ESM C / ESMFold2 (esm package)
Newer ESM protein world-model family with folding, now MIT licensed.
Developer: EvolutionaryScale / Chan Zuckerberg Biohub
Overview
- Developer
- EvolutionaryScale / Chan Zuckerberg Biohub
- Category
- Protein language models
- Commercial rights
- Commercial OK
- Commercial cost
- Free commercially
- Compute
- Heavy GPU
- Open weights
- Yes
- Last verified
Capabilities
Newer ESM encoder family (ESM C). Input: a protein sequence; output: embeddings and likelihoods at better quality-per-parameter than ESM-2, as a drop-in replacement for representation and scoring workloads.
When to use it
Use for the strongest open ESM-family embeddings/folding where license matters. Large weight downloads and newer API; older ESM3 checkpoints may still carry different terms.
Input / Output
- Input
- a protein sequence
- Output
- embeddings and likelihoods at better quality-per-parameter than ESM-2, as a drop-in replacement for representation and scoring workloads
Compute
Heavy GPU. Other tools with this compute profile →
Commercial Licensing
Commercial rights — may a company use it?
Commercial use OKLicence as writtenMIT License
LICENSE.md in the repo is MIT (Copyright 2026 Chan Zuckerberg Biohub) and the README's Licenses section states the models are available under the MIT license. Note this differs from the earlier ESM3 non-commercial community license; verify the checkpoint you actually download.
The licence read at the source allows use by a company. Attribution or copyleft conditions may still apply — read the note.
Commercial cost — is commercial use free of charge?
Free for commercial useFree: the esm repository's licence file is MIT (Copyright 2026 Chan Zuckerberg Biohub) and the open checkpoints are downloadable without payment. The maintainers also sell hosted API access to the larger models, which is optional.
Price and rights are separate: this panel is about money, the panel above is about permission.
- Commercial OK ≠ Free of charge. A tool can be licensed for company use and still need a paid licence for a dependency (BindCraft → PyRosetta).
- Free download ≠ Commercially licensed. Weights you can download at no cost may still forbid commercial use (AlphaFold 3).
- Unverified ≠ Commercially permitted. If no published statement settles it, treat it as unknown — not as a yes.
- Every component counts. Each status considers the code licence, the model-weights terms, required dependencies and any terms of use.
Model Weights
Open weights. A separate weights licence is Not documented as its own field; where weights carry different terms from the code, that is stated in the licence explanation above.
Dependencies
Not documented as a separate field. Any dependency that affects commercial use (for example a paid PyRosetta licence) is named in the licence and cost explanations above.
Official References
- Official site / repo
- github.com/evolutionaryscale/esm
From the makers of FoldScout
From AI Design to Wet-Lab Validation
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