Boltz-2
Family overview — summarizes releases; licenses and availability belong to each release.
Maintained by Boltz (Boltz PBC)671
Boltz-2 is a biomolecular foundation model that predicts the 3D structures of complexes of proteins, nucleic acids, and small molecules together with protein-ligand binding affinity. It was released in June 2025 by the Boltz team at MIT Jameel Clinic with Recursion and is now presented by Boltz PBC as one of its open-source models. It ships as a structure and confidence checkpoint plus a separate affinity checkpoint.463
- Repository: GitHub repository (jwohlwend/boltz) (external site: github.com)
- Model hub: Boltz-2 checkpoints (Hugging Face) (external site: huggingface.co)
- License: LICENSE (MIT) (external site: github.com)
- Release notes: Boltz-2 announcement (external site: boltz.com)
- Paper: Boltz-2 technical report (bioRxiv, doi:10.1101/2025.06.14.659707) (external site: doi.org)
Releases assessed
| Release | Weights | Tier (USASI rubric v0.2) | License | Released |
|---|---|---|---|---|
| Boltz-2 (boltz2_conf and boltz2_aff checkpoints) | Weights: Public | Model-disclosure tier (USASI rubric v0.2): Open-weight | MIT | Jun 6, 2025 |
What it is useful for
The README describes structure prediction from YAML inputs and two affinity outputs: a binder probability intended for separating binders from decoys in hit discovery, and an affinity value intended for comparing related binders during hit-to-lead and lead optimization. The announcement adds contact constraints, template guidance, and method-conditioning options.14
Organization context
U.S. eligibility
Eligible · basis: U.S.-governed project
Boltz-2 was developed by the Boltz team at MIT Jameel Clinic with Recursion, and Boltz PBC, whose terms give a Massachusetts notice address, now presents it as one of its open-source models and links the repository from its website. The technical report also lists authors at Valence Labs and ETH Zurich. The code repository sits under an individual developer's GitHub account, and its license names three individual copyright holders.46825
Sources
This listing is not an endorsement, a safety assessment, or a federal approval.