How do we keep data synced up in real-time?

Hey everyone, I'm trying to figure out the best way to sync data in real-time across different services. It's mostly about user content that needs to show up everywhere right away. We looked into websockets, but keeping track of all those connections as things get bigger is becoming a real headache. Have you guys found any other approaches or tools that work well for keeping databases and caches updated across different locations with super low delay? I'm really interested in what the downsides are, too.