Founded in 2005 by Paul Graham, Jessica Livingston, Robert Morris and Trevor Blackwell and led today by president and CEO Garry Tan, Y Combinator is the template every other accelerator copies: two three-month batches a year in San Francisco, a standardised $500,000 deal, and a Demo Day that functions as the seed market's clearing house. Its AI position is unusual among investors — rather than concentrating capital in a handful of frontier labs, YC underwrites AI as a volume business, funding hundreds of application-layer and developer-tooling teams per year and letting the market select the winners. Since 2023 the large majority of each batch has described itself as AI-native, making YC the single widest funnel into early-stage AI.
YC does not try to pick the one model company that wins. It writes the same cheque into hundreds of teams per year, accepts a high failure rate, and relies on batch scale plus follow-on rights to capture outliers — the opposite of the concentrated frontier bets made by growth funds.
Frontier training runs are far outside a $500K cheque. The portfolio clusters instead around products built on top of someone else's model: voice agents, coding tools, vertical copilots, and enterprise search where a small team can reach revenue inside a batch.
Speech, evaluation, memory and fine-tuning infrastructure recur batch after batch — Deepgram, AssemblyAI, Vellum, OpenPipe and Mem0 all sell picks and shovels to other AI builders, a category YC has funded for a decade.
The uniform deal and Demo Day remove price negotiation from the earliest stage. For founders the value is access to 1,000+ investors on a fixed date; for YC it is the ability to originate at scale without competing on valuation.
A selection of YC-backed AI companies, from autonomy and data labelling to the voice, memory and evaluation tooling layers.
Data labelling and evaluation infrastructure for frontier labs and defence programmes; YC S16.
Self-driving vehicle developer acquired by General Motors; the batch's earliest large autonomy outcome. YC W14.
Speech-to-text and voice agent APIs sold to contact centres and voice product teams. YC W16.
Speech recognition and audio intelligence models delivered as a developer API. YC S17.
Contract lifecycle platform that added model-driven review and redlining to legal workflows. YC W15.
AI language tutor using speech models for open-ended conversation practice. YC S16.
Developer platform for building and deploying real-time voice agents.
Voice agent infrastructure for inbound and outbound phone operations.
Prompt management, evaluation and deployment tooling for LLM applications.
Fine-tuning and distillation platform that converts prompt traffic into cheaper task-specific models.
Open-source memory layer giving agents persistent, retrievable user context.
Open-source enterprise search and chat over internal company knowledge; formerly Danswer.
The pre-AI outcomes that made the batch model credible — not exhaustive, but the alumni most often cited by founders applying today.
Home-sharing marketplace; YC W09 and the accelerator's defining outcome.
Payments infrastructure for internet businesses. YC S09.
Listed cryptocurrency exchange. YC S12.
Local delivery marketplace. YC S13.
Grocery delivery and retail media platform. YC S12.
File sync and storage. YC S07.
Social discussion network funded in YC's first batch in 2005.
Live-streaming platform, launched out of Justin.tv. YC S07.
No rounds led by Y Combinator are in the tracker yet. Deals will appear here as they are recorded.