# Protein design guides

> Guides on de novo protein and antibody design, inverse folding, and developability screening.

- [AlphaFold license and commercial use](https://proteiniq.io/guides/alphafold-license-commercial-use): AlphaFold 2 and the AlphaFold Database allow commercial use, while the AlphaFold 3 weights and AlphaFold Server do not. See what each license allows and which models, including Boltz-2, Chai-1, RFdiffusion and ESM, companies can use.
- [What is antibody engineering?](https://proteiniq.io/guides/what-is-antibody-engineering): Antibody engineering changes an antibody's sequence or structure to improve binding, reduce immunogenicity, tune effector function or create new formats. Learn the core techniques and computational workflows.
- [ipSAE explained](https://proteiniq.io/guides/ipsae): ipSAE is an interface confidence score for AlphaFold2, AlphaFold3 and Boltz that ignores disordered tails. Learn how it is calculated, why it beats ipTM and what 0.6 to 0.8 mean.
- [What is Chai-2? De novo antibody design explained](https://proteiniq.io/guides/what-is-chai-2): Understand what Chai-2 designs, what its experimental hit rates mean, how access works, and which open tools address related antibody and protein binder tasks.