Find the Right YC Founders. Reach Out Better.

Search 900+ YC startups, find the right founders, and send personalized cold DMs in minutes.

4038Companies
/
SortA-Z
OpenCurriculum logo

OpenCurriculum

YCombinator

Helping K-12 teachers and school administrators build awesome…

A library of community curated teaching and learning materials, free to the entire world. Come collaborate; we can teach better together. OpenCurriculum, Inc. is a California based technology nonprofit organization with a mission to bring openness and innovation to K12 education around the world

Sacramento, CAWinter 2014ActiveArtificial IntelligenceEducation
OpenHack logo

OpenHack

YCombinator

Always-on AI security engineer

OpenHack is an always on AI Security Engineer. OpenHack understands your business, system design and developer intent like a real security engineer. It ingests all this context to find the hardest vulnerabilities through AI codebase scanning, AI pentesting and Supply Chain Security. It verifies and prioritizes vulnerabilities automatically, and filters out false positives like a real security engineer drastically reducing overhead.

B2BSan FranciscoArtificial IntelligenceDevSecOpsCybersecurity
OpenInvest logo

OpenInvest

YCombinator

Values based personalization at scale for asset and wealth management

OpenInvest is the first technology-backed, socially responsible investment asset management platform that aligns your investments with your values. OpenInvest’s proprietary technology seamlessly creates low-cost investment portfolios tailored to your values, while tracking market indices. A mission-driven company, OpenInvest was one of the first VC-backed Public Benefit Corporations.

San FranciscoSummer 2015AcquiredFintechInvestingSan Francisco
Openlayer logo

Openlayer

YCombinator

The fastest way to ship airtight AI

Openlayer is the governance platform for AI applications.

B2BSan FranciscoAIOpsArtificial IntelligenceDeveloper ToolsGenerative AIMachine Learning
Opennote logo

Opennote

YCombinator

The notebook that thinks with you.

Opennote is a notebook with an AI thinking partner built in. Feynman lives in your work: it edits your writing, references your knowledge and the web, runs background tasks, and gives feedback as you work.

San FranciscoSummer 2025ActiveAI-Enhanced LearningEducationSaaSConsumerProductivitySan Francisco
Quo (fka OpenPhone) logo

Quo (fka OpenPhone)

YCombinator

The all-in-one business phone for teams.

OpenPhone is the modern business phone system. It comes with powerful calling, messaging, and a lightweight CRM. Works great for individuals and teams. It allows you to share a phone number with teammates, like an inbox. Available on Mac, Windows, Web, iOS, and Android.

B2BSan FranciscoSaaS
OpenPipe logo

OpenPipe

YCombinator

Turn expensive prompts into cheap fine-tuned models

OpenPipe is an SDK that abstracts away fine-tuning custom models. We capture your existing provider’s prompt-completion pairs in the background and use them to create a new model that is faster, cheaper and often more accurate than the original.

B2BSeattle, WAAIOpsArtificial IntelligenceOpen Source
OpenProse logo

OpenProse

YCombinator

An open-source operating system for reliable long-running agents

OpenProse is building open-source infrastructure for long-running AI work: a declarative language plus the Reactor harness/runtime for reliable agent workflows. Our organic open-source traction (7k+ installs) has already translated into a customer at a medical research lab, starting with a $10k pilot set to roll into a $10k/month contract. YC recruited us into the current batch and we've since hired two senior founding team members (ex-Google, Forbes 30u30 harness engineer). All three founding team members are two time founders. We've raised $1.25M in the last two weeks from Jonathan Abrams 8-Bit Capital, Otis Chandler, and other angels.

San FranciscoSpring 2026ActiveSan Francisco
OpenRelay logo

OpenRelay

YCombinator

Distributed, hardware-agnostic AI inference

OpenRelay is an innovative startup in the tech space.

Seattle, WASummer 2026ActiveAISeattle
Openroll logo

Openroll

YCombinator

The AI workforce for People and Finance teams

Openroll is an AI-powered workspace for people and finance teams. Openroll lets teams automate recurring work and run fully auditable workflows across their systems. Compensation, headcount, and budgeting in one platform. Learn more at https://www.openroll.com

Stockholm, SwedenFall 2025ActiveArtificial IntelligenceB2BProductivityHR TechEnterprise Software
PreviousPage 247 of 404Next