Chai Discovery vs Nabla Bio (2026)
This is a close comparison, and Nabla Bio makes it directly: its own technical report benchmarks JAM against Chai Discovery's published results target by target, and names a target where Chai did better. Both design antibodies and miniproteins from a target and an epitope. The difference is how you reach the model. Chai licenses its foundation models to research organizations as a product, with three published generations, and released its structure model, Chai-1, with open weights. Nabla uses JAM inside its own discovery collaborations rather than handing it over, and concentrates on the membrane protein class, publishing its results with the targets it missed stated alongside the ones it hit. Chai is the one for a team that wants to run a published, improving model itself across many targets. Nabla is the one for a partnership on a hard membrane target where the platform does the designing.
- Foundation models licensed as a product, with three published generations and an open weights structure model.
- A fit for a team that wants to design across many targets itself rather than hand a target to a partner.
- Published design results across dozens of antigens, with monoclonal and VHH formats and species cross reactivity.
- De novo design delivered inside a discovery collaboration rather than as self serve software.
- A focus on multipass membrane proteins, with results published target by target.
- A technical report that benchmarks against a named competitor and states where it lost.
This comparison is published by AI Health Index, an independent research platform that compares healthcare AI vendors objectively. Chai Discovery and Nabla Bio are each graded against the same capability taxonomy, from each vendor's own public materials and the regulatory record, under the AI Health Index verification standard. No vendor pays for placement, and no vendor has reviewed this page. How this evidence is graded
Plain facts
| Fact | Chai Discovery | Nabla Bio |
|---|---|---|
| Primary category | Drug Discovery AI | Drug Discovery AI |
| Founded | 2024 | 2021 |
| Headquarters | San Francisco, California | Cambridge, Massachusetts, United States |
| Website | chaidiscovery.com | nabla.bio |
Side by Side
Each record in one paragraph
Written to be quoted whole. Each paragraph states what the AI Health Index verified about the vendor, with the caveats attached. Generated from this pair’s live capability grades, so it moves when a grade moves.
The AI Health Index awards Chai Discovery its top capability grade on AI Centrality, AI Governance and Bias Disclosure and Setting and Specialty Coverage. Set against Nabla Bio, Chai Discovery grades higher on AI Safety and PHI Stewardship, HIPAA and BAA Posture and Setting and Specialty Coverage. Its thinnest published disclosure sits on Security Certifications and Trust Center and EHR and Interoperability Depth. Grades reflect evidence the AI Health Index could verify at the last review, so a low grade records disclosure the vendor has not published rather than a capability it has been shown to lack.
Source: AI Health Index, October 2026
The AI Health Index awards Nabla Bio its top capability grade on AI Centrality and AI Governance and Bias Disclosure. Set against Chai Discovery, Nabla Bio does not grade higher on any scored axis, though the two are level on several axes, including AI Centrality, Autonomy and Oversight Model and Model and Technology Transparency. Its thinnest published disclosure sits on several axes, including AI Safety and PHI Stewardship, HIPAA and BAA Posture and Security Certifications and Trust Center. Grades reflect evidence the AI Health Index could verify at the last review, so a low grade records disclosure the vendor has not published rather than a capability it has been shown to lack.
Source: AI Health Index, October 2026
Questions buyers ask
Should we choose Chai Discovery or Nabla Bio?
The AI Health Index grades Chai Discovery higher than Nabla Bio on every axis that separates them, AI Safety and PHI Stewardship, HIPAA and BAA Posture and Setting and Specialty Coverage. Nabla Bio does not grade higher on any scored axis.
Where do Chai Discovery and Nabla Bio differ most?
The widest separation the AI Health Index records between Chai Discovery and Nabla Bio is on AI Safety and PHI Stewardship, where Chai Discovery grades C and Nabla Bio grades D. That axis sits in the AI Capability group, so it should carry the most weight for a buyer whose binding constraint is how much of the work the model itself is trusted to do.
Where do Chai Discovery and Nabla Bio grade the same?
The AI Health Index grades Chai Discovery and Nabla Bio the same on several axes, including AI Centrality, Autonomy and Oversight Model and Model and Technology Transparency. Neither holds an advantage the index can evidence on those axes, so they should not carry weight in a selection between these two.
What have Chai Discovery and Nabla Bio not disclosed?
At the last review, at least one of Chai Discovery and Nabla Bio published thin or absent detail on several axes, including AI Safety and PHI Stewardship, HIPAA and BAA Posture and Security Certifications and Trust Center. The AI Health Index treats an absent disclosure as a gap in the public record rather than a failure of the product, so these are the axes to get in writing during diligence instead of inferring from the grade.
Related comparisons
Other published head to head assessments involving these vendors or their closest peers. The full set for this category is on the Drug Discovery AI page.
Both records were reviewed in October 2026. Neither publishes a price; Chai sells model access through agreements and Nabla works through discovery collaborations.
Ask both for design success rates on targets like yours with the denominators attached, and how each handles the targets where the model comes up empty.