surprised no one's mentioned fairseq, which is probably the easiest way to train and use a transformer model. With huggingface etc you still have to write a bit

surprised no one's mentioned fairseq, which is probably the easiest way to train and use a transformer model. With huggingface etc you still have to write a bit of code for preprocessing input, training scheduling, batch inference and multi-gpu but fairseq has all that covered with built-in scripts.