ModernBERT is a next-generation encoder model co-released by Answer.AI and LightOn. It is a comprehensive upgrade of the BERT model, offering longer sequence lengths, better downstream performance, and faster processing speeds. ModernBERT leverages the latest Transformer architecture improvements, with a strong focus on efficiency, trained on modern data scales and sources. As an encoder model, it excels in a variety of natural language processing tasks, particularly in code search and understanding. It is available in two model sizes: a base version (139M parameters) and a large version (395M parameters), suitable for diverse application needs.