ESM3-open

ESM3 is the flagship of EvolutionaryScale, the biology AI lab founded by the former Meta ESM team, launched in June 2024. It departs from the encoder-only ESM-1/ESM-2 line: a masked generative transformer that represents a protein across three simultaneous tracks — amino-acid sequence, discrete structure tokens, and function annotation — so a single model can be prompted with any combination of partial sequence, structure and function and asked to complete the rest. Trained on 2.78 billion proteins, it famously generated a novel green fluorescent protein that the team estimates would take 500 million years of natural evolution to arise.

The open release, esm3_sm_open_v1 (1.4B parameters), is free for non-commercial scientific use under the Cambrian Open License; the 7B and 98B flagships are served through the Forge API. The underlying science is published in Hayes et al., Science 2025. For academic protein-design work it is the most capable openly downloadable generative biology model, though commercial teams need the paid Forge tier.

• No standard benchmark table; Science 2025 paper (Hayes et al.) reports generative design results including novel GFP generation (peer-reviewed, provider-run)