The main advantage of custom software is that, unlike with off-the-shelf solutions, it is possible to immediately provide for potential future scaling and integration with external products and services. In order to make use of this advantage, however, one needs to give special consideration to the planning stage.
Once the project plan is approved, altering it gets more difficult. Therefore, we recommend prioritizing such aspects as easily extendable functionalities, database infrastructures, load balancing, end-to-end documentation, and potential failures.