The 2017 neural network architecture, built around self-attention, that replaced recurrent networks for sequence modeling and became the substrate of every large language model since.
The transformer is a neural network architecture introduced in the 2017 paper "Attention Is All You Need" by Vaswani and colleagues at Google Brain. Its distinguishing mechanism — self-attention — allows each position in a sequence to weight its relationship to every other position directly, replacing the sequential processing of earlier recurrent neural networks. Every major LLM of the current era (GPT, Claude, Gemini, LLaMA) is a transformer variant.
Transformer Architecture
In The You On AI Field Guide
The transformer is the enabling technical precondition of the You On AI Cycle's subject matter. The jump from pre-2017 language models (recurrent, slower to train, shorter-context) to post-2017 (transformer-based, parallelizable, scalable to internet-sized corpora) was what made the current LLM era possible.