Independent benchmarking — Nature Biomedical Engineering 2025 across 19 models and 31 tasks, and Nature Communications 2026 across 32 models — found no single winner: CONCH and Virchow2 lead on average at AUROC 0.71, with tissue-specific strengths, and ensembling two or three encoders beats any one. Several of the strongest models are released under non-commercial terms, which we check against your intended use before building. Tiers and rates read as above; use them for initial sizing only.
H-optimus-0
Vendor: Bioptimus, with Aignostics, Mayo and Charité collaborators
What it does: is a 1.1B tile encoder that led pan-cancer performance in one independent benchmark, and is Apache-licensed for the weights — an unusual combination in this category.
Best pan-cancer performance in one independent benchmark; AUROC 0.68 mean across 31 tasks in another.
H-optimus-1
Vendor: Bioptimus
What it does: is the newer version of the same encoder, for classification, grading, retrieval and prognosis work.
Task-dependent across classification, grading, retrieval, prognosis and slide-level benchmarks.
UNI
Vendor: Harvard Medical School (Mahmood lab)
What it does: is the widely cited Harvard tile encoder, strong on brain, bladder, breast and pan-cancer tasks. Gated and non-commercial, which is the constraint to check before it becomes your base layer.
Strong on brain, bladder, breast and pan-cancer tasks; AUROC 0.68 mean across 31 independent tasks. CC-BY-NC-ND, gated.
Virchow
Vendor: Paige AI, with Microsoft
What it does: is the first-generation Paige encoder, trained on a very large clinical archive and joint-best overall in independent benchmarking.
Joint-best overall in independent benchmarking, AUROC 0.71 across 31 tasks; leads on colon and prostate.
Hibou-B
Vendor: HistAI
What it does: is the Apache-licensed member of the modern encoder set — nearly the accuracy of the gated models with none of the licence friction, which often decides the choice.
AUROC 0.67 mean across 31 independent tasks; Apache-licensed, which is rare in this category.
Hibou-L
Vendor: HistAI
What it does: is the larger Hibou encoder, at similar benchmark accuracy and a non-commercial licence.
AUROC 0.67 mean across 31 independent tasks (CC-BY-NC for the L variant).
Phikon
Vendor: Owkin
What it does: is the small, fast Owkin encoder: a few points behind the leaders and cheap enough to run across a whole archive.
AUROC 0.65 mean across 31 independent tasks; small and fast.
EXAONEPath
Vendor: LG AI Research
What it does: is among the top encoders for brain tissue tasks specifically, which is the case for it over a general leader.
Among top models for brain tissue tasks (independent). Non-commercial.
Path Foundation
Vendor: Google Research
What it does: produces patch embeddings that linear probes turn into tumour detection or grading with small label budgets. Superseded by MedSigLIP, and listed here for continuity.
Efficient linear probes for tumour detection and grading with small label budgets (developer-reported). Legacy model — MedSigLIP is the current recommendation.
REMEDIS-Pathology
Vendor: Google Research
What it does: is a Google pathology representation model for classification, grading and retrieval from patch embeddings.
Task-dependent across classification, grading, retrieval and prognosis benchmarks.
Kaiko
Vendor: Kaiko
What it does: is an openly published tile encoder for pathology classification and retrieval work.
Task-dependent across pathology benchmarks.
Lunit-BT
Vendor: Lunit
What it does: is one of four Lunit encoders trained with different self-supervised objectives, which makes the set useful for ensembling rather than picking one.
Task-dependent across pathology benchmarks.
Lunit-DINO
Vendor: Lunit
What it does: is the DINO-trained member of the Lunit set, for patch embeddings and downstream prediction.
Task-dependent across pathology benchmarks.
Lunit-MoCoV2
Vendor: Lunit
What it does: is the MoCo v2 member of the Lunit set.
Task-dependent across pathology benchmarks.
Lunit-SwAV
Vendor: Lunit
What it does: is the SwAV member of the Lunit set.
Task-dependent across pathology benchmarks.
CTransPath
Vendor: Sichuan University / Tencent AI Lab
What it does: is a long-established pathology encoder, still a solid retrieval baseline and light to run.
Task-dependent across pathology classification and retrieval benchmarks.
RetCCL
Vendor: Sichuan University / Tencent AI Lab
What it does: is built for retrieval specifically — finding visually comparable regions across an archive rather than labelling them.
Task-dependent across pathology retrieval benchmarks.
PathoDuet
Vendor: Shanghai Jiao Tong University
What it does: is a pathology encoder for patch-level classification and downstream prediction.
Task-dependent across pathology benchmarks.
BEPH
Vendor: Shanghai Jiao Tong University
What it does: produces patch embeddings for classification, grading and prognosis work.
Task-dependent across pathology benchmarks.
PathOrchestra
Vendor: Shanghai AI Lab
What it does: covers a wide set of pathology tasks from one model, which reduces the number of encoders a pipeline has to maintain.
Task-dependent across pathology benchmarks.
GPFM
Vendor: Smart Lab / HKUST collaborators
What it does: is a general pathology foundation model covering patch and slide-level prediction.
Task-dependent across pathology benchmarks.
HIPT
Vendor: Mahmood Lab
What it does: works up a hierarchy from patch to region to slide, which is how it reaches slide-level prediction without a separate aggregator.
Task-dependent across classification, grading and prognosis benchmarks.