Y Combinator

Build with the power of code, visually

The financial stack for growing companies

AI-powered language learning through real conversation

The data platform powering the AI economy

The open-source product analytics platform

Global payroll and compliance for remote teams

See how food affects your blood sugar in real time

Incredibly fast JavaScript runtime and toolkit

Email for developers, done right

Build internal tools remarkably fast

Run AI models with a cloud API

Build full-stack web apps by describing them in natural language

Deploy instantly, scale infinitely, sleep soundly

Buy a home by taking over a 2-3% mortgage from a seller

Code, collaborate, and deploy from your browser

Web scraping API built for LLMs

Open-source link management for modern teams

Payments infrastructure for Africa

2x faster GitHub Actions with zero config changes

Beautiful documentation that writes itself

AI that reads your entire codebase to catch bugs

The modern accounts receivable platform for B2B

Launch a mobile service that runs itself

ComfyUI for everyone on your team

The TypeScript framework for building AI agents

First Buy Now Pay Later solution for Commercial Rent

Win local search on ChatGPT and other LLMs

Real-time AI generation for creative professionals

AI-native commercial insurance brokerage

AI Infrastructure for America's Empty Truck Space

Business banking built for internet entrepreneurs

Cursor for Designers

Making next-generation antibiotics that outpace bacterial evolution

The Agent Analytics Platform

Medical Record Retrieval with Zero Human Error

Voice AI infrastructure for developers

Datadog for industrial robots

Neural search API designed for AI applications

AI code reviews and bug fixes

Helping America's businesses become employee owned

Hardware for Electric Vehicles.

The platform for enterprise AI agent automations

Payroll, benefits, state compliance for startups

Open source LLM engineering platform

Build and operate underwater data centers

Open source API development ecosystem

The fastest way to launch product catalogs

AI agent for Accounts Receivable

Email for modern SaaS companies

More alpha, less latency: exchange and HFT on one chip.

Customer Context for Agents

Reusable Satellites for zero-g manufacturing

Audio intelligence API for developers

AI agents you can rely on

AI loan origination that lets banks process 10x more

Analytics built for Growth

AI Agents for Distributors

Secure code execution sandboxes for AI agents

Foundation models to automate x-ray analysis for radiologists

AI engineering scientists - search PLMs, read drawings, run simulations.

AI tutors for exam prep

AI video repurposing for short-form content

Converting biology into digital molecular maps

Automatic audit trails for PostgreSQL without code changes

Autonomous Electrical Engineering

Open-source customer support platform

A foundation model for physics.

AI-enabled procurement for government

Open source CRM built for modern teams

Open source LLM observability for production AI

Inference for real-time agents

Open source framework for multi-modal AI agents

Authentication for AI Agents

The organic growth engine for financial advisors

AI agents and unified data layer for revenue teams

An AI teammate that automatically updates customer docs

Character.AI with real time video avatars

AI commercial lease abstractions and review

Open source low-code platform for internal tools

Open-source background jobs for modern TypeScript apps

Claude Code plugin that reduces token consumption and cost by 50%

AI Agents to scale AML, KYB and KYC operations

Universal secrets manager for teams

AI gateway and LLMOps platform for production

Data for reasoning agents in dynamic environments

AI Sales Teams for Dental Practices

AI-native operating system for behavioral health

Leading open-source web agent project with 50k stars in 3 months

Open source DocuSign alternative for document signing

Open source full-stack web framework for React and Node

Reactive Python notebooks you can deploy as apps

Building an AI financial infrastructure company

Build, test, and deploy voice AI agents

GenAI Interactive story. Creator write fictions 10x faster.

Voice AI for medical language translation

Making droughts end

Open-source observability — logs, metrics, traces

Open-source LLM observability with OpenTelemetry

Reliable AI for Regulated Ops

Agent with a computer

AI for insurance verification and billing at dental clinics

Open-source secret management platform

Browser extension and proxy for API mocking and testing

Open source full-stack monitoring and error tracking

AI physical therapy for athletes

Simulation software for battery and automotive companies

AI for SOX testing

Beautiful, interactive API documentation

One-click bug reports that developers actually love

Interactive email builder for ecommerce brands

Cloud cost estimates in pull requests

Autonomous project management with built-in AI

Most powerful coding agent for Android engineers

A launcher that turns Minecraft into a game platform

Robinhood for sports prediction markets

Open source billing and metering for usage-based pricing

AI-native security engineering for mission critical codebases

Serverless infrastructure for AI and ML workloads

Replace the humans fixing bad data

LLM-first translation and internationalization for software

Build and share AI-powered mini apps

Realtime database for modern applications

Open source in-app survey and experience research

AI Affiliate Network For Financial Companies

Automating airport baggage handling with robots

AI-driven exam prep

Create hit songs with AI

Sovereign operating system for intelligence

We turn complex API integrations into drop-in full-stack libraries

Search infrastructure with hybrid retrieval for AI apps

Open source business automation platform

Freight bill audits and AP/AR automation for brokers

Open source platform for product integrations

Medical Voice Agents for Patient Management

Containerised CI/CD builds that run anywhere

Find and resolve issues in data center engineering using AI

A Collaborative, AI-native IDE for Hardware Engineers

Developer-first backend framework with built-in infra

Training the next generation of protein foundation models

Test, monitor, and improve your voice agents

AI to monitor thousands of security cameras.

Open source developer platform for scripts and workflows

Building the open source smart glasses operating system.

Design and sell products in minutes

AI that continuously optimises your website copy

API integration platform and GraphQL federation

AI Employees for Hotels

Open source business intelligence with Markdown and SQL

Foundation models for time series

B2B buy-now-pay-later payments

API security testing and DAST for developers

Collaborative SQL notebooks for data teams

Intelligent Medical Record Reviews

Platform to build, use, and monetize fully autonomous agents

Helping hospitals identify and prevent avoidable harm using AI

Carbon removal and climate project infrastructure

AI-native ATS/CRM for recruiting firms

In-Space Refueling

Fusion reactors for ships

Robinhood for Pokemon cards

Custom Parts, Manufactured in America

Getting companies refunds on tariffs and duties

AI review layer that decides which code changes need attention

Automated revenue cycle management, starting with dentists

The world's first vibe working platform

Digital AI humans that model clothes for e-commerce

Building long running autonomous coding agents

AI avatars to scale healthcare training

From data to enterprise insights in just a few words

AI co-pilot for sales reps at industrial wholesale distributors

Automate any workflow using plain english

Hire amazing engineers by seeing how they use AI

The OS for hospital workforce management

AI agents built for insurance.

Your key to the hotel market.

Uses AI to increase grid-connected battery storage revenue 2x

ChatGPT-style UI for any LLM

The largest live shopping marketplace in North America

Building blocks for digital commerce

Call 100+ LLMs with one interface

The ultimate multi-model database

Drag-and-drop UI to build LLM flows

Simple, fast, privacy-focused web analytics

Open source GraphQL-first e-commerce platform

Open source authentication that is 10x easier

Open source AI-powered screen and audio recorder

The open source LLM evaluation framework

Open source session replay and debugging suite

Open source observability with 140x lower storage costs

Integration platform for AI agents

Open source observability and on-call platform

Open source observability platform

The interface layer for your database

The fastest spreadsheet in the browser

Open source AI agent platform

No-code AI phone call agents for any business

Automated sales tax compliance for modern commerce

Open source customer engagement platform

AI agents that autonomously browse the web

Collaborative SQL notebooks for data teams