Search Startups funded by Y Combinator (YC) 2026

Nessie is building personal AI brains that augment human cognition. Nessie turns your scattered AI conversations and documents into a shareable AI brain you actually own. It's a thinking partner that lets you instantly search your entire history of ideas, synthesize them into new insights, and watch your knowledge build on itself over time. Right now, your best thinking is trapped in ephemeral AI chat histories. Nessie unifies your context from ChatGPT, Claude, and (soon) Apple Notes/Google Docs/Notion/other context sources, auto-organizing the mess into an AI-enhanced brain. Next, we are unlocking sharing. Instead of sending a static doc, you will be able to send your "Product Strategy Brain" to a cofounder, or publish your "Research Brain" for your entire team to chat with. Who it's for: AI-native thinkers—founders, researchers, and writers—who believe their best ideas should compound. The Team: We are two Yale CS grads and former Amazon engineers building the tool we needed for ourselves. We combine Anna's obsession with neuroscience and augmenting human cognition with Tiger's lifelong passion for building products (he shipped an app with 70k+ users at age 13). Traction: Launched 3 weeks ago. We have over 1,200 users who have imported 300,000+ AI conversations into Nessie. 30% week-over-week organic user growth. Origin Story: Nessie was born after we hit the 1-million-token limit in multiple Gemini chats. Overnight, months of research disappeared. We realized the problem wasn't just about storage; it was that the medium for AI-native thought didn't exist yet. The chat window is a place to ask questions, not a place to build a mind. Our Vision: We are building a new medium for personal intelligence. Everyone will have an AI brain on Nessie. You will use it to think better, remember more, and share your mind with the world.

Serafis is building super-intelligence for financial markets. We mine petabytes of unstructured data to identify narrative inflections before they become consensus. Think building early conviction in Bitcoin (2014), Tesla (2018), or Nvidia (2022). We are already live with 12 organizations managing over $70B in capital.

We spend our lives in messaging apps. Slack. iMessage. WhatsApp. We face a constant stream of information, introductions, and things we need to do. What if you could bring together every message, from every platform, in a Superhuman-like experience, with AI agents that automatically complete your action items? That’s exactly what we’re building at Pally; a future where you never need to check another inbox again.

Morphik is open-source multimodal search for AI apps. We're used by customers ranging from space-tech teams searching across research papers to developers building brokerage agents.

Origami is an AI-powered spreadsheet to find and enrich your ideal customers. origami.chat has 100+ data sources - use it to find more of your perfect customers, enrich a CSV, or get decision makers. Try it out and get a lead list in seconds, start free → origami.chat Used by sales teams at CBRE, Clipboard Health, Remote.com, and more.

At Undermind, we're building a search engine that can handle extremely complex questions. It’s geared at experts, like research scientists and doctors, who need to find very specific resources to solve high-stakes problems. We’ve rebuilt search from the ground up to address this. Our new approach employs high-quality LLMs to adaptively explore a database, mimicking how a human researcher carefully discovers information. This approach dramatically outperforms (by 10-50x) traditional keyword search and other modern AI-based retrieval methods. Our first target users are the 50 million researchers searching for scientific literature on PubMed and Google Scholar every month. We’ve have paying users across fields like medicine, ML, biotech, finance, and more.

Onyx is the open source chat UI connected to your company’s docs, apps, and people. We ingest and sync from all sources of information (Google Drive, Slack, GitHub, Confluence, Salesforce, etc.) to provide a centralized place for users to ask about anything. Imagine your most knowledgeable co-workers, all-rolled into one, and available 24/7! Check us out on Github: https://www.github.com/onyx-dot-app/onyx Or visit our website: https://www.onyx.app/

Reducto offers robust and reliable document ingestion for any workflow. Our API allows you to convert complex, unstructured documents into structured outputs that are perfect for RAG, process automation, and more.

Webhound builds long-horizon AI research agents that scale quality with time and budget. Our agents can create either structured datasets or fully cited research reports.

Waldium is an AI-driven platform for researching, writing, and publishing technical knowledge in formats that both humans and AIs can understand. We help developers create technical guides, resources and tutorials — structured, durable knowledge that AIs can learn from, cite, and build upon.

Artemis Search is a vector database search with a twist. We use special-purpose deep-learning models instead of using textual / semantic similarity to evaluate how good a search result is. This enables us to actually reason how well search results match the intent of the search query, eliminating the problems that come from evaluating search results on how much they look like the search query.

Connect your data. Train your models. Query text, user or session context and retrieve relevant results in milliseconds. Explore our case studies to see how we’ve helped leading brands drive significant engagement and revenue: https://www.shaped.ai/case-study.

Instead of just links, Andi AI gives you answers - like chatting with a smart friend. Andi is a new type of search engine that uses generative AI and language models combined with live data to generate factually correct answers to questions, and to explain and summarize information combined from the best sources. Andi works as a search chatbot that's ad-free and privacy-focused. Ask Andi to... ✅ Answer questions 🧠 Find, summarize and explain information 🔍 Navigate and search the web Search is broken because of SEO spam, ads, and surveillance capitalism. Andi cuts through the clutter to get you straight to the knowledge you need. It presents results visually in a way that's easy to understand with a simple chat interface, and protects you from ad tech and distraction. You can try the search app at https://andisearch.com

Exa is a search engine built for AIs. We enable developers to filter the internet's content with complex queries in order to bring the world's knowledge into their AI apps.

Infrastructure for search teams building retrieval and RAG. Trieve combines search language models with tools for tuning ranking and relevance. Building excellent search is difficult and can take months to implement then even more time to maintain. Trieve offers production-ready infrastructure that works out of the box to help search teams build adjustable AI search and RAG into their products. With tools for custom models, relevancy weighting, date-recency biasing, semantic full-text hybrid search, recommendations, and more Trieve covers the full spectrum of what a team wants from their discovery infrastructure.