APIs Startups funded by Y Combinator (YC) 2026

AI teams spend 6+ months building document workflows, yet fewer than 10% ever reach production. Generic LLM parsers and OCR collapse on multimodal documents with text, tables, images, and charts. Poor parsing and suboptimal chunking cripple RAG pipelines and downstream automation. Unsiloed AI has built state-of-the-art vision models which serves as the infrastructure layer for turning unstructured data into structured, queryable, and LLM-ready assets. Our APIs are already parsing hundreds of thousands of documents for startups and NASDAQ-listed enterprises, powering vertical AI solutions across industries. On public benchmarks, Unsiloed AI consistently outperforms solutions from LlamaIndex, Gemini, Mistral, and Unstructured.io among others.

sieve solves data cleaning for hedge funds and investment firms by letting them get clean data in four lines of code. Currently, their data pipelines have conditions that raise for human review, which literally send an email to engineers with data that needs to be reviewed. We provide an API that integrates directly into their existing pipeline - instead of raising for human review, they can send all the same information to our API and get clean, high-quality data back. By using our AI agents built specifically for financial data collection, along with expert-in-the-loop review, we provide our clients with clean, validated data at a scale and level of quality that wasn't achievable before.

Miden is building a modern infrastructure that facilitates the launch of card programs and various financial products for businesses in Sub-Sahran Africa. Just by reducing integration time, card fraud, improving stability, and being customer focused we quickly rose to top 5 in TPV among card issuing Fintechs in Sub-Saharan Africa within 8 months of launch. We’re going to build the first comprehensive fintech and banking software stack for Africa, based on modern technology. We’re starting with a card issuer-processor.

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.

Documents are everywhere. Through all industries, understanding their content is a critical step of many processes that software builders throughout the globe want to automate. We focus on the science, the AI, the deep learning to give these builders the one API they need to automate the understanding of documents and give their software human-like superpowers. Based on three pillars: - A product: a universal self-service platform where builders can train their own models - A catalog of use-cases: We push critical use cases to the limits of human performances in critical markets such as Accounting software, AP Automation, Expense Management, KYC and many others - A internal capability to make tailor-made AI: We answer to specific needs from large customers that needs a custom AI of their own to handle their use cases

Waypoint combines a modern email API with a visual template builder so teams can ship faster. Alternative to SendGrid, MailGun, or Postmark.

Natural Language for the Internet of Things. Wit.ai is an API that makes it easy for developers to build applications and devices that you can talk to. Any app, any device can use Wit.ai to take natural language input (speech or text message) from users and turn it into a command. Wit.ai is a Y Combinator company based in Palo Alto, and funded by Andreessen Horowitz.

Kimono Labs lets people turn websites into structured APIs from their browsers in seconds. We are based in San Francisco, California and graduated from the Y Combinator startup accelerator. Our main product, a bookmarklet or chrome extension, enables users to scrape and crawl websites without any programming required.