A lightweight Docker container that watches Traefik router labels on your Docker host and automatically creates/updates Hostinger DNS records to point your subdomains at your server's public IP.

How it works

Docker event (container start/stop)
        │
        ▼
  Scan all containers for Traefik labels
  e.g. traefik.http.routers.myapp.rule=Host(`app.example.com`)
        │
        ▼
  Extract hostnames → filter by your DOMAIN
        │
        ▼
  Call Hostinger DNS API → upsert A records

On startup it does a full sync, then it listens to Docker events in real-time and re-syncs whenever a container starts or stops.

Prerequisites

Docker + Docker Compose
A domain on Hostinger with API access enabled
Your server's public IP reachable from the internet

Setup

1. Get your Hostinger API key

Log in to hPanel
Go to Profile → API Tokens
Create a new token with DNS read/write permissions

2. Clone & configure

git clone <this-repo>
cd hostinger-dns-sync
cp .env.example .env
nano .env   # fill in HOSTINGER_API_KEY and DOMAIN

3. Deploy

docker compose up -d

Check logs:

docker compose logs -f hostinger-dns-sync

Environment variables

Variable	Required	Default	Description
`HOSTINGER_API_KEY`	✅	—	API token from hPanel
`DOMAIN`	✅	—	Root domain, e.g. `example.com`
`PUBLIC_IP`	❌	auto-detected	Override server IP
`RECORD_TYPE`	❌	`A`	`A` (IPv4) or `AAAA` (IPv6)
`TTL`	❌	`3600`	DNS TTL in seconds
`DELETE_ORPHANS`	❌	`false`	Delete DNS records no longer in Traefik
`DRY_RUN`	❌	`false`	Preview changes without applying

Traefik label format

The service reads all containers with a label matching:

traefik.http.routers.<name>.rule=Host(`subdomain.example.com`)

Multi-host rules are supported:

traefik.http.routers.<name>.rule=Host(`a.example.com`) || Host(`b.example.com`)

Orphan cleanup

By default, the service only adds/updates records and never deletes them. Set DELETE_ORPHANS=true to automatically remove DNS records for subdomains that are no longer referenced by any Traefik router.

⚠️ Use with care if you manage other records manually on the same domain.

Test without making changes

DRY_RUN=true docker compose up hostinger-dns-sync

Security notes

The Docker socket is mounted read-only (:ro) — the container cannot start/stop containers.
The API key is passed via environment variable, never baked into the image.
Add .env to your .gitignore.