[yftsui]

The microchip stores nothing but a serial number. I don’t quite understand the design that you would need a vendor to maintain a database between the serial and owner information, why not just store owner phone number like a traditional dog tag?

[burnt-resistor]

It's a permanent primary key into "an" owner database. Unfortunately, there are 40+ databases as there are that many registration companies. I don't even know if there's a unified interface to query all of them simultaneously. Does anyone know how the queries work if a pet be registered in some small or obscure registry that's not supported by every shelter/agency?

[gizmo686]

Dog tags are easy to replace. Microchips are not. Having a level of indirection allows the meaningful contact information to be updated as needed.

[sigwinch]

You don't want the chip to be reprogrammable or wipeable.