Middleware is the technological foundation for enterprise application integration. You can implement middleware to connect your legacy apps to your modern apps, your modern apps to each other, and anything to everything else. You can also optimize how your data is stored and retrieved or improve the ways you develop apps.
Here’s an example: Let’s say you want your applications to act on streams of data in real-time, rather than acting on historical data? Apache Kafka is open source middleware that can do that.