Text generation web UI now has an API similar to openAI that you can easily access with your own GUI. llama.cpp also has a server component, just like koboldcpp. For an easy start, I would recommend oobabooga (Text generation web UI). This does provide its own GUI, but you don't have to use it (and it can now be switched off using an argument --nowebui). Their API is really great. The advantage is that you don't have to worry about things like different formats, chat templates etc. yourself. Also, it is compatible with many backends, such as lllama.cpp, exllama, exllamav2 etc. Otherwise, koboldcpp is also a simple backend that is easy to set up.
Text generation web UI now has an API similar to openAI that you can easily access with your own GUI. llama.cpp also has a server component, just like koboldcpp. For an easy start, I would recommend oobabooga (Text generation web UI). This does provide its own GUI, but you don't have to use it (and it can now be switched off using an argument --nowebui). Their API is really great. The advantage is that you don't have to worry about things like different formats, chat templates etc. yourself. Also, it is compatible with many backends, such as lllama.cpp, exllama, exllamav2 etc. Otherwise, koboldcpp is also a simple backend that is easy to set up.