ConvertX with Docker Compose

What ConvertX needs

Only figures ConvertX'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.

Which hardware ConvertX has images for

Read from each image's manifest list in its registry (anonymous, read-only) when this page was built. An app counts for a CPU only if every one of its images lists it.

• x86-64 PC or NAS (linux/amd64): every image has a build.
• Raspberry Pi 4/5, 64-bit OS (linux/arm64): every image has a build.
• Raspberry Pi 3 or Zero 2 W, 32-bit OS (linux/arm/v7): no image for convertx. No image for this hardware; the builder leaves the app out.

A manifest says an image exists for a CPU, not how well ConvertX runs on it: a build for arm64 or arm/v7 can still be too slow or need more memory than the board has. The RAM and disk ConvertX publishes are in the table above and, for a whole set of apps against a Raspberry Pi, on Will it run on my machine?. A tag like latest can move to a new digest after the date checked.

docker-compose.yml

This is exactly what the builder writes for ConvertX 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: ConvertX
# 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"

  # ---- ConvertX (convert.example.org) ----
  # Source: https://github.com/C4illin/ConvertX/blob/main/README.md (checked 2026-10-03)
  # Changed: Removed the documented '3000:3000' port and container_name; Caddy reaches convertx:3000 on the proxy network.
  #          JWT_SECRET, the README's example string, is a generated value in .env ("JWT_SECRET is recommended to be set").
  convertx:
    image: "ghcr.io/c4illin/convertx"
    container_name: "convertx"
    restart: "unless-stopped"
    environment:
      PUID: "1000"
      JWT_SECRET: "${CONVERTX_JWT_SECRET}"
    volumes:
      - "./convertx/data:/app/data"
    networks:
      proxy: {}

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"

volumes:
  caddy-data:
  caddy-config:

Caddyfile save as caddy/Caddyfile

Caddy gets and renews the HTTPS certificate for convert.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.

# ConvertX
convert.example.org {
	reverse_proxy convertx:3000
}

Already running nginx, Nginx Proxy Manager, Caddy or Traefik? The reverse-proxy settings ConvertX needs, for all four, each cited to ConvertX's own docs.

.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 ConvertX, from dankhost.com/app/convertx/. Fill the blank secret before starting.
# Keep this file private (chmod 600).

# ConvertX
# 48 random letters and digits: the builder fills this in your browser
CONVERTX_JWT_SECRET=

Changes from the official file

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

• Removed the documented '3000:3000' port and container_name; Caddy reaches convertx:3000 on the proxy network.
• JWT_SECRET, the README's example string, is a generated value in .env ("JWT_SECRET is recommended to be set").

Notes for ConvertX behind the proxy

• Open https://convert.example.org straight after the first start and create your account: the README warns that anyone can register the first one. Later accounts need ACCOUNT_REGISTRATION=true, which the README says never to combine with a public address.
• Converted files and uploads are deleted after 24 hours (AUTO_DELETE_EVERY_N_HOURS, 0 turns it off).
• PUID=1000 should match the owner of ./convertx/data on the host (id -u); if you see "unable to open database file", fix the folder's owner, as the README says.
• The image has no tag, which is latest, the README's recommendation for normal use (:main follows every commit).

Back it up

ConvertX publishes no backup procedure. ./data holds its SQLite database (accounts and conversion history) and the files waiting to be downloaded, which it deletes after 24 hours anyway.

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: ConvertX

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)

## ConvertX

ConvertX publishes no backup procedure. ./data holds its SQLite database (accounts and conversion history) and the files waiting to be downloaded, which it deletes after 24 hours anyway.

What this compose mounts:
- ./convertx/data (/app/data in convertx)
  BACK UP: the SQLite database with accounts and history, and uploaded and converted files (kept 24 hours).

1. Stop convertx. Stopping it keeps the SQLite database from changing mid-copy.

    docker compose stop convertx

2. Copy while convertx is stopped:

    tar czf "$BACKUP/convertx-data.tar.gz" ./convertx/data

3. Start it again:

    docker compose start convertx

Restore check:

    tar tzf "$BACKUP/convertx-data.tar.gz" > /dev/null && echo OK

Put a copy back (with convertx stopped):

    tar xzf "$BACKUP/convertx-data.tar.gz"   # recreates ./convertx/data; move the old folder aside first

Stop it, put ./convertx/data back, start it.

Sources:
- ConvertX README (Docker Compose, environment variables, image tags): https://github.com/C4illin/ConvertX/blob/main/README.md (checked 2026-10-03)
- 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 2026-10-03)

Update it

What docker compose pull does depends only on how each image line in the compose file above is tagged. For ConvertX as this page writes it:

What ConvertX's docs say about updating

ConvertX publishes no update procedure for this setup; the steps below are Docker's generic method.

The steps

1. Back up first, as in Back it up above. An update can migrate ConvertX's data on its first start; the copy is the way back.
2. Download the new images. Running containers are not touched yet:

   docker compose pull

3. Recreate the containers whose image changed. Volumes and bind-mounted folders stay as they are:

   docker compose up -d

4. Watch ConvertX start (Ctrl+C stops following the log, not the app):

   docker compose logs -f convertx

5. Optional: remove the old images the pull left without a tag. This covers every stack on the machine, not only this one:

   docker image prune

Docker's reference for these commands: Docker docs: docker compose pull checked 2026-09-30; Docker docs: docker compose up (recreates changed containers, keeps volumes) checked 2026-09-30; Docker docs: docker image prune checked 2026-09-30

Sources

Every page below was fetched on the date shown.

• ConvertX on GitHub (repository description) checked 2026-10-03 (what it does)
• ConvertX README (Docker Compose, environment variables, image tags) checked 2026-10-03 (compose definition and proxy settings, backup plan)
• 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)
• Docker docs: Volumes, Back up, restore, or migrate data volumes checked 2026-10-03 (backup plan)
• Caddy docs: Conventions, Data directory checked 2026-09-24 (backup plan)
• Docker docs: docker compose pull checked 2026-09-30 (update steps)
• Docker docs: docker compose up (recreates changed containers, keeps volumes) checked 2026-09-30 (update steps)
• Docker docs: docker image prune checked 2026-09-30 (update steps)

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