BioStack

BioStack is a healthcare data company in San Francisco, trading as BioStack Platforms, Inc. It sources clinical data from hospitals and turns it into datasets that companies use to train and evaluate medical AI models. It took part in Y Combinator's Spring 2026 batch and announced a $9.5 million seed round on 22 October 2026.

What it does

BioStack collects and structures healthcare data across electronic health records, laboratory results, imaging, ECGs, clinical notes, audio, treatments and patient outcomes, and links the events for each patient so that a model can follow the course of care. Its site describes four services: machine-learning-ready datasets, annotation of new or public data, reinforcement learning environments for post-training, and infrastructure for multi-agent reasoning. The company says its footprint covers more than 100 million de-identified patient records, several hundred thousand X-ray, MRI and CT scans and several million telehealth audio transcripts.

Who it serves

Its site names three kinds of customer: biotech startups that fine-tune and deploy models on custom data, AI labs that need domain-specific healthcare datasets and reward functions for training, and data companies looking for harder-to-find clinical data. The company says it works with hospitals in the United States, Brazil, India and Argentina. Its security and privacy controls are published through a trust centre linked from the site.

Key facts

Legal name: BioStack Platforms, Inc. Location: San Francisco, California, United States Chief executive: Sanat Mishra, co-founder Accelerator: Y Combinator, Spring 2026 Funding: $9.5 million seed, announced 22 October 2026 Investors named: Peak XV, Afore Capital, DCVC, Emerson Collective, SV Angel, Verdict Capital, Streamlined Ventures, Y Combinator Data types: health records, labs, imaging, ECGs, clinical notes, audio, treatments, outcomes