empty value in the file: the Quick Start says to set it once and keep it, because without a fixed key every recreated container logs everyone out.
• Removed extra_hosts host.docker.internal:host-gateway: it lets Open WebUI reach an Ollama running on the host, and here Ollama runs in its own container.
• Ollama's network keeps internet access (unlike the private database networks of other apps) so that it can download models.

Notes for Open WebUI behind the proxy

• Open https://chat.example.org and sign up at once: the first account created becomes the administrator.
• Ollama starts with no model. Pull one before your first chat, for example: docker compose exec open-webui-ollama ollama pull llama3.2. The model you pull, not Open WebUI, decides how much RAM and disk this needs; neither project's install page gives a figure.
• This file runs Ollama on the CPU. For an NVIDIA GPU, Open WebUI's Quick Start shows the deploy.resources.reservations.devices block to add to the Ollama service.

Back it up

Open WebUI's backup page lists what /app/backend/data holds: webui.db (the SQLite database with users, chats and settings), uploads/ (uploaded files), vector_db/ (the ChromaDB vector database) and cache/. Its scripts stop the containers before copying. Ollama's models can be downloaded again.

Below is the BACKUP.md the builder writes next to the compose file above: which of its folders and volumes hold data, what to copy with which container stopped, and a restore check. Pick more apps in the builder and it covers them all in one file.

# BACKUP.md built at dankhost.com for: Open WebUI

What to copy from the docker-compose.yml built with this file, the database dump each project documents (rewritten for the service names in that file), what to copy with which container stopped, and how to check the result. Run every command in the folder that holds docker-compose.yml.

The folders are owned by the containers' users: put sudo in front of tar if it says "Permission denied". Named volumes live under /var/lib/docker/volumes, not next to the compose file, so they are copied through a throwaway ubuntu container (Docker's documented --volumes-from method). tar makes a full copy each run; for large folders an incremental tool (restic, borg, rsync) saves time and space.

Never run "docker compose down -v" on this file: it deletes the named volumes of every app in it.

## Before you start

    BACKUP=/mnt/backup/selfhost   # change this: a disk or machine other than this server's system disk
    mkdir -p "$BACKUP"

## Every time: the three stack files

    tar czf "$BACKUP/stack-files.tar.gz" docker-compose.yml .env caddy

.env holds the database passwords and secret keys the apps were set up with; keep this archive as private as the data.

## Caddy (the reverse proxy)

Caddy's docs: 'The data directory must not be treated as a cache.' It holds the TLS certificates and their private keys; without it Caddy has to ask Let's Encrypt for every certificate again.

- caddy-data (named volume, /data in caddy)
  BACK UP: TLS certificates, private keys, OCSP staples.
- caddy-config (named volume, /config in caddy)
  SKIP: the last active configuration, kept for 'caddy run --resume', which this setup does not use: it starts from the Caddyfile.
- ./caddy (/etc/caddy in caddy)
  IN stack-files.tar.gz: the Caddyfile, copied with the stack files above.

Copy (Caddy keeps serving while you copy):

    docker run --rm --volumes-from caddy -v "$BACKUP":/backup ubuntu tar cvf /backup/caddy-data.tar /data

Restore check:

    tar tf "$BACKUP/caddy-data.tar" > /dev/null && echo OK
    docker run --rm --volumes-from caddy -v "$BACKUP":/backup ubuntu bash -c "cd /data && tar xvf /backup/caddy-data.tar --strip 1"

Sources:
- Caddy docs: Conventions, Data directory: https://caddyserver.com/docs/conventions#data-directory (checked 2026-09-24)
- Docker docs: Volumes, Back up, restore, or migrate data volumes: https://docs.docker.com/engine/storage/volumes/#back-up-restore-or-migrate-data-volumes (checked 2026-09-24)

## Open WebUI

Open WebUI's backup page lists what /app/backend/data holds: webui.db (the SQLite database with users, chats and settings), uploads/ (uploaded files), vector_db/ (the ChromaDB vector database) and cache/. Its scripts stop the containers before copying. Ollama's models can be downloaded again.

What this compose mounts:
- open-webui-ollama (named volume, /root/.ollama in open-webui-ollama)
  OPTIONAL: the downloaded models, often several GB each. They can be pulled again with ollama pull; copy them only to save the download.
- open-webui (named volume, /app/backend/data in open-webui)
  BACK UP: webui.db (users, chats, settings), uploads/, vector_db/ and cache/.

1. Stop open-webui. Open WebUI's backup page stops the containers before copying so the SQLite database and the vector store are not written mid-copy.

    docker compose stop open-webui

2. Copy while open-webui is stopped:

    docker run --rm --volumes-from open-webui -v "$BACKUP":/backup ubuntu tar cvf /backup/open-webui.tar /app/backend/data

3. Start it again:

    docker compose start open-webui

Restore check:

    tar tf "$BACKUP/open-webui.tar" > /dev/null && echo OK

Put a copy back (with open-webui stopped):

    docker run --rm --volumes-from open-webui -v "$BACKUP":/backup ubuntu bash -c "cd /app/backend/data && tar xvf /backup/open-webui.tar --strip 3"

Stop it, put the open-webui volume back, start it, then pull the models again if you did not copy the ollama volume.

Sources:
- Open WebUI docs: Backups (what /app/backend/data holds; stop before copying): https://docs.openwebui.com/tutorials/maintenance/backups (checked 2026-09-25)
- Docker docs: Volumes, Back up, restore, or migrate data volumes: https://docs.docker.com/engine/storage/volumes/#back-up-restore-or-migrate-data-volumes (checked 2026-09-25)

Sources

Every page below was fetched on the date shown.

• Open WebUI docs: front page checked 2026-09-25 (what it does)
• Open WebUI repository: docker-compose.yaml (open-webui with an ollama service) checked 2026-09-25 (compose definition and proxy settings)
• Open WebUI docs: Quick Start (Docker Compose, WEBUI_SECRET_KEY, data volume) checked 2026-09-25 (compose definition and proxy settings)
• Caddy docs: Keep Caddy running (Docker Compose section) checked 2026-09-23 (Caddy)
• Vaultwarden wiki: Caddy with HTTP challenge (uses the caddy:2 image) checked 2026-09-23 (Caddy)
• Open WebUI docs: Backups (what /app/backend/data holds; stop before copying) checked 2026-09-25 (backup plan)
• Docker docs: Volumes, Back up, restore, or migrate data volumes checked 2026-09-25 (backup plan)
• Caddy docs: Conventions, Data directory checked 2026-09-24 (backup plan)

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