goddns

Your IP address changes. Your DNS record does not. goddns fixes that.

It watches your public IP address and updates your DNS records whenever it changes — so your homelab, VPN, or self-hosted whatever stays reachable, even when your ISP decides to hand you a new address at 3am for no particular reason.

How it works

goddns is built around three concepts:

• Retrievers fetch your current public IP address (e.g. by asking your UniFi controller, or a public API like ifconfig.co)
• Providers push that IP to your DNS records (e.g. Hetzner Cloud DNS)
• Instances tie one retriever to one or more providers and run on a configurable interval

You can run multiple instances simultaneously — useful if you have several sites or networks whose IPs need to be tracked independently.

Configuration

Copy config.example.toml to config.toml and adjust to taste:

interval = "5m"

[retriever.home]
type = "ifconfigco"

[provider.my-provider]
type      = "hetzner_cloud"
api_token = "your-token-here"
zone      = "example.com"
rr_name   = "@"

[instance.homelab]
[instance.homelab.retriever]
name = "home"

[[instance.homelab.provider]]
name = "my-provider"

Provider and retriever parameters can be overridden per instance, so one provider definition can serve multiple zones:

[[instance.homelab.provider]]
name = "my-provider"

[[instance.homelab.provider]]
name    = "my-provider"
zone    = "another-zone.com"
rr_name = "subdomain"

See config.example.toml for the full reference and docs/PARAMETERS.md for all available parameters per plugin.

Running

The recommended way to run goddns is via Docker:

docker run -d \
  -v /path/to/config.toml:/config.toml \
  -e GODDNS_CONFIG=/config.toml \
  ghcr.io/tinyoverflow/goddns:latest

Images are published to the GitHub Container Registry for every release. Replace latest with a specific version tag for reproducible deployments.

Adding a plugin

Create a file in internal/plugins/, name it provider_<name>.go or retriever_<name>.go, implement the plugin.Provider or plugin.Retriever interface, and register it in init():

package plugins

import "goddns/internal/plugin"

type myConfig struct {
    Endpoint string `json:"endpoint" required:"true" doc:"API endpoint"`
}

func init() {
    plugin.RegisterProvider("my_provider", newFromConfig, myConfig{})
}

func newFromConfig(params map[string]any) (plugin.Provider, error) {
    cfg, err := plugin.Decode[myConfig](params)
    // ...
}

Run go generate to update the parameter documentation.

Building from source

go build ./cmd/goddns

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AI Disclaimer: This project used AI assistance (Claude by Anthropic) for architectural design decisions and to generate cmd/gendoc, the tool that produces the plugin parameter documentation.