Begin by outlining the specific needs of your app. Consider the type of application you're building, its complexity, the expected load, and the real-time data processing requirements.

Security is paramount, especially for applications handling sensitive data. Evaluate the built-in security features of the backend technologies, their known vulnerabilities, and how they are addressed by the community or vendors.

Your chosen technology should be able to handle growth in terms of users, data, and transaction volumes without significant rework. Research how well different backend technologies scale and their performance benchmarks under various conditions.

Ensure the backend technology is compatible with the other components of your tech stack, including the frontend technologies, database systems, and any third-party services or APIs you plan to integrate.

Some technologies offer faster development cycles due to their frameworks, libraries, and tools that simplify common tasks. Consider the ecosystem surrounding the technology, including community support, availability of talent, and the richness of resources and libraries.

Finally, consider the total cost of ownership, including licensing fees (if any), development costs, hosting expenses, and maintenance. Open-source technologies might reduce upfront costs but consider the expertise required and the potential need for commercial support.

The technology you choose should be well-supported and regularly updated. Look into the community and vendor support for the technology, its update history, and the availability of developers skilled in the technology.