Is working for a company that creates an application to connect pet owners with service providers and facilitate the buying and selling of pets through it forbidden in Sharia, and is the money earned from this work unlawful?

It is permissible to work for an application that connects pet owners with stores that provide services for them, if these animals are permissible to own and sell, such as birds and horses. This is because means take the ruling of their ends. Evidence for this is the permissibility of spending money on what entertains a child, and the permissibility of keeping a bird in a cage.

However, if the animals are impermissible to sell or own, such as dogs kept for boasting and companionship (and not hunting, guarding, or farming dogs), then it is not permissible to provide services for them. This is because it constitutes cooperation in sin. The price of a dog has been forbidden, and whoever keeps a dog not for hunting, livestock, or land will have a qirat or two qirats deducted from his reward every day.

If the application includes both types and cannot be restricted to what is permissible to buy and sell, then it is not permissible to create it.