OpenWRT allows you to choose from a list of providers and configure DDNS pretty quickly. Router periodically checks your WAN IP, compares it to the A-record for the DDNS domain and updates it if necessary. The update happens via URL with a few parameters in it. However, at this moment DDNS option cannot be enabled for my domain that I have with Canadian OVH branch. The option is missing in the online graphical interface and API says that it is not available. However, with access to REST API it’s possible to work around this limitation.