creators

Jay Alammar — The Illustrated Transformer, Cohere

Jay Alammar wrote The Illustrated Transformer, is Director and Engineering Fellow at Cohere, and co-wrote O’Reilly’s Hands-On Large Language Models.

Jay Alammar is a machine learning educator and visual explainer best known for “The Illustrated Transformer” and “The Illustrated BERT, ELMo, and co.”, which take transformer language models apart in step-by-step diagrams; the posts are referenced in courses at MIT, Cornell, Stanford and Carnegie Mellon. He is Director and Engineering Fellow at Cohere, where he works on applied research into LLM code generation and code agents. With Maarten Grootendorst he wrote the O’Reilly book “Hands-On Large Language Models”, with more than 250 custom figures, and the two are writing a follow-up, “An Illustrated Guide to AI Agents”. He keynoted PyData Amsterdam in September 2026. He built Ecco, an open-source library for visualising transformer language models inside Jupyter notebooks. He has frozen his jalammar.github.io blog and now publishes on Substack as Language Models & Co.

Specialization

ML visualization, language models, NLP explainers, AI agents