In countries such as England, Canada and the USA, one can buy ready-made artificial nests, nesting platforms and bird feeders for various species of birds.

There are also online on various sites and patterns to make your own.

For example at the link https://wdfw.wa.gov/species-habitats/living/woodworking-projects you can find the pattern of an illustrative wooden barn swallow nest platform.

This particular platform can also be used as a robin nest platform.