In some ways, HTTP 3 is the same HTTP messages, just over QUIC.
But as you get into other features, there are differences. And your clients and servers need to both have fallbacks to HTTP 2, since UDP connectivity might not be available, and fallback is expected.
So, you have to build support for having working push, or not. Or having working priorities, or not. Or having long-lived non-HTTP sockets, or using fallbacks like web sockets or even long polling. There’s even more fun on the horizon, and I’m not looking forward to my colleagues thinking of a fallback strategy for some of those...
But as you get into other features, there are differences. And your clients and servers need to both have fallbacks to HTTP 2, since UDP connectivity might not be available, and fallback is expected.
So, you have to build support for having working push, or not. Or having working priorities, or not. Or having long-lived non-HTTP sockets, or using fallbacks like web sockets or even long polling. There’s even more fun on the horizon, and I’m not looking forward to my colleagues thinking of a fallback strategy for some of those...