Materials in braced.io are losely coupled with Tekla Structures. Our Tekla component algorithm will pick materials with the same name. It doesn't mean that they have the same properties. That is the responsibility of the user.
In the Material Browser the user can create new materials and see the properties of the builtin materials.
Builtin database vs custom materials
There are several builtins: steel materials (S275, S355, ...), steel profiles (HEB, IPE, UPE, Pipes, Tubes, ...), bolts sizes (Metric, Imperial), etc.
Custom materials can be created but don't forget that calculations will be done with Eurocode 3.
A Tekla *.lis file can be uploaded and the cloud system will import compatible profiles, bolts and materials. Take a look here.