This can be a difficult decision. In your mind you want to build something that is exactly what you want, but you need to consider what the total cost of ownership will be for your application. We suggest evaluating whether or not an existing SaaS application has robust API support or if on-premise software has an open database.
It’s possible that with a good API set, you can add on the customizations you want or at least integrate with the other applications in your organization.
We have had success extending existing applications this way to create new functionality, while leveraging underlying value from a third-party application. We are happy to help you evaluate the right way to extract the maximum ROI from your options.