You are looking for a cheaper alternative to Bangkirai but still want a solid and stable wood species? Then Kapur might be the solution to your problem. Because it is in durability class II, it is already classified as a durable hardwood species.
Kapur originates from the tropical regions of Southeast Asia and has a beautiful color that can range from light reddish brown to dark reddish brown. It is also quite stable, which makes this tropical hardwood easy to work with. Because of this, pre-drilling is also recommended.
Kapur is usually used indoors, but can certainly also serve as a decking board. Make sure that you use rust-free materials for fastening, otherwise your wood will give black spots due to the tannic acid present.